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Image-guided brachytherapy for cervical cancer: A Canadian Brachytherapy Group survey
Brachytherapy 10 (2011) 345e351
Image-guided brachytherapy for cervical cancer: A Canadian Brachytherapy Group survey Simon Pavamani1, David P. D’Souza2, Lorraine Portelance3, Peter S. Craighead1, Andrew G. Pearce4, Laurel L. Traptow5, Corinne M. Doll1,* 1 Department of Oncology, University of Calgary, Calgary, Alberta, Canada Department of Radiation Oncology, University of Western Ontario, London, Ontario, Canada 3 Department of Radiation Oncology, McGill University, Montreal, Quebec, Canada 4 Department of Radiation Oncology, Sudbury Regional Cancer Center, Sudbury, Ontario, Canada 5 Department of Medical Physics, Tom Baker Cancer Center, Calgary, Alberta, Canada 2
ABSTRACT
PURPOSE: To survey the current use and future plans for image-guided brachytherapy (BT) for cervical cancer by radiation oncologists in Canada. METHODS AND MATERIALS: Canadian radiation oncologists treating gynecologic malignancies were identified in January 2009. A 29-item questionnaire (English and French) querying the current practice in the use of imaging in BT planning, and plans for transition to three-dimensional (3D) image guidance for BT for cervical cancer (curative intent, intact cervix), was electronically circulated. Questionnaire responses were tabulated and analyzed by respondent and by center. RESULTS: Response rate was 62% (36 of 58 radiation oncologists), representing 71% (22 of 31) of Canadian radiation oncology centers with a gynecologic BT facility. Most of the centers were using high-dose-rate BT (68%), followed by low-dose-rate BT (23%) and pulsed dose-rate BT (10%). Main imaging used for treatment planning by center was plain X-ray (50%), computerized tomography (CT) (45%), and magnetic resonance imaging (MRI) (5%). For respondents using CT or MRI for planning, point Awas the most common dose prescription point (50%), followed by gross tumor volume/clinical target volume as per Groupe Europeen de Curietherapie and the European Society for Therapeutic Radiology and Oncology guidelines (44%). For centers using plain X-rays for planning, 73% planned to transition to a 3D image-based approach, with the majority to adopt CT imaging. Eighty percent of respondents agreed that 3D image-guided BT should become standard of care for treatment of cervical cancer in Canada, and additionally support the development of national guidelines. CONCLUSIONS: Most of the Canadian radiation oncologists surveyed and Canadian cancer centers are either using 3D imaging and planning or transitioning to a 3D image-based approach within the next year. Point A remained a commonly documented prescription point. Access to MRI was very low. These results may lead to national treatment guidelines. Ó 2011 Published by Elsevier Inc on behalf of American Brachytherapy Society.
Keywords:
Image-guided brachytherapy; Cervical cancer; Pattern of practice
Introduction Received 12 July 2010; received in revised form 8 December 2010; accepted 14 December 2010. Conflict of interest notification: None of the authors have any potential conflict of interest to disclose. Meeting presentation: Oral presentation at the Canadian Association of Radiation Oncology Annual Scientific Meeting, Canadian Brachytherapy Group, Quebec City, Quebec, Canada, September 30, 2009. * Corresponding author. Department of Oncology, University of Calgary, Tom Baker Cancer Centre, 1331 29th Street NW, Room CC113A, Calgary, Alberta T2N 4N2, Canada. Tel.: þ1-403-521-3708; fax: þ1403-283-1651. E-mail address: [email protected] (C.M. Doll).
Brachytherapy (BT) has been used in the treatment of patients with cervical cancer since the early 1900s. The Manchester system has been the most commonly used method to prescribe radiation dose in cervical cancer BT. In this method of planning, referred to as twodimensional (2D), plain X-rays (orthogonal films) are used to plan and prescribe dose to a set of defined points (1). These points represent the lateral extent of the cervix (point A), and the approximate location of the obturator nodes (point B). For optimal disease control, the recommended
1538-4721/$ - see front matter Ó 2011 Published by Elsevier Inc on behalf of American Brachytherapy Society. doi:10.1016/j.brachy.2010.12.004
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total low-dose-rate (LDR) equivalent dose to point A is 80e90 Gy, including external beam radiotherapy (EBRT) and BT (2, 3). The International Commission on Radiation Units and Measurements (ICRU), a standardization body of the International Congress of Radiology, has also recommended reporting of bladder and rectal point doses, in an effort to estimate the risk of complications to these normal tissues (4). This was done in an effort to standardize the reporting of doses to these normal tissues, which would allow for an objective estimation of toxicity associated with a range of doses. However, computerized tomography (CT)-assisted dosimetry studies looking specifically at bladder, rectal, and sigmoid doses reported that these doses are underestimated when determined using the ICRU system (5). This suggests that critical structures receive doses that are often higher than traditional 2D planning techniques document. These findings, and other developments in EBRT, have led to the development of threedimensional (3D) image-guided BT, in an effort to improve dosing to the tumor, and reduce the dose to the sensitive normal tissues. The move to 3D image-guided BT was initiated by the Gynecologic Groupe Europeen de Curietherapie and the European Society for Therapeutic Radiology and Oncology (GYN GEC-ESTRO) Working Group, who published their recommendations in 2005 and 2006 (6, 7). The Vienna group, who were a part of the GYN GEC-ESTRO Working Group, reported their experience on 145 patients with cervical cancer treated with 3D image-guided BT. They reported a 3-year local control rate of 85%, which was higher than the 67% control rate for patients treated with traditional 2D BT in their own center during an earlier period. The overall Grade 3/4 toxicity was 6% compared with 13% in patients treated without 3D image-based BT (8, 9). As a result of the consensus reached by the GYN GECESTRO Working Group, and data on the experience with 3D BT planning in patients with cervical cancer, many radiation oncology centers in North America have moved to or are transitioning to 3D image-guided BT for cervical cancer. In 2004, the Image-Guided Brachytherapy Working Group of the American Brachytherapy Society (ABS) published their guidelines for image-based BT for cervical cancer for North America (10). In 2005, at a joint consensus meeting, the ABS and the GEC-ESTRO decided to adopt the guidelines from the GEC-ESTRO as their common template for the implementation of 3D imagebased planning in the United States. A recent survey conducted by the ABS showed that more than half of its members in the United States are using CT imaging in BT for cervical cancer (11). In Canada, 3D image-based BT for cervical cancer was the subject of a workshop at the Canadian Association of Radiation Oncology Annual Meeting in 2007. This focused on the rationale for using imaging for 3D planning for cervical cancer BT and 3D planning techniques. Although a previous Canadian survey was performed in 2006 to
document the change in practice from LDR BT, there are no publications documenting the use of image-guided BT for cervical cancer in Canada (12). The purpose of this present survey was to determine the current use and future plans of image-guided BT for cervical cancer by Canadian radiation oncologists, and by cancer center.
Methods and materials In January 2009, all Canadian radiation oncologists treating gynecologic malignancies were identified using the Canadian Association of Radiation Oncology Web site, individual center directories, and phone queries to Canadian cancer center radiotherapy departments. A 29-item questionnaire in both official languages (English and French) querying the current practice in the use of imaging in BT planning, and plans for transition to 3D image guidance for BT for cervical cancer, was created electronically. These questions focused on the individual’s practice of cervical cancer BT, technology used at their center, and plans for the future. Questions were specifically focused on the treatment of cervical cancer patients (intact cervix) with radical radiation therapy (EBRT and BT) with curative intent, and did not pertain to patients treated in the postoperative setting. An e-mail message providing background information, the purpose of the survey, and a link to a web page for the survey was sent electronically to the identified radiation oncologists in February 2009 (13). A reminder e-mail was sent to nonrespondents in April 2009. Respondents could take part in the survey only once. Questionnaire responses were tabulated and analyzed by respondent and by center.
Results Respondent and center characteristics Of 58 radiation oncologists identified as treating gynecologic malignancies in Canada, 36 replied for a response rate of 62%. Frequency of cancer center survey responses by province is shown in Fig. 1. This represents responses from 71% (22 of 31) of Canadian radiation oncology centers with a gynecologic BT treatment facility. Eight of 10 Canadian provinces are represented in these responses. All respondents practice in an academic medical center or in a hospital-based practice with an academic affiliation. When asked how many patients the individual radiation oncologist treated in 2008, the most common response was between 10 and 20 patients (37%), followed by 20 and 30 patients (20%). Five of 36 respondents (14%) treated more than 30 patients in 2008. Four respondents did not treat any patients in 2008 because of a change of workplace or practice pattern; of those, two did not practice in 2009, and their results were thus deleted from the remainder of the survey analysis. Most of the respondents (68%, 23 of
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Fig. 2. Imaging modality used for brachytherapy planning by center. Fig. 1. Frequency of cancer center responses by province.
34) use high-dose-rate (HDR) BT, representing 68% (15 of 22) of Canadian cancer center-based responses. Twentyfour percent (8 of 34) use LDR BT, representing 23% (5 of 22) of cancer center-based responses. Twelve percent of respondents (4 of 34), representing two cancer centers, reported using pulsed dose-rate (PDR) BT, with one respondent (3%) using either PDR or HDR. Additionally, one respondent reported using both HDR and LDR at their center. Imaging modalities in use During BT applicator insertion Ultrasound (US) guidance for applicator insertion was used by 24% (8 of 34) of respondents on a routine basis, with 35% (12 of 34) reporting occasional use, and 38% (13 of 34) not using it. One respondent did not answer this question. Imaging post-insertion In-suite imaging was available in 36% (8 of 22) of the surveyed cancer centers, with the remaining centers requiring the movement of the patient out-of-suite for imaging (45%, 10 of 22). Some center’s respondents reported using both in-suite and out-of-suite imaging (18%; 4 of 22). There was a slightly higher use of plain X-ray (11 of 22 centers) vs. CT-based imaging (10 of 22 centers). Only one center used MRI. In one center, radiation oncologists used either plain X-rays or CT imaging-based planning. Further details of imaging used in Canadian centers for BT planning are shown in Fig. 2. Frequency of post-insertion imaging Of those respondents using CT or MRI, 83% (15 of 18) acquired imaging with each insertion, including those respondents using PDR and LDR BT in which there was only one insertion done. Eleven percent (2 of 18) of respondents using CT or MRI obtained images only for the first insertion. Twenty-two percent (4 of 18) of respondents
using CT or MRI for imaging used one insertion to deliver more than one BT treatment. Tumor and normal tissue contouring For respondents at the single cancer center using MRI for planning, 100% (3 of 3) contoured the gross tumor volume (GTV) at the time of the BT insertion (GTV BT), and the high-risk and the intermediate-risk clinical target volume (HR CTV and IR CTV). GTV at the time of diagnosis was additionally contoured by two-thirds of respondents. For respondents using CT for planning, 33% (5 of 15) contoured GTV BT, 20% (3 of 15) contoured HR CTV, and none contoured IR CTV. Forty-four percent (8 of 18) of respondents using CT imaging did not contour any of the above volumes for BT planning. Normal tissue or organ at risk (OAR) volume contouring for the rectum and urinary bladder was performed by 100% (18 of 18) of the respondents, whereas 72% (13 of 18), 44% (8 of 18), 33% (6 of 18), and 22% (4 of 18) contoured the sigmoid, small bowel, vagina, and the urethra, respectively. Dose prescription and reporting For respondents using CT or MRI, a 3D-based target volume plan was performed in 44% (8 of 18) of cases, using GEC-ESTRO or ABS guidelines, but not all of these plans were used to prescribe treatment. Among the respondents using MRI, 100% (3 of 3, one center) used the GECESTRO guidelines for dose prescription. Among those respondents using CT-based planning, 53% (8 of 15) were using point A alone for dose prescription, whereas 20% (3 of 15) used both point A and the GEC-ESTRO guidelines; and 2 of 15 used GEC-ESTRO (or ABS) guidelines alone; 2 respondents did not answer this question. In terms of target doseevolume histogram (DVH) parameters in the CT/MRI group, 39% (7 of 18) of respondents were defining D90 and D100 (the minimum dose delivered to 90% and 100% of the respective volume) for GTV BT, 28% (5 of 18) for HR CTV, and 11% (2 of 18) for IR CTV. Forty-four percent (8 of 18) were not defining D90 and D100 data for any targets. For OARs, most of the respondents were reporting rectal and bladder dose as the
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3D DVH D2 cc. The ICRU point dose for the rectum and bladder was used by 56% (10 of 18) and 50% (9 of 18), respectively. The remaining DVH parameters for rectum and bladder documented are illustrated in Fig. 3. All respondents reported the external beam and the BT doses separately, while additionally 11% (2 of 18) were also reporting the biologically weighted dose of the combination of external beam and BT. Six percent of the respondents additionally reported the physical dose and the dose rate of the combined treatment.
based planning, whereas only one center (12.5%) was planning to transition to a MRI-based system. The majority (91%) of Canadian radiation oncologists surveyed believe that 3D image-based BT planning should be the standard of care for cervical cancer treatment in Canada. Nine percent of the respondents were unsure; however, none were directly opposed to this move. The vast majority (80%) of respondents supported the development of Canadian guidelines for 3D image-based cervical cancer BT.
3D planning by region
Discussion
In terms of regional practice, Ontario had the highest utilization of 3D image-based planning of cancer centers represented in the survey, with 62% (5 of 8) of the centers using either CT or MRI. Half of the responding centers in the provinces of Alberta, Quebec and the Maritimes reported using 3D image-based treatment planning, as did 50% (2 of 4) of British Columbia cancer centers.
Although patterns of care surveys for BT practice have been performed in other countries, this survey is the first to assess the patterns of practice of 3D image-based BT for cervical cancer in Canada (11, 14e16). The goal of the study was to determine the current use and future plans for image-based BT for cervical cancer treatment in Canada, and to document treatment-planning practices by radiation oncologist and cancer center-based practice. There has been a significant shift in BT practice for cervical cancer in Canada, first documented in the 2006 Canadian survey, and now with further changes noted 3 years later (12). Several changes stand out, including the transition to HDR BT in most of the centers, the use of US during BT applicator insertion, the uptake of 3D-based imaging, and the move to 3D planning. When compared with the ABS survey, there are striking differences and similarities between the two countries. Relatively fewer Canadian- than American-based respondents are using US routinely to guide applicator placement (11). In the United States, the proportion of insertions guided by US was 56%, for those who have facilities for real-time image guidance, which was more than double that reported for routine use in the Canadian survey (24%). Additionally, 20% of the ABS survey respondents did not use US, compared with 38% of Canadian
Plans to transition to 3D image-based planning Seventy-three percent (8 of 11) of centers using plain Xrays at the time of the survey were preparing to transition to 3D-based BT planning, whereas 18% (2 of 11) were undecided about the transition. Nine percent of the respondents (representing one center) were not planning to adopt 3Dbased BT planning. For respondents who were undecided or not planning to transition to 3D-based BT planning, budgetary (50%) and technical reasons (50%), and lack of having timely access to CT or MRI, were reasons cited. For those centers planning to transition to 3D-based BT planning, the majority (75%, 6 of 8) were planning to do so within 1 year, with 25% (2 of 8) taking 1e3 years to make the change. Of those centers planning to change, the majority (88%, 7 of 8) were planning to adopt CT-
Fig. 3. Dose reporting used for bladder and rectum.
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respondents. The use of US-guided applicator placement has been shown to reduce the rate of uterine perforation and results in accurate placement of the applicators (17). Furthermore, for acquiring 3D volumes, CT was overall used less often in Canada than in the United States (45% vs. 55%). However, when 3D imaging was performed, CT was the most common modality used, with only 9% (3 of 34) of respondents (one Canadian gynecologic BT center) using MRI for BT planning at the time of this survey in 2009. The relatively low usage of MRI is similar to the practice documented in the United States, and is likely based on the relative rarity of MRI scanners accessible to radiotherapy departments in both countries for routine use. The use of plain films for BT treatment planning was similar to the surveyed ABS members (11). There was some regional variation in practice, with Ontario having the highest utilization of 3D image-based planning. Of Canadian provinces, Ontario has the highest population and two-thirds of the country’s cancer centers with a gynecologic radiation treatment facility. For respondents using CT or MR imaging for planning, OAR contouring was performed by all physicians for the rectum and bladder. Although the majority did contour target volumes, with the most common being GTV BT, there was still a significant proportion who did not. These volumes were contoured most commonly based on the guidelines of the GEC-ESTRO Working Group (6, 7). According to these guidelines, DVH parameters, that is, D90 and D100 are to be reported for GTV, HR CTV, and IR CTV to evaluate the complex dose heterogeneity. According to this document, V150 and V200 (the volume enclosed by 150% or 200% of the prescribed dose) are essential for overall assessment of high-dose volumes. Interestingly, although the most important target volume concept in the GEC-ESTRO guidelines is the HR CTV, there were a higher proportion of respondents contouring GTV BT. Although GEC-ESTRO guidelines define GTV BT based on T2weighted MRI, some respondents are attempting to contour this volume based on CT imaging. Viswanathan et al. (18) have shown that CT-based tumor contours can significantly overestimate the tumor width, resulting in significant differences in the DVH parameters compared with MRI, and that MRI remains the standard for CTV definition. Despite the contouring of these structures and volumes, most of the respondents were still using point A as the BT prescription point. This practice is very similar to those by ABS members surveyed, 76% of whom followed this dose prescription method. In our survey, 44% of respondents who used CT or MRI were using the 3D GTV/CTV (GEC-ESTRO) guidelines for their dose prescription. This figure was similar to the corresponding ABS member survey. For OAR dose reporting, there were a higher percentage of Canadian respondents reporting normal tissue D2 cc DVH parameters compared with the ABS survey. Overall, the results of the two surveys were remarkably similar.
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Although the GEC-ESTRO recommends MRI-contoured volumes for target delineation, the vast majority of Canadian centers do not have routine access to MRI for BT planning for cervical cancer patients. This is a challenge likely faced by most centers, worldwide, and is also reflected in the ABS survey. As this is a reality that won’t be easily modified, it is useful to evaluate CT vs. MRI planning for this patient group. Viswanathan et al. (18), recognizing this issue, performed a prospective study comparing CT and MRI, and contoured the tumor and OARs using the GEC-ESTRO guidelines. They found that the two modalities were similar with respect to the OAR contouring and DVH analysis, but MRI was superior in terms of contouring the various GECESTRO tumor definitions. The use of CT will at least allow better delineation of normal tissues than plain X-ray based planning, and this may translate into reduced toxicity for these patients. Other studies have shown that the DVH analysis of 2D plans reveal suboptimal coverage of CT-based cervix and a negative correlation between coverage and cervical size (19). However, Tan et al. (20) demonstrated that even using CT-based contouring and planning techniques, defining HR CTV by including the entire cervix and all visible and palpable tumor at examination under anesthesia, local control was improved compared with a cohort treated with conventional planning techniques. Additional validation of the results of MRIeguided BT in locally advanced cervical cancer is underway, as the EMBRACE (MRI-based BT for locally advanced cervix cancer), a prospective multicenter trial, continues to accrue patients (21). Among radiation oncologists continuing to use plain films for BT planning, the majority were planning to transition to 3D image-based planning within 1 year, and most likely would adopt CT-based planning. There was strong support for both 3D-based imaging as the standard of care for cervical cancer BT, and the development of national guidelines. As 3D imaging is now considered the standard of care for BT planning for cervical cancer, we recommend establishment of national treatment guidelines for this patient group. Several limitations to this study must be mentioned. The survey captures practice patterns from the time period from which the survey was administered, in an era where practice may be changing rapidly. As this survey and the ABS survey were not conducted over identical time periods, there are challenges in directly comparing the two survey results. However, formally documenting image-guided BT practice for cervical cancer by radiation oncologists and Canadian cancer centers is important, as Canada continues to be a significant contributor to international clinical trials.
Conclusions Most of the Canadian radiation oncologists surveyed and Canadian cancer centers are either using 3D imaging and planning or transitioning to a 3D image-based approach
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within the next year. Point A remained a commonly documented prescription point. Access to MRI was very low. These results may lead to national treatment guidelines.
Acknowledgments The authors would like to acknowledge Dr. Gerard Morton and Dr. Jim Morris from the Canadian Brachytherapy Group for their support, Marie-Eve Cote and Dr. Marc Kerba for their assistance in French translation, and all those who participated in this survey.
References [1] Tod MC, Meredith WJ. A dosage system for use in the treatment of cancer of the uterine cervix. Br J Radiol 1938;11:809e824. [2] Perez CA, Breaux S, Madoc-Jones H, et al. Radiation therapy alone in the treatment of carcinoma of uterine cervix. I. Analysis of tumor recurrence. Cancer 1983;51:1393e1402. [3] Perez CA, Camel HM, Kuske RR, et al. Radiation therapy alone in the treatment of carcinoma of the uterine cervix: A 20-year experience. Gynecol Oncol 1986;23:127e140. [4] International Commission of Radiation Units and Measurements. Dose and volume specification for reporting intracavitary therapy in gynaecology. ICRU report 38. Bethesda, MD: International Commission of Radiation Units and Measurements; 1985. [5] Kapp KS, Stuecklschweiger GF, Kapp DS, et al. Dosimetry of intracavitary placements for uterine and cervical carcinoma: Results of orthogonal film, TLD, and CT-assisted techniques. Radiother Oncol 1992;24:137e146. [6] Haie-Meder C, P€ otter R, Van Limbergen E, et al. Recommendations from Gynaecological (GYN) GEC-ESTRO Working Group (I): Concepts and terms in 3D image-based 3D treatment planning in cervix cancer brachytherapy with emphasis on MRI assessment of GTV and CTV. Radiother Oncol 2005;74:235e245. [7] P€ otter R, Haie-Meder C, Van Limbergen E, et al. Recommendations from Gynaecological (GYN) GEC-ESTRO Working Group (II): Concepts and terms in 3D image-based treatment planning in cervix cancer brachytherapy - 3D dose volume parameters and aspects of 3D image-based anatomy, radiation physics, and radiobiology. Radiother Oncol 2006;78:67e77. [8] P€ otter R, Knocke TH, Fellner C, et al. Definitive radiotherapy based on HDR brachytherapy with iridium 192 in uterine cervix carcinoma: Report on the Vienna University Hospital findings (1993e1997) compared to the preceding period in the context of ICRU 38 recommendations. Cancer Radiother 2000;4:159e172. [9] P€ otter R, Dimopoulos J, Georg P, et al. Clinical impact of MRI assisted dose volume adaptation and dose escalation in brachytherapy of locally advanced cervix cancer. Radiother Oncol 2007;83:148e155. [10] Nag S, Cardenes H, Chang S, et al. Proposed guidelines for imagebased intracavitary brachytherapy for cervical carcinoma: Report from Image-guided Brachytherapy Working Group. Int J Radiat Oncol Biol Phys 2004;60:1160e1172. [11] Viswanathan AN, Erickson BA. Three-dimensional imaging in gynecologic brachytherapy: A survey of the American Brachytherapy Society. Int J Radiat Oncol Biol Phys 2010;76:104e109. [12] Pearce A, Craighead P, Kay I, et al. Brachytherapy for carcinoma of the cervix: A Canadian survey of practice patterns in a changing era. Radiother Oncol 2009;91:194e196. [13] Available at: http://www.surveymonkey.com/. Accessed March 18, 2010.
[14] Guedea F, Ventura M, Mazeron J-J, et al. Patterns of care for brachytherapy in Europe: Facilities and resources in brachytherapy in the European area. Brachytherapy 2008;7:223e230. [15] Montana G, Hanlon A, Brickner T, et al. Carcinoma of the cervix: Patterns of care studies: Review of 1978, 1983 and 1988e1989 surveys. Int J Radiat Oncol Biol Phys 1995;32:1481e1486. [16] Toita T, Kodaira T, Shinoda A, et al. Patterns of radiotherapy practice for patients with cervical cancer (1999e2001): Patterns of care study in Japan. Int J Radiat Oncol Biol Phys 2008;70:788e794. [17] Davidson ATM, Yuen J, D’Souza DP, et al. Optimization of high-doserate cervix brachytherapy applicator placement: The benefits of intraoperative ultrasound guidance. Brachytherapy 2008;7:248e253. [18] Viswanathan AN, Dimopoulos J, Kirisits C, et al. Computed tomography versus magnetic resonance imaging-based contouring in cervical cancer brachytherapy: Results of a prospective trial and preliminary guidelines for standardized contours. Int J Radiat Oncol Biol Phys 2007;68:491e498. [19] Gao M, Albuquerque K, Chi A, et al. 3D CT-based volumetric dose assessment of 2D plans using GEC-ESTRO guidelines for cervical cancer brachytherapy. Brachytherapy 2010;9:55e60. [20] Tan L, Coles C, Hart C, et al. Clinical impact of computed tomography-based image guided brachytherapy for cervix cancer using the tandem-ring applicatordThe Addenbrooke’s experience. Clin Oncol 2009;21:175e182. [21] P€otter R, Fidarova E, Kirisits C, et al. Image-guided adaptive brachytherapy for cervix carcinoma. Clin Oncol (R Coll Radiol) 2008;20: 426e432.
Appendix Survey questionnaire 1. Approximately how many patients with cervical cancer did you treat with BT last year (2008)? 2. Which of the following BT methods do you currently use? (HDR, LDR, PDR) 3. Are you using US image guidance for intrauterine tube insertion? (Yes, no, sometimes) 4. Describe your center’s BT suite’s imaging (Imaging in-suite; patient moved outside suite for imaging) 5. What imaging are you currently using for BT planning for cervical cancer? (X-rays, cone beam CT, CT imaging, MRI) 6. Which 3D planning system do you use? 7. How often do you acquire a CT or MRI for BT treatment planning and dosimetry? (With the first insertion only; with every insertion; other [specify]) 8. If using a CT- or MRI-based planning approach, describe how you contour the following organs [(Bladder, rectum, sigmoid, vagina, small bowel, urethra, others [specify]; whole organ or adjacent wall)] 9. Which of the following volumes do you contour? (GTVD, GTV BT, HR CTV, IR CTV, none) 10. If using a CT- or MRI-based imaging and planning approach, on what do you base the dose prescription? (Point A, GEC-ESTRO guidelines, ABS guidelines) 11. How do you report the dose to point A? (Right/left; right, left & mean dose; other [specify])
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12. For which of the following contoured tumor volumes do you report the D100 and D90? (GTV, HR CTV, IR CTV, none) 13. Which reference point(s) do you record for reporting the dose to the following OARs? (Bladder, rectum: ICRU point, D0.1 cc, D1 cc, D2 cc, D5 cc [wall], D10 cc [wall]) 14. Which reference point(s) do you record for reporting the dose to the sigmoid? (D0.1 cc, D1 cc, D2 cc, D5 cc [wall], D10 cc [wall], none) 15. Are you reporting the dose to the vagina? (No, yes [specify]) 16. What do you record as a summary of the total dose values for the entire treatment (external beam and BT)? (External beam and BT doses, recorded separately; physical dose with fractionation and dose rate of combined treatment; biologically weighted dose of combined treatment; other [specify]) 17. Do you deliver more than one fraction of BT for each individual insertion? (Yes, no, sometimes) 18. If X-rays are being currently used for planning, are you planning to transition to a 3D image-based approach? (Yes, no, undecided) 19. If yes, what time frame are you looking at for the transition? (!1, 1e3, O3 years) 20. If so, what imaging modality do you plan to adopt? (CT based, MRI based, undecided)
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21. If there are no plans to transition to a 3D imagebased planning, list the reason/reasons: (Budgetary, technical, timely access to CT or MRI, insufficient evidence, comments) 22. In the use of EBRT in combination with BT for EARLY stage disease (IB, IIA), what is your usual total pelvic external beam dose and fractionation? 23. In the use of EBRT in combination with BT for ADVANCED stage disease (IIB, III, and IVA), what is your usual total pelvic external beam dose and fractionation? 24. What is your typical BT dose and fractionation for EARLY stage disease (IB, IIA)? 25. What is your typical BT dose and fractionation for ADVANCED stage disease (IIB, III, and IVA)? 26. Image-guided (3D) BT should become the standard of care in the treatment of cervical cancer in Canada. (Strongly agree, somewhat agree, somewhat disagree, strongly disagree, undecided) 27. Would you support the development of national guidelines image-guided BT for cervical cancer? (Yes, no, undecided) 28. How do you think this would be done? (Workshop, survey-based guideline development, web-based development, combination) 29. Do you consent to your anonymous responses being used for research purposes? (Yes, no)
Image-guided brachytherapy for cervical cancer: A Canadian Brachytherapy Group survey Simon Pavamani1, David P. D’Souza2, Lorraine Portelance3, Peter S. Craighead1, Andrew G. Pearce4, Laurel L. Traptow5, Corinne M. Doll1,* 1 Department of Oncology, University of Calgary, Calgary, Alberta, Canada Department of Radiation Oncology, University of Western Ontario, London, Ontario, Canada 3 Department of Radiation Oncology, McGill University, Montreal, Quebec, Canada 4 Department of Radiation Oncology, Sudbury Regional Cancer Center, Sudbury, Ontario, Canada 5 Department of Medical Physics, Tom Baker Cancer Center, Calgary, Alberta, Canada 2
ABSTRACT
PURPOSE: To survey the current use and future plans for image-guided brachytherapy (BT) for cervical cancer by radiation oncologists in Canada. METHODS AND MATERIALS: Canadian radiation oncologists treating gynecologic malignancies were identified in January 2009. A 29-item questionnaire (English and French) querying the current practice in the use of imaging in BT planning, and plans for transition to three-dimensional (3D) image guidance for BT for cervical cancer (curative intent, intact cervix), was electronically circulated. Questionnaire responses were tabulated and analyzed by respondent and by center. RESULTS: Response rate was 62% (36 of 58 radiation oncologists), representing 71% (22 of 31) of Canadian radiation oncology centers with a gynecologic BT facility. Most of the centers were using high-dose-rate BT (68%), followed by low-dose-rate BT (23%) and pulsed dose-rate BT (10%). Main imaging used for treatment planning by center was plain X-ray (50%), computerized tomography (CT) (45%), and magnetic resonance imaging (MRI) (5%). For respondents using CT or MRI for planning, point Awas the most common dose prescription point (50%), followed by gross tumor volume/clinical target volume as per Groupe Europeen de Curietherapie and the European Society for Therapeutic Radiology and Oncology guidelines (44%). For centers using plain X-rays for planning, 73% planned to transition to a 3D image-based approach, with the majority to adopt CT imaging. Eighty percent of respondents agreed that 3D image-guided BT should become standard of care for treatment of cervical cancer in Canada, and additionally support the development of national guidelines. CONCLUSIONS: Most of the Canadian radiation oncologists surveyed and Canadian cancer centers are either using 3D imaging and planning or transitioning to a 3D image-based approach within the next year. Point A remained a commonly documented prescription point. Access to MRI was very low. These results may lead to national treatment guidelines. Ó 2011 Published by Elsevier Inc on behalf of American Brachytherapy Society.
Keywords:
Image-guided brachytherapy; Cervical cancer; Pattern of practice
Introduction Received 12 July 2010; received in revised form 8 December 2010; accepted 14 December 2010. Conflict of interest notification: None of the authors have any potential conflict of interest to disclose. Meeting presentation: Oral presentation at the Canadian Association of Radiation Oncology Annual Scientific Meeting, Canadian Brachytherapy Group, Quebec City, Quebec, Canada, September 30, 2009. * Corresponding author. Department of Oncology, University of Calgary, Tom Baker Cancer Centre, 1331 29th Street NW, Room CC113A, Calgary, Alberta T2N 4N2, Canada. Tel.: þ1-403-521-3708; fax: þ1403-283-1651. E-mail address: [email protected] (C.M. Doll).
Brachytherapy (BT) has been used in the treatment of patients with cervical cancer since the early 1900s. The Manchester system has been the most commonly used method to prescribe radiation dose in cervical cancer BT. In this method of planning, referred to as twodimensional (2D), plain X-rays (orthogonal films) are used to plan and prescribe dose to a set of defined points (1). These points represent the lateral extent of the cervix (point A), and the approximate location of the obturator nodes (point B). For optimal disease control, the recommended
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total low-dose-rate (LDR) equivalent dose to point A is 80e90 Gy, including external beam radiotherapy (EBRT) and BT (2, 3). The International Commission on Radiation Units and Measurements (ICRU), a standardization body of the International Congress of Radiology, has also recommended reporting of bladder and rectal point doses, in an effort to estimate the risk of complications to these normal tissues (4). This was done in an effort to standardize the reporting of doses to these normal tissues, which would allow for an objective estimation of toxicity associated with a range of doses. However, computerized tomography (CT)-assisted dosimetry studies looking specifically at bladder, rectal, and sigmoid doses reported that these doses are underestimated when determined using the ICRU system (5). This suggests that critical structures receive doses that are often higher than traditional 2D planning techniques document. These findings, and other developments in EBRT, have led to the development of threedimensional (3D) image-guided BT, in an effort to improve dosing to the tumor, and reduce the dose to the sensitive normal tissues. The move to 3D image-guided BT was initiated by the Gynecologic Groupe Europeen de Curietherapie and the European Society for Therapeutic Radiology and Oncology (GYN GEC-ESTRO) Working Group, who published their recommendations in 2005 and 2006 (6, 7). The Vienna group, who were a part of the GYN GEC-ESTRO Working Group, reported their experience on 145 patients with cervical cancer treated with 3D image-guided BT. They reported a 3-year local control rate of 85%, which was higher than the 67% control rate for patients treated with traditional 2D BT in their own center during an earlier period. The overall Grade 3/4 toxicity was 6% compared with 13% in patients treated without 3D image-based BT (8, 9). As a result of the consensus reached by the GYN GECESTRO Working Group, and data on the experience with 3D BT planning in patients with cervical cancer, many radiation oncology centers in North America have moved to or are transitioning to 3D image-guided BT for cervical cancer. In 2004, the Image-Guided Brachytherapy Working Group of the American Brachytherapy Society (ABS) published their guidelines for image-based BT for cervical cancer for North America (10). In 2005, at a joint consensus meeting, the ABS and the GEC-ESTRO decided to adopt the guidelines from the GEC-ESTRO as their common template for the implementation of 3D imagebased planning in the United States. A recent survey conducted by the ABS showed that more than half of its members in the United States are using CT imaging in BT for cervical cancer (11). In Canada, 3D image-based BT for cervical cancer was the subject of a workshop at the Canadian Association of Radiation Oncology Annual Meeting in 2007. This focused on the rationale for using imaging for 3D planning for cervical cancer BT and 3D planning techniques. Although a previous Canadian survey was performed in 2006 to
document the change in practice from LDR BT, there are no publications documenting the use of image-guided BT for cervical cancer in Canada (12). The purpose of this present survey was to determine the current use and future plans of image-guided BT for cervical cancer by Canadian radiation oncologists, and by cancer center.
Methods and materials In January 2009, all Canadian radiation oncologists treating gynecologic malignancies were identified using the Canadian Association of Radiation Oncology Web site, individual center directories, and phone queries to Canadian cancer center radiotherapy departments. A 29-item questionnaire in both official languages (English and French) querying the current practice in the use of imaging in BT planning, and plans for transition to 3D image guidance for BT for cervical cancer, was created electronically. These questions focused on the individual’s practice of cervical cancer BT, technology used at their center, and plans for the future. Questions were specifically focused on the treatment of cervical cancer patients (intact cervix) with radical radiation therapy (EBRT and BT) with curative intent, and did not pertain to patients treated in the postoperative setting. An e-mail message providing background information, the purpose of the survey, and a link to a web page for the survey was sent electronically to the identified radiation oncologists in February 2009 (13). A reminder e-mail was sent to nonrespondents in April 2009. Respondents could take part in the survey only once. Questionnaire responses were tabulated and analyzed by respondent and by center.
Results Respondent and center characteristics Of 58 radiation oncologists identified as treating gynecologic malignancies in Canada, 36 replied for a response rate of 62%. Frequency of cancer center survey responses by province is shown in Fig. 1. This represents responses from 71% (22 of 31) of Canadian radiation oncology centers with a gynecologic BT treatment facility. Eight of 10 Canadian provinces are represented in these responses. All respondents practice in an academic medical center or in a hospital-based practice with an academic affiliation. When asked how many patients the individual radiation oncologist treated in 2008, the most common response was between 10 and 20 patients (37%), followed by 20 and 30 patients (20%). Five of 36 respondents (14%) treated more than 30 patients in 2008. Four respondents did not treat any patients in 2008 because of a change of workplace or practice pattern; of those, two did not practice in 2009, and their results were thus deleted from the remainder of the survey analysis. Most of the respondents (68%, 23 of
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Fig. 2. Imaging modality used for brachytherapy planning by center. Fig. 1. Frequency of cancer center responses by province.
34) use high-dose-rate (HDR) BT, representing 68% (15 of 22) of Canadian cancer center-based responses. Twentyfour percent (8 of 34) use LDR BT, representing 23% (5 of 22) of cancer center-based responses. Twelve percent of respondents (4 of 34), representing two cancer centers, reported using pulsed dose-rate (PDR) BT, with one respondent (3%) using either PDR or HDR. Additionally, one respondent reported using both HDR and LDR at their center. Imaging modalities in use During BT applicator insertion Ultrasound (US) guidance for applicator insertion was used by 24% (8 of 34) of respondents on a routine basis, with 35% (12 of 34) reporting occasional use, and 38% (13 of 34) not using it. One respondent did not answer this question. Imaging post-insertion In-suite imaging was available in 36% (8 of 22) of the surveyed cancer centers, with the remaining centers requiring the movement of the patient out-of-suite for imaging (45%, 10 of 22). Some center’s respondents reported using both in-suite and out-of-suite imaging (18%; 4 of 22). There was a slightly higher use of plain X-ray (11 of 22 centers) vs. CT-based imaging (10 of 22 centers). Only one center used MRI. In one center, radiation oncologists used either plain X-rays or CT imaging-based planning. Further details of imaging used in Canadian centers for BT planning are shown in Fig. 2. Frequency of post-insertion imaging Of those respondents using CT or MRI, 83% (15 of 18) acquired imaging with each insertion, including those respondents using PDR and LDR BT in which there was only one insertion done. Eleven percent (2 of 18) of respondents using CT or MRI obtained images only for the first insertion. Twenty-two percent (4 of 18) of respondents
using CT or MRI for imaging used one insertion to deliver more than one BT treatment. Tumor and normal tissue contouring For respondents at the single cancer center using MRI for planning, 100% (3 of 3) contoured the gross tumor volume (GTV) at the time of the BT insertion (GTV BT), and the high-risk and the intermediate-risk clinical target volume (HR CTV and IR CTV). GTV at the time of diagnosis was additionally contoured by two-thirds of respondents. For respondents using CT for planning, 33% (5 of 15) contoured GTV BT, 20% (3 of 15) contoured HR CTV, and none contoured IR CTV. Forty-four percent (8 of 18) of respondents using CT imaging did not contour any of the above volumes for BT planning. Normal tissue or organ at risk (OAR) volume contouring for the rectum and urinary bladder was performed by 100% (18 of 18) of the respondents, whereas 72% (13 of 18), 44% (8 of 18), 33% (6 of 18), and 22% (4 of 18) contoured the sigmoid, small bowel, vagina, and the urethra, respectively. Dose prescription and reporting For respondents using CT or MRI, a 3D-based target volume plan was performed in 44% (8 of 18) of cases, using GEC-ESTRO or ABS guidelines, but not all of these plans were used to prescribe treatment. Among the respondents using MRI, 100% (3 of 3, one center) used the GECESTRO guidelines for dose prescription. Among those respondents using CT-based planning, 53% (8 of 15) were using point A alone for dose prescription, whereas 20% (3 of 15) used both point A and the GEC-ESTRO guidelines; and 2 of 15 used GEC-ESTRO (or ABS) guidelines alone; 2 respondents did not answer this question. In terms of target doseevolume histogram (DVH) parameters in the CT/MRI group, 39% (7 of 18) of respondents were defining D90 and D100 (the minimum dose delivered to 90% and 100% of the respective volume) for GTV BT, 28% (5 of 18) for HR CTV, and 11% (2 of 18) for IR CTV. Forty-four percent (8 of 18) were not defining D90 and D100 data for any targets. For OARs, most of the respondents were reporting rectal and bladder dose as the
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3D DVH D2 cc. The ICRU point dose for the rectum and bladder was used by 56% (10 of 18) and 50% (9 of 18), respectively. The remaining DVH parameters for rectum and bladder documented are illustrated in Fig. 3. All respondents reported the external beam and the BT doses separately, while additionally 11% (2 of 18) were also reporting the biologically weighted dose of the combination of external beam and BT. Six percent of the respondents additionally reported the physical dose and the dose rate of the combined treatment.
based planning, whereas only one center (12.5%) was planning to transition to a MRI-based system. The majority (91%) of Canadian radiation oncologists surveyed believe that 3D image-based BT planning should be the standard of care for cervical cancer treatment in Canada. Nine percent of the respondents were unsure; however, none were directly opposed to this move. The vast majority (80%) of respondents supported the development of Canadian guidelines for 3D image-based cervical cancer BT.
3D planning by region
Discussion
In terms of regional practice, Ontario had the highest utilization of 3D image-based planning of cancer centers represented in the survey, with 62% (5 of 8) of the centers using either CT or MRI. Half of the responding centers in the provinces of Alberta, Quebec and the Maritimes reported using 3D image-based treatment planning, as did 50% (2 of 4) of British Columbia cancer centers.
Although patterns of care surveys for BT practice have been performed in other countries, this survey is the first to assess the patterns of practice of 3D image-based BT for cervical cancer in Canada (11, 14e16). The goal of the study was to determine the current use and future plans for image-based BT for cervical cancer treatment in Canada, and to document treatment-planning practices by radiation oncologist and cancer center-based practice. There has been a significant shift in BT practice for cervical cancer in Canada, first documented in the 2006 Canadian survey, and now with further changes noted 3 years later (12). Several changes stand out, including the transition to HDR BT in most of the centers, the use of US during BT applicator insertion, the uptake of 3D-based imaging, and the move to 3D planning. When compared with the ABS survey, there are striking differences and similarities between the two countries. Relatively fewer Canadian- than American-based respondents are using US routinely to guide applicator placement (11). In the United States, the proportion of insertions guided by US was 56%, for those who have facilities for real-time image guidance, which was more than double that reported for routine use in the Canadian survey (24%). Additionally, 20% of the ABS survey respondents did not use US, compared with 38% of Canadian
Plans to transition to 3D image-based planning Seventy-three percent (8 of 11) of centers using plain Xrays at the time of the survey were preparing to transition to 3D-based BT planning, whereas 18% (2 of 11) were undecided about the transition. Nine percent of the respondents (representing one center) were not planning to adopt 3Dbased BT planning. For respondents who were undecided or not planning to transition to 3D-based BT planning, budgetary (50%) and technical reasons (50%), and lack of having timely access to CT or MRI, were reasons cited. For those centers planning to transition to 3D-based BT planning, the majority (75%, 6 of 8) were planning to do so within 1 year, with 25% (2 of 8) taking 1e3 years to make the change. Of those centers planning to change, the majority (88%, 7 of 8) were planning to adopt CT-
Fig. 3. Dose reporting used for bladder and rectum.
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respondents. The use of US-guided applicator placement has been shown to reduce the rate of uterine perforation and results in accurate placement of the applicators (17). Furthermore, for acquiring 3D volumes, CT was overall used less often in Canada than in the United States (45% vs. 55%). However, when 3D imaging was performed, CT was the most common modality used, with only 9% (3 of 34) of respondents (one Canadian gynecologic BT center) using MRI for BT planning at the time of this survey in 2009. The relatively low usage of MRI is similar to the practice documented in the United States, and is likely based on the relative rarity of MRI scanners accessible to radiotherapy departments in both countries for routine use. The use of plain films for BT treatment planning was similar to the surveyed ABS members (11). There was some regional variation in practice, with Ontario having the highest utilization of 3D image-based planning. Of Canadian provinces, Ontario has the highest population and two-thirds of the country’s cancer centers with a gynecologic radiation treatment facility. For respondents using CT or MR imaging for planning, OAR contouring was performed by all physicians for the rectum and bladder. Although the majority did contour target volumes, with the most common being GTV BT, there was still a significant proportion who did not. These volumes were contoured most commonly based on the guidelines of the GEC-ESTRO Working Group (6, 7). According to these guidelines, DVH parameters, that is, D90 and D100 are to be reported for GTV, HR CTV, and IR CTV to evaluate the complex dose heterogeneity. According to this document, V150 and V200 (the volume enclosed by 150% or 200% of the prescribed dose) are essential for overall assessment of high-dose volumes. Interestingly, although the most important target volume concept in the GEC-ESTRO guidelines is the HR CTV, there were a higher proportion of respondents contouring GTV BT. Although GEC-ESTRO guidelines define GTV BT based on T2weighted MRI, some respondents are attempting to contour this volume based on CT imaging. Viswanathan et al. (18) have shown that CT-based tumor contours can significantly overestimate the tumor width, resulting in significant differences in the DVH parameters compared with MRI, and that MRI remains the standard for CTV definition. Despite the contouring of these structures and volumes, most of the respondents were still using point A as the BT prescription point. This practice is very similar to those by ABS members surveyed, 76% of whom followed this dose prescription method. In our survey, 44% of respondents who used CT or MRI were using the 3D GTV/CTV (GEC-ESTRO) guidelines for their dose prescription. This figure was similar to the corresponding ABS member survey. For OAR dose reporting, there were a higher percentage of Canadian respondents reporting normal tissue D2 cc DVH parameters compared with the ABS survey. Overall, the results of the two surveys were remarkably similar.
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Although the GEC-ESTRO recommends MRI-contoured volumes for target delineation, the vast majority of Canadian centers do not have routine access to MRI for BT planning for cervical cancer patients. This is a challenge likely faced by most centers, worldwide, and is also reflected in the ABS survey. As this is a reality that won’t be easily modified, it is useful to evaluate CT vs. MRI planning for this patient group. Viswanathan et al. (18), recognizing this issue, performed a prospective study comparing CT and MRI, and contoured the tumor and OARs using the GEC-ESTRO guidelines. They found that the two modalities were similar with respect to the OAR contouring and DVH analysis, but MRI was superior in terms of contouring the various GECESTRO tumor definitions. The use of CT will at least allow better delineation of normal tissues than plain X-ray based planning, and this may translate into reduced toxicity for these patients. Other studies have shown that the DVH analysis of 2D plans reveal suboptimal coverage of CT-based cervix and a negative correlation between coverage and cervical size (19). However, Tan et al. (20) demonstrated that even using CT-based contouring and planning techniques, defining HR CTV by including the entire cervix and all visible and palpable tumor at examination under anesthesia, local control was improved compared with a cohort treated with conventional planning techniques. Additional validation of the results of MRIeguided BT in locally advanced cervical cancer is underway, as the EMBRACE (MRI-based BT for locally advanced cervix cancer), a prospective multicenter trial, continues to accrue patients (21). Among radiation oncologists continuing to use plain films for BT planning, the majority were planning to transition to 3D image-based planning within 1 year, and most likely would adopt CT-based planning. There was strong support for both 3D-based imaging as the standard of care for cervical cancer BT, and the development of national guidelines. As 3D imaging is now considered the standard of care for BT planning for cervical cancer, we recommend establishment of national treatment guidelines for this patient group. Several limitations to this study must be mentioned. The survey captures practice patterns from the time period from which the survey was administered, in an era where practice may be changing rapidly. As this survey and the ABS survey were not conducted over identical time periods, there are challenges in directly comparing the two survey results. However, formally documenting image-guided BT practice for cervical cancer by radiation oncologists and Canadian cancer centers is important, as Canada continues to be a significant contributor to international clinical trials.
Conclusions Most of the Canadian radiation oncologists surveyed and Canadian cancer centers are either using 3D imaging and planning or transitioning to a 3D image-based approach
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within the next year. Point A remained a commonly documented prescription point. Access to MRI was very low. These results may lead to national treatment guidelines.
Acknowledgments The authors would like to acknowledge Dr. Gerard Morton and Dr. Jim Morris from the Canadian Brachytherapy Group for their support, Marie-Eve Cote and Dr. Marc Kerba for their assistance in French translation, and all those who participated in this survey.
References [1] Tod MC, Meredith WJ. A dosage system for use in the treatment of cancer of the uterine cervix. Br J Radiol 1938;11:809e824. [2] Perez CA, Breaux S, Madoc-Jones H, et al. Radiation therapy alone in the treatment of carcinoma of uterine cervix. I. Analysis of tumor recurrence. Cancer 1983;51:1393e1402. [3] Perez CA, Camel HM, Kuske RR, et al. Radiation therapy alone in the treatment of carcinoma of the uterine cervix: A 20-year experience. Gynecol Oncol 1986;23:127e140. [4] International Commission of Radiation Units and Measurements. Dose and volume specification for reporting intracavitary therapy in gynaecology. ICRU report 38. Bethesda, MD: International Commission of Radiation Units and Measurements; 1985. [5] Kapp KS, Stuecklschweiger GF, Kapp DS, et al. Dosimetry of intracavitary placements for uterine and cervical carcinoma: Results of orthogonal film, TLD, and CT-assisted techniques. Radiother Oncol 1992;24:137e146. [6] Haie-Meder C, P€ otter R, Van Limbergen E, et al. Recommendations from Gynaecological (GYN) GEC-ESTRO Working Group (I): Concepts and terms in 3D image-based 3D treatment planning in cervix cancer brachytherapy with emphasis on MRI assessment of GTV and CTV. Radiother Oncol 2005;74:235e245. [7] P€ otter R, Haie-Meder C, Van Limbergen E, et al. Recommendations from Gynaecological (GYN) GEC-ESTRO Working Group (II): Concepts and terms in 3D image-based treatment planning in cervix cancer brachytherapy - 3D dose volume parameters and aspects of 3D image-based anatomy, radiation physics, and radiobiology. Radiother Oncol 2006;78:67e77. [8] P€ otter R, Knocke TH, Fellner C, et al. Definitive radiotherapy based on HDR brachytherapy with iridium 192 in uterine cervix carcinoma: Report on the Vienna University Hospital findings (1993e1997) compared to the preceding period in the context of ICRU 38 recommendations. Cancer Radiother 2000;4:159e172. [9] P€ otter R, Dimopoulos J, Georg P, et al. Clinical impact of MRI assisted dose volume adaptation and dose escalation in brachytherapy of locally advanced cervix cancer. Radiother Oncol 2007;83:148e155. [10] Nag S, Cardenes H, Chang S, et al. Proposed guidelines for imagebased intracavitary brachytherapy for cervical carcinoma: Report from Image-guided Brachytherapy Working Group. Int J Radiat Oncol Biol Phys 2004;60:1160e1172. [11] Viswanathan AN, Erickson BA. Three-dimensional imaging in gynecologic brachytherapy: A survey of the American Brachytherapy Society. Int J Radiat Oncol Biol Phys 2010;76:104e109. [12] Pearce A, Craighead P, Kay I, et al. Brachytherapy for carcinoma of the cervix: A Canadian survey of practice patterns in a changing era. Radiother Oncol 2009;91:194e196. [13] Available at: http://www.surveymonkey.com/. Accessed March 18, 2010.
[14] Guedea F, Ventura M, Mazeron J-J, et al. Patterns of care for brachytherapy in Europe: Facilities and resources in brachytherapy in the European area. Brachytherapy 2008;7:223e230. [15] Montana G, Hanlon A, Brickner T, et al. Carcinoma of the cervix: Patterns of care studies: Review of 1978, 1983 and 1988e1989 surveys. Int J Radiat Oncol Biol Phys 1995;32:1481e1486. [16] Toita T, Kodaira T, Shinoda A, et al. Patterns of radiotherapy practice for patients with cervical cancer (1999e2001): Patterns of care study in Japan. Int J Radiat Oncol Biol Phys 2008;70:788e794. [17] Davidson ATM, Yuen J, D’Souza DP, et al. Optimization of high-doserate cervix brachytherapy applicator placement: The benefits of intraoperative ultrasound guidance. Brachytherapy 2008;7:248e253. [18] Viswanathan AN, Dimopoulos J, Kirisits C, et al. Computed tomography versus magnetic resonance imaging-based contouring in cervical cancer brachytherapy: Results of a prospective trial and preliminary guidelines for standardized contours. Int J Radiat Oncol Biol Phys 2007;68:491e498. [19] Gao M, Albuquerque K, Chi A, et al. 3D CT-based volumetric dose assessment of 2D plans using GEC-ESTRO guidelines for cervical cancer brachytherapy. Brachytherapy 2010;9:55e60. [20] Tan L, Coles C, Hart C, et al. Clinical impact of computed tomography-based image guided brachytherapy for cervix cancer using the tandem-ring applicatordThe Addenbrooke’s experience. Clin Oncol 2009;21:175e182. [21] P€otter R, Fidarova E, Kirisits C, et al. Image-guided adaptive brachytherapy for cervix carcinoma. Clin Oncol (R Coll Radiol) 2008;20: 426e432.
Appendix Survey questionnaire 1. Approximately how many patients with cervical cancer did you treat with BT last year (2008)? 2. Which of the following BT methods do you currently use? (HDR, LDR, PDR) 3. Are you using US image guidance for intrauterine tube insertion? (Yes, no, sometimes) 4. Describe your center’s BT suite’s imaging (Imaging in-suite; patient moved outside suite for imaging) 5. What imaging are you currently using for BT planning for cervical cancer? (X-rays, cone beam CT, CT imaging, MRI) 6. Which 3D planning system do you use? 7. How often do you acquire a CT or MRI for BT treatment planning and dosimetry? (With the first insertion only; with every insertion; other [specify]) 8. If using a CT- or MRI-based planning approach, describe how you contour the following organs [(Bladder, rectum, sigmoid, vagina, small bowel, urethra, others [specify]; whole organ or adjacent wall)] 9. Which of the following volumes do you contour? (GTVD, GTV BT, HR CTV, IR CTV, none) 10. If using a CT- or MRI-based imaging and planning approach, on what do you base the dose prescription? (Point A, GEC-ESTRO guidelines, ABS guidelines) 11. How do you report the dose to point A? (Right/left; right, left & mean dose; other [specify])
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12. For which of the following contoured tumor volumes do you report the D100 and D90? (GTV, HR CTV, IR CTV, none) 13. Which reference point(s) do you record for reporting the dose to the following OARs? (Bladder, rectum: ICRU point, D0.1 cc, D1 cc, D2 cc, D5 cc [wall], D10 cc [wall]) 14. Which reference point(s) do you record for reporting the dose to the sigmoid? (D0.1 cc, D1 cc, D2 cc, D5 cc [wall], D10 cc [wall], none) 15. Are you reporting the dose to the vagina? (No, yes [specify]) 16. What do you record as a summary of the total dose values for the entire treatment (external beam and BT)? (External beam and BT doses, recorded separately; physical dose with fractionation and dose rate of combined treatment; biologically weighted dose of combined treatment; other [specify]) 17. Do you deliver more than one fraction of BT for each individual insertion? (Yes, no, sometimes) 18. If X-rays are being currently used for planning, are you planning to transition to a 3D image-based approach? (Yes, no, undecided) 19. If yes, what time frame are you looking at for the transition? (!1, 1e3, O3 years) 20. If so, what imaging modality do you plan to adopt? (CT based, MRI based, undecided)
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21. If there are no plans to transition to a 3D imagebased planning, list the reason/reasons: (Budgetary, technical, timely access to CT or MRI, insufficient evidence, comments) 22. In the use of EBRT in combination with BT for EARLY stage disease (IB, IIA), what is your usual total pelvic external beam dose and fractionation? 23. In the use of EBRT in combination with BT for ADVANCED stage disease (IIB, III, and IVA), what is your usual total pelvic external beam dose and fractionation? 24. What is your typical BT dose and fractionation for EARLY stage disease (IB, IIA)? 25. What is your typical BT dose and fractionation for ADVANCED stage disease (IIB, III, and IVA)? 26. Image-guided (3D) BT should become the standard of care in the treatment of cervical cancer in Canada. (Strongly agree, somewhat agree, somewhat disagree, strongly disagree, undecided) 27. Would you support the development of national guidelines image-guided BT for cervical cancer? (Yes, no, undecided) 28. How do you think this would be done? (Workshop, survey-based guideline development, web-based development, combination) 29. Do you consent to your anonymous responses being used for research purposes? (Yes, no)