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Early Outcomes and Dose-Volume Analysis for Patients With Cervical Cancer Treated With Computed Tomography-Based Treatment Planning in Brachytherapy
E314
International Journal of Radiation Oncology Biology Physics
Purpose/Objective(s): Pelvic sidewall dose from tandem and ring (TR) brachytherapy for cervical cancer is often used to approximate dose to the obturator and external iliac nodes, and determine the additional dose of EBRT needed for adequate control of any grossly involved nodes. However, previous published data have recommended caution when approximating sidewall dose in the era of image-guided brachytherapy utilizing volumetric planning. We performed a dosimetric analysis to specifically quantify sidewall dose in MRI-based TR brachytherapy. Materials/Methods: We evaluated 11 patients with cervical cancer treated with TR brachytherapy after completing a course of pelvic EBRT (45 Gy in 25 fractions). Foley catheter, vaginal packing, and a rectal retractor were used for all cases. Patients had stage I-III disease (5 stage I, 5 stage II, 1 stage III) without evidence of gross lymphadenopathy. All patients underwent CT simulation and MRI after applicator placement for treatment planning. High risk CTVs (HR-CTV) were delineated using T2-weighted MR sequences and organs at risk (OARs) using CT. Plans were generated for both insertions by manual optimization of dwell times. No sidewall dosimetry was incorporated in the optimization process. Twenty-eight Gy in 4 fractions was prescribed to D90 of the high risk CTV. Planning objectives (with dose contribution from EBRT) included: D90 HR-CTV Rx dose, D2cc rectum/sigmoid < 75 EQD2Gy, and D2cc bladder < 90 EQD2Gy. Sidewall calculations were performed on the axial mid-plane slice of the HR-CTV. Results: The median distance from the edge of the HR-CTV to the sidewall was 43.9 mm (range 35.8 e 50). The median distance from HR-CTV to the 50% IDL (approximately 60 Gy, by convention the dose to areas of initial parametrial involvement) was 24.5 mm (19.8 e 41.8). The median dose to the sidewall as a percentage of the Rx dose was 17.9% (8.2 - 21.6). For our dose fractionation, the absolute dose per fraction to the sidewall was 1.26 Gy (0.57 e 1.51). Conclusion: Dose to the pelvic sidewall using MR-based TR brachytherapy is variable and ranges from 8.2% to 21.58% of Rx dose (absolute dose 0.57 to 1.51 Gy per fraction) in this cohort. Patients with grossly involved pelvic nodes require individualized dosimetric evaluation when combining EBRT with image guided brachytherapy to avoid under-dosing nodal targets. Author Disclosure: M.Z. Kharouta: None. N. Sen: None. Y. Liao: None. D. Bernard: None. K.D. Kiel: None. J. Zhou: None.
rate, distant metastases rate, disease-specific survival rate, and treatmentrelated complications were compared between the two groups. Results: The median follow-up time was 38 months and the following rate was 96.1%. The surgery-based group resulted in comparable 3-years local recurrence rate (10.0% versus 12.1%, p Z 0. 47) to RT-based group. We found the 3-years disease-specific survival rate was higher for the RTbased group when compared with the surgery-based group (81.8% versus 60.0%, p Z 0.01). Moreover, the RT-based group also showed favorable results on the distant metastases rate (7.5% versus 40.0%, p Z 0.004) and the frequency of RTOG grade 3-4 late intestinal or urinary toxicities (6.1% versus 20.0%, p Z 0.006) comparing with the surgery-based group. Conclusion: Previous retrospective investigations showing the definitive chemo-radiation therapy was a superior approach than radical hysterectomy followed by postoperative radiation therapy with less treatmentrelated complications and favorable survival outcomes in patients with FIGO stage IIB cervical cancer. Author Disclosure: G. Cheng: None. M. He: None. H. Zhao: None. N. Zhang: None. Z. Yang: None. W. Yang: None.
2770 Radical Hysterectomy With Adjuvant Radiation Therapy Versus Definitive Radiation Therapy for International Federation of Gynecology and Obstetrics Stage IIb Cervical Cancer G. Cheng, M. He, H. Zhao, N. Zhang, Z. Yang, and W. Yang; Department of Radiation Oncology, China-Japan Union Hospital of Jilin University, Changchun, China Purpose/Objective(s): Cisplatin-based definitive chemo-radiation therapy was the primary treatment for FIGO stage IIB cervical cancer under the NCCN recommendation. However, in China, some patients with IIB stage after neoadjuvant chemotherapy have been subjected to radical hysterectomy. The aim of this study was to compare the treatment outcomes and adverse effects of radical hysterectomy followed by adjuvant radiation therapy with definitive chemo-radiation therapy in patients with FIGO stage IIB cervical cancer. Materials/Methods: We retrospectively reviewed the medical records of FIGO stage IIB cervical squamous cancer patients who were treated between October 2009 and January 2013. During the study period, 50 patients were treated with 2-3 cycles neoadjuvant chemotherapy, followed by radical hysterectomy and pelvic lymphadenectomy, all of the patients received the adjuvant external beam radiation therapy (EBRT) for 45-50.4 Gy in 25-28 fractions and three-dimensional high-dose-rate adaptive brachytherapy (3DHDR-ABT) for 10-20 Gy in 2-4 fractions weekly with or without adjuvant chemotherapy (surgery-based group). In addition, 66 patients received definitive chemo-radiation therapy consisted of pelvic EBRT for 45-50.4 Gy in 25-28 fractions plus concurrent platinum-based chemotherapy followed by 3D-HDR-ABT for 28 Gy in 4 fractions weekly (RT-based group). The patients were followed-up regularly in our institute. The local recurrence
2771 Surgery Versus Radiation Treatment for High-Grade Neuroendocrine Cancer of Uterine Cervix W.H. Hou,1 T.E. Schultheiss,2 J.Y.C. Wong,1 M.T. Wakabayashi,3 and Y.J. Chen1; 1Department of Radiation Oncology, City of Hope National Medical Center, Duarte, CA, 2Division of Physics, Department of Radiation Oncology, City of Hope National Medical Center, Duarte, CA, 3 Division of Gynecologic Oncology, Department of Surgery, City of Hope National Medical Center, Duarte, CA Purpose/Objective(s): To assess treatment and other factors impacting survival in high-grade neuroendocrine cervical carcinoma. Materials/Methods: We identified patients with high-grade neuroendocrine cervical cancers that were diagnosed during 1988-2012 in the Surveillance Epidemiology and End Results (SEER) database. We employed Kaplan-Meier analysis with log-rank test to determine and compare the overall survival by FIGO stages and by local treatment modalities (radical surgery and external beam radiation therapy (EBRT) with or without brachytherapy). We used proportional hazard analysis to determine the influence of age, stage and treatment modality on survival. Results: We identified a total of 832 cases of high-grade neuroendocrine cervical cancers. Mean age was 49.5 years old (range 19 to 95). After excluding the cases with insufficient stage information, the FIGO stage I-IV distributions were 196 (28.0%), 69 (9.9%), 175 (25.0%), and 260 (37.1%) patients, respectively. Overall survival for all patients at 5 years was 31%. Survival at 5 years by stage was I: 62%, II: 34%, III: 28%, and IV: 9%. Comparing radical surgery and definitive radiation therapy, there is no significant difference in 5 year overall survival for stage I (61% vs. 53%, P Z 0.27), II (48% vs. 28%, P Z 0.308) or III (33% vs. 28%, P Z 0.408) patients. EBRT + implant did not yield superior survival to EBRTalone in stage I (48% vs. 49% P Z 0.799), II (37% vs. 20% P Z 0.112) or III (25% vs. 32% P Z 0.636) patients. Multivariate Cox regression demonstrated that age (P Z 0.004) and stage (stage II: hazard ratio [HR] Z 1.78, P Z 0.013; stage III: HR Z 2.42 P<0.001) were independent factors impacting survival but not local treatment modality of surgery v. EBRT implant (EBRT: HR Z 1.30, P Z 0.17; EBRT + implant: HR Z 1.16, P Z 0.417). Conclusion: Patients with high-grade neuroendocrine cervical cancers have poor prognosis. Treatment by radical surgery or definitive radiation therapy with EBRT implant yields equally poor survival. Author Disclosure: W. Hou: None. T.E. Schultheiss: None. J.Y. Wong: None. M.T. Wakabayashi: None. Y. Chen: None.
2772 Early Outcomes and Dose-Volume Analysis for Patients With Cervical Cancer Treated With Computed Tomography-Based Treatment Planning in Brachytherapy A. Kawashima,1 F. Isohashi,2 S. Mabuchi,3 H. Okubo,1 K. Tamari,2 Y. Seo,2 O. Suzuki,2 Y. Yoshioka,2 T. Kimura,3 and K. Ogawa2;
Volume 96 Number 2S Supplement 2016 1
Department of Radiation Oncology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan, 2Osaka University, Suita, Osaka, Japan, 3 Department of Obstetrics and Gynecology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan Purpose/Objective(s): The aim of this study was to evaluate the early outcomes and dose-volume parameters of a computed tomography (CT)based image-guided brachytherapy (IGBT) technique for radical treatment of uterine cervical cancer. Materials/Methods: We retrospectively reviewed the medical records of 64 patients with stage IB1-IVA cervical cancer who underwent external beam radiation therapy (EBRT) and CT-based IGBT between February 2012 and March 2014. EBRT was delivered with three-dimensional conformal radiation therapy. The initial 30-40 Gy was delivered to the whole-pelvis and then pelvic irradiation with central shielding. Total pelvis side wall dose was 50 Gy in 25 fractions. Platinum-based chemotherapy was administered concurrently to 48 patients (75%). High-dose-rate IGBT was performed in 3-4 fractions during course of the EBRT with central shielding. A planning CT scan was obtained before the delivery of each brachytherapy fraction. The high-risk clinical target volume (HR-CTV) and organs at risk (rectum and bladder) were contoured on the planning CT. The basis for the treatment plan was the initial prescription to point A. After standard loading of the source, dwell times were modified manually to maximize coverage of the HR-CTV while reducing the dose to the organs at risk. The dose constraints were D90 of the HR-CTV > 6 Gy, D2cc of the rectum < 7 Gy and D2cc of the bladder < 7 Gy. To determine the dose from the combined EBRT (whole pelvic irradiation dose excluding the fractions with central shielding) and brachytherapy, the total dose was calculated as the biologically equivalent dose expressed in 2-Gy fractions (EQD2). The relationships between the EQD2 and local control or complications were analyzed. Results: The median follow-up period was 24 months (range: 14-47 months). The median EQD2 to D90 of HR-CTV and D2cc of the rectum were 72.4 Gy (range: 56.4-100.5 Gy) and 60.9 Gy (range: 41.5-83.3 Gy), respectively. The 2-year overall survival rate, local control rate and progression-free survival rate were 97%, 89%, and 82%, respectively. Five patients (8%) experienced local recurrence and 11 patients (17%) experienced grade 1 rectal bleeding. No other grade 2 complications were observed. The incidence of local recurrence was significantly lower in patients with D90 of the HR-CTV 65 Gy vs. < 65 Gy. The incidence of grade 1 rectal bleeding was significantly higher in patients with D2cc of rectum 55 Gy vs. < 55 Gy. Conclusion: CT-based IGBT for cervical cancer achieved higher rates of local control with lower grade of complications. Dose-volume parameters exhibited significant relationships with early outcomes in CT-based IGBT. Author Disclosure: A. Kawashima: None. F. Isohashi: None. S. Mabuchi: None. H. Okubo: None. K. Tamari: None. Y. Seo: None. O. Suzuki: None. Y. Yoshioka: None. T. Kimura: None. K. Ogawa: None.
2773 The Pathologic and Treatment Factors Associated With Recurrence in Stage IA Serous Adenocarcinoma of the Uterus E. Donovan,1 L. Eiriksson,1 C. Reade,2 H. Kaur,1 S. Memon,2 G. Pond,1 L. Elit,2 and I. Kong2; 1McMaster, Hamilton, ON, Canada, 2McMaster University, Hamilton, ON, Canada Purpose/Objective(s): Serous adenocarcinoma is a rare aggressive histologic subtype of endometrial cancer with a high rate of recurrence and a poor prognosis even at early stages. The optimal approach to adjuvant treatment for early stage disease is unknown. Patients with endometrium limited disease and a complete lymphadenectomy are presumed to be at lower recurrence risk. We report on the pathologic and treatment characteristics of recurrent cases in a large cohort of serous endometrial cancer patients to investigate whether adjuvant therapy can be omitted in low risk cases. Materials/Methods: A retrospective chart review inclusive of all cases of “serous carcinoma” of the endometrium from 2000-2014 was completed. Patients with FIGO 2009 stage IA pure or mixed serous histology who had undergone total hysterectomy and bilateral salpingo-oophorectomy were
Poster Viewing E315 included. Kaplan-Meier estimates were calculated for overall survival (OS) and recurrence free survival (RFS) and hazard ratios for prognostic factors were calculated using Cox proportional hazards modeling. Results: There were 63 patients with FIGO Stage 1A disease. Median follow up was 30.2 months. Patients were observed (N Z 33) or received adjuvant treatment (chemotherapy plus brachytherapy N Z 21; chemotherapy alone N Z 7; or pelvic radiation therapy +/- chemotherapy N Z 2). Fifty-seven patients (80.2%) had pelvic lymphadenectomy (median 9 nodes). Thirty-two (32) patients had endometrium-confined disease. There were seven recurrences (11.1%), at a median of 11 months (range 8-35). At 2- and 5-years RFS was 89.3% and 85.8%; and OS was 92.7% and 87.6%, respectively. Of those patients observed, four (12.1%) developed recurrence, with 2 vaginal recurrences only. In patients with endometriumconfined disease 9% developed recurrence, none of whom received adjuvant therapy. Two of 29 patients treated with chemotherapy as a component of their adjuvant treatment developed recurrence (6.9%). The majority of patients who recurred had extrapelvic recurrence with or without locoregional recurrence (71.4%). More than half of patients who recurred did not have adequate pelvic lymph node assessment (4 of 7 cases). On multivariate analysis only presence of myometrial invasion (HR 1.41, P Z 0.63) and presence of lymphovascular invasion (HR 2.69, P Z 0.29) were associated with inferior RFS, however, these were not statistically significant. Conclusion: In our cohort of early stage serous endometrial cancers RFS and OS were inferior to those reported for patients with endometriod histology. Our study indicates the importance of adequate surgical staging in early stage disease and supports the use of combination chemotherapy and brachytherapy in adjuvant treatment, even in patients with endometrium-confined Stage 1A disease. Author Disclosure: E. Donovan: None. L. Eiriksson: None. C. Reade: None. H. Kaur: None. S. Memon: None. G. Pond: None. L. Elit: None. I. Kong: None.
2774 To Assess the Changes of Volume and Spatial Location of Target Area During Cone Beam Computed Tomography for Cervical Cancer W. Chen, P. Bai, J. Pan, X. Zheng, and Q. LI; Fujian Provincial Cancer Hospital, Teaching Hospital of Fujian Medical University, Fuzhou, China Purpose/Objective(s): To assess the changes in volume and spatial location of target area and surrounding organs during cone beam computed tomography (CBCT) for cervical cancer. Materials/Methods: Sixteen patients with cervical cancer were performed intensity-modulated radiation therapy using offline cone beam computed tomography (CBCT) weekly during chemo/radiation. CTV was contoured on the planning CT. Each CBCT was rigidly registered to the planning CT with respect to bony anatomy. A pelvic MRI scan was performed before the radiation therapy and during the radiation dose of 9Gy/5f, 18Gy/10f, 27Gy/15f, 36Gy/20f, and 48.6Gy/27f. Those MRI images were compared with the first CT image, respectively. Changes of the target volume and spatial location were analyzed and evaluated for each patient by volume difference method and DICE similarity method. Results: The gross tumor volume (GTV-T) changed significantly from 79.62cm3 to 20.86cm3 (average 73.80%). The clinical target volume (CTV) changed slightly from 672.59 cm3 to 608.26cm3 (average 9.56%). The volume of Uterus (CTV-T) changed slightly from 83.72cm3 to 80.23cm3. GTV-T and CTV decreased gradually with the increase in the number of radiation, and the change of GTV-T was the most obvious. There was also significant difference in GTV-T and CTV-T among different groups (P<0.001), but CTV was not significantly different in volume (P>0.05) and the change of GTV-T had a linear correlation with the number of radiation therapy (P<0.001). The mean volume changed rate(delta V%) of GTV-T, CTV-T and CTV varied from 23.05%, 4.71% and 5.84% to 70.85%, 6.78% and 9.59%.There was significant difference in GTV-T among different groups (P<0.001),and the change of GTV-T had a linear correlation with the number of radiation therapy (P<0.001). There was a negative correlation between ¢V% and DSC in target area and organs at risk (r<0, P<0.05). The DICE similarity coefficient (DSC) of
International Journal of Radiation Oncology Biology Physics
Purpose/Objective(s): Pelvic sidewall dose from tandem and ring (TR) brachytherapy for cervical cancer is often used to approximate dose to the obturator and external iliac nodes, and determine the additional dose of EBRT needed for adequate control of any grossly involved nodes. However, previous published data have recommended caution when approximating sidewall dose in the era of image-guided brachytherapy utilizing volumetric planning. We performed a dosimetric analysis to specifically quantify sidewall dose in MRI-based TR brachytherapy. Materials/Methods: We evaluated 11 patients with cervical cancer treated with TR brachytherapy after completing a course of pelvic EBRT (45 Gy in 25 fractions). Foley catheter, vaginal packing, and a rectal retractor were used for all cases. Patients had stage I-III disease (5 stage I, 5 stage II, 1 stage III) without evidence of gross lymphadenopathy. All patients underwent CT simulation and MRI after applicator placement for treatment planning. High risk CTVs (HR-CTV) were delineated using T2-weighted MR sequences and organs at risk (OARs) using CT. Plans were generated for both insertions by manual optimization of dwell times. No sidewall dosimetry was incorporated in the optimization process. Twenty-eight Gy in 4 fractions was prescribed to D90 of the high risk CTV. Planning objectives (with dose contribution from EBRT) included: D90 HR-CTV Rx dose, D2cc rectum/sigmoid < 75 EQD2Gy, and D2cc bladder < 90 EQD2Gy. Sidewall calculations were performed on the axial mid-plane slice of the HR-CTV. Results: The median distance from the edge of the HR-CTV to the sidewall was 43.9 mm (range 35.8 e 50). The median distance from HR-CTV to the 50% IDL (approximately 60 Gy, by convention the dose to areas of initial parametrial involvement) was 24.5 mm (19.8 e 41.8). The median dose to the sidewall as a percentage of the Rx dose was 17.9% (8.2 - 21.6). For our dose fractionation, the absolute dose per fraction to the sidewall was 1.26 Gy (0.57 e 1.51). Conclusion: Dose to the pelvic sidewall using MR-based TR brachytherapy is variable and ranges from 8.2% to 21.58% of Rx dose (absolute dose 0.57 to 1.51 Gy per fraction) in this cohort. Patients with grossly involved pelvic nodes require individualized dosimetric evaluation when combining EBRT with image guided brachytherapy to avoid under-dosing nodal targets. Author Disclosure: M.Z. Kharouta: None. N. Sen: None. Y. Liao: None. D. Bernard: None. K.D. Kiel: None. J. Zhou: None.
rate, distant metastases rate, disease-specific survival rate, and treatmentrelated complications were compared between the two groups. Results: The median follow-up time was 38 months and the following rate was 96.1%. The surgery-based group resulted in comparable 3-years local recurrence rate (10.0% versus 12.1%, p Z 0. 47) to RT-based group. We found the 3-years disease-specific survival rate was higher for the RTbased group when compared with the surgery-based group (81.8% versus 60.0%, p Z 0.01). Moreover, the RT-based group also showed favorable results on the distant metastases rate (7.5% versus 40.0%, p Z 0.004) and the frequency of RTOG grade 3-4 late intestinal or urinary toxicities (6.1% versus 20.0%, p Z 0.006) comparing with the surgery-based group. Conclusion: Previous retrospective investigations showing the definitive chemo-radiation therapy was a superior approach than radical hysterectomy followed by postoperative radiation therapy with less treatmentrelated complications and favorable survival outcomes in patients with FIGO stage IIB cervical cancer. Author Disclosure: G. Cheng: None. M. He: None. H. Zhao: None. N. Zhang: None. Z. Yang: None. W. Yang: None.
2770 Radical Hysterectomy With Adjuvant Radiation Therapy Versus Definitive Radiation Therapy for International Federation of Gynecology and Obstetrics Stage IIb Cervical Cancer G. Cheng, M. He, H. Zhao, N. Zhang, Z. Yang, and W. Yang; Department of Radiation Oncology, China-Japan Union Hospital of Jilin University, Changchun, China Purpose/Objective(s): Cisplatin-based definitive chemo-radiation therapy was the primary treatment for FIGO stage IIB cervical cancer under the NCCN recommendation. However, in China, some patients with IIB stage after neoadjuvant chemotherapy have been subjected to radical hysterectomy. The aim of this study was to compare the treatment outcomes and adverse effects of radical hysterectomy followed by adjuvant radiation therapy with definitive chemo-radiation therapy in patients with FIGO stage IIB cervical cancer. Materials/Methods: We retrospectively reviewed the medical records of FIGO stage IIB cervical squamous cancer patients who were treated between October 2009 and January 2013. During the study period, 50 patients were treated with 2-3 cycles neoadjuvant chemotherapy, followed by radical hysterectomy and pelvic lymphadenectomy, all of the patients received the adjuvant external beam radiation therapy (EBRT) for 45-50.4 Gy in 25-28 fractions and three-dimensional high-dose-rate adaptive brachytherapy (3DHDR-ABT) for 10-20 Gy in 2-4 fractions weekly with or without adjuvant chemotherapy (surgery-based group). In addition, 66 patients received definitive chemo-radiation therapy consisted of pelvic EBRT for 45-50.4 Gy in 25-28 fractions plus concurrent platinum-based chemotherapy followed by 3D-HDR-ABT for 28 Gy in 4 fractions weekly (RT-based group). The patients were followed-up regularly in our institute. The local recurrence
2771 Surgery Versus Radiation Treatment for High-Grade Neuroendocrine Cancer of Uterine Cervix W.H. Hou,1 T.E. Schultheiss,2 J.Y.C. Wong,1 M.T. Wakabayashi,3 and Y.J. Chen1; 1Department of Radiation Oncology, City of Hope National Medical Center, Duarte, CA, 2Division of Physics, Department of Radiation Oncology, City of Hope National Medical Center, Duarte, CA, 3 Division of Gynecologic Oncology, Department of Surgery, City of Hope National Medical Center, Duarte, CA Purpose/Objective(s): To assess treatment and other factors impacting survival in high-grade neuroendocrine cervical carcinoma. Materials/Methods: We identified patients with high-grade neuroendocrine cervical cancers that were diagnosed during 1988-2012 in the Surveillance Epidemiology and End Results (SEER) database. We employed Kaplan-Meier analysis with log-rank test to determine and compare the overall survival by FIGO stages and by local treatment modalities (radical surgery and external beam radiation therapy (EBRT) with or without brachytherapy). We used proportional hazard analysis to determine the influence of age, stage and treatment modality on survival. Results: We identified a total of 832 cases of high-grade neuroendocrine cervical cancers. Mean age was 49.5 years old (range 19 to 95). After excluding the cases with insufficient stage information, the FIGO stage I-IV distributions were 196 (28.0%), 69 (9.9%), 175 (25.0%), and 260 (37.1%) patients, respectively. Overall survival for all patients at 5 years was 31%. Survival at 5 years by stage was I: 62%, II: 34%, III: 28%, and IV: 9%. Comparing radical surgery and definitive radiation therapy, there is no significant difference in 5 year overall survival for stage I (61% vs. 53%, P Z 0.27), II (48% vs. 28%, P Z 0.308) or III (33% vs. 28%, P Z 0.408) patients. EBRT + implant did not yield superior survival to EBRTalone in stage I (48% vs. 49% P Z 0.799), II (37% vs. 20% P Z 0.112) or III (25% vs. 32% P Z 0.636) patients. Multivariate Cox regression demonstrated that age (P Z 0.004) and stage (stage II: hazard ratio [HR] Z 1.78, P Z 0.013; stage III: HR Z 2.42 P<0.001) were independent factors impacting survival but not local treatment modality of surgery v. EBRT implant (EBRT: HR Z 1.30, P Z 0.17; EBRT + implant: HR Z 1.16, P Z 0.417). Conclusion: Patients with high-grade neuroendocrine cervical cancers have poor prognosis. Treatment by radical surgery or definitive radiation therapy with EBRT implant yields equally poor survival. Author Disclosure: W. Hou: None. T.E. Schultheiss: None. J.Y. Wong: None. M.T. Wakabayashi: None. Y. Chen: None.
2772 Early Outcomes and Dose-Volume Analysis for Patients With Cervical Cancer Treated With Computed Tomography-Based Treatment Planning in Brachytherapy A. Kawashima,1 F. Isohashi,2 S. Mabuchi,3 H. Okubo,1 K. Tamari,2 Y. Seo,2 O. Suzuki,2 Y. Yoshioka,2 T. Kimura,3 and K. Ogawa2;
Volume 96 Number 2S Supplement 2016 1
Department of Radiation Oncology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan, 2Osaka University, Suita, Osaka, Japan, 3 Department of Obstetrics and Gynecology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan Purpose/Objective(s): The aim of this study was to evaluate the early outcomes and dose-volume parameters of a computed tomography (CT)based image-guided brachytherapy (IGBT) technique for radical treatment of uterine cervical cancer. Materials/Methods: We retrospectively reviewed the medical records of 64 patients with stage IB1-IVA cervical cancer who underwent external beam radiation therapy (EBRT) and CT-based IGBT between February 2012 and March 2014. EBRT was delivered with three-dimensional conformal radiation therapy. The initial 30-40 Gy was delivered to the whole-pelvis and then pelvic irradiation with central shielding. Total pelvis side wall dose was 50 Gy in 25 fractions. Platinum-based chemotherapy was administered concurrently to 48 patients (75%). High-dose-rate IGBT was performed in 3-4 fractions during course of the EBRT with central shielding. A planning CT scan was obtained before the delivery of each brachytherapy fraction. The high-risk clinical target volume (HR-CTV) and organs at risk (rectum and bladder) were contoured on the planning CT. The basis for the treatment plan was the initial prescription to point A. After standard loading of the source, dwell times were modified manually to maximize coverage of the HR-CTV while reducing the dose to the organs at risk. The dose constraints were D90 of the HR-CTV > 6 Gy, D2cc of the rectum < 7 Gy and D2cc of the bladder < 7 Gy. To determine the dose from the combined EBRT (whole pelvic irradiation dose excluding the fractions with central shielding) and brachytherapy, the total dose was calculated as the biologically equivalent dose expressed in 2-Gy fractions (EQD2). The relationships between the EQD2 and local control or complications were analyzed. Results: The median follow-up period was 24 months (range: 14-47 months). The median EQD2 to D90 of HR-CTV and D2cc of the rectum were 72.4 Gy (range: 56.4-100.5 Gy) and 60.9 Gy (range: 41.5-83.3 Gy), respectively. The 2-year overall survival rate, local control rate and progression-free survival rate were 97%, 89%, and 82%, respectively. Five patients (8%) experienced local recurrence and 11 patients (17%) experienced grade 1 rectal bleeding. No other grade 2 complications were observed. The incidence of local recurrence was significantly lower in patients with D90 of the HR-CTV 65 Gy vs. < 65 Gy. The incidence of grade 1 rectal bleeding was significantly higher in patients with D2cc of rectum 55 Gy vs. < 55 Gy. Conclusion: CT-based IGBT for cervical cancer achieved higher rates of local control with lower grade of complications. Dose-volume parameters exhibited significant relationships with early outcomes in CT-based IGBT. Author Disclosure: A. Kawashima: None. F. Isohashi: None. S. Mabuchi: None. H. Okubo: None. K. Tamari: None. Y. Seo: None. O. Suzuki: None. Y. Yoshioka: None. T. Kimura: None. K. Ogawa: None.
2773 The Pathologic and Treatment Factors Associated With Recurrence in Stage IA Serous Adenocarcinoma of the Uterus E. Donovan,1 L. Eiriksson,1 C. Reade,2 H. Kaur,1 S. Memon,2 G. Pond,1 L. Elit,2 and I. Kong2; 1McMaster, Hamilton, ON, Canada, 2McMaster University, Hamilton, ON, Canada Purpose/Objective(s): Serous adenocarcinoma is a rare aggressive histologic subtype of endometrial cancer with a high rate of recurrence and a poor prognosis even at early stages. The optimal approach to adjuvant treatment for early stage disease is unknown. Patients with endometrium limited disease and a complete lymphadenectomy are presumed to be at lower recurrence risk. We report on the pathologic and treatment characteristics of recurrent cases in a large cohort of serous endometrial cancer patients to investigate whether adjuvant therapy can be omitted in low risk cases. Materials/Methods: A retrospective chart review inclusive of all cases of “serous carcinoma” of the endometrium from 2000-2014 was completed. Patients with FIGO 2009 stage IA pure or mixed serous histology who had undergone total hysterectomy and bilateral salpingo-oophorectomy were
Poster Viewing E315 included. Kaplan-Meier estimates were calculated for overall survival (OS) and recurrence free survival (RFS) and hazard ratios for prognostic factors were calculated using Cox proportional hazards modeling. Results: There were 63 patients with FIGO Stage 1A disease. Median follow up was 30.2 months. Patients were observed (N Z 33) or received adjuvant treatment (chemotherapy plus brachytherapy N Z 21; chemotherapy alone N Z 7; or pelvic radiation therapy +/- chemotherapy N Z 2). Fifty-seven patients (80.2%) had pelvic lymphadenectomy (median 9 nodes). Thirty-two (32) patients had endometrium-confined disease. There were seven recurrences (11.1%), at a median of 11 months (range 8-35). At 2- and 5-years RFS was 89.3% and 85.8%; and OS was 92.7% and 87.6%, respectively. Of those patients observed, four (12.1%) developed recurrence, with 2 vaginal recurrences only. In patients with endometriumconfined disease 9% developed recurrence, none of whom received adjuvant therapy. Two of 29 patients treated with chemotherapy as a component of their adjuvant treatment developed recurrence (6.9%). The majority of patients who recurred had extrapelvic recurrence with or without locoregional recurrence (71.4%). More than half of patients who recurred did not have adequate pelvic lymph node assessment (4 of 7 cases). On multivariate analysis only presence of myometrial invasion (HR 1.41, P Z 0.63) and presence of lymphovascular invasion (HR 2.69, P Z 0.29) were associated with inferior RFS, however, these were not statistically significant. Conclusion: In our cohort of early stage serous endometrial cancers RFS and OS were inferior to those reported for patients with endometriod histology. Our study indicates the importance of adequate surgical staging in early stage disease and supports the use of combination chemotherapy and brachytherapy in adjuvant treatment, even in patients with endometrium-confined Stage 1A disease. Author Disclosure: E. Donovan: None. L. Eiriksson: None. C. Reade: None. H. Kaur: None. S. Memon: None. G. Pond: None. L. Elit: None. I. Kong: None.
2774 To Assess the Changes of Volume and Spatial Location of Target Area During Cone Beam Computed Tomography for Cervical Cancer W. Chen, P. Bai, J. Pan, X. Zheng, and Q. LI; Fujian Provincial Cancer Hospital, Teaching Hospital of Fujian Medical University, Fuzhou, China Purpose/Objective(s): To assess the changes in volume and spatial location of target area and surrounding organs during cone beam computed tomography (CBCT) for cervical cancer. Materials/Methods: Sixteen patients with cervical cancer were performed intensity-modulated radiation therapy using offline cone beam computed tomography (CBCT) weekly during chemo/radiation. CTV was contoured on the planning CT. Each CBCT was rigidly registered to the planning CT with respect to bony anatomy. A pelvic MRI scan was performed before the radiation therapy and during the radiation dose of 9Gy/5f, 18Gy/10f, 27Gy/15f, 36Gy/20f, and 48.6Gy/27f. Those MRI images were compared with the first CT image, respectively. Changes of the target volume and spatial location were analyzed and evaluated for each patient by volume difference method and DICE similarity method. Results: The gross tumor volume (GTV-T) changed significantly from 79.62cm3 to 20.86cm3 (average 73.80%). The clinical target volume (CTV) changed slightly from 672.59 cm3 to 608.26cm3 (average 9.56%). The volume of Uterus (CTV-T) changed slightly from 83.72cm3 to 80.23cm3. GTV-T and CTV decreased gradually with the increase in the number of radiation, and the change of GTV-T was the most obvious. There was also significant difference in GTV-T and CTV-T among different groups (P<0.001), but CTV was not significantly different in volume (P>0.05) and the change of GTV-T had a linear correlation with the number of radiation therapy (P<0.001). The mean volume changed rate(delta V%) of GTV-T, CTV-T and CTV varied from 23.05%, 4.71% and 5.84% to 70.85%, 6.78% and 9.59%.There was significant difference in GTV-T among different groups (P<0.001),and the change of GTV-T had a linear correlation with the number of radiation therapy (P<0.001). There was a negative correlation between ¢V% and DSC in target area and organs at risk (r<0, P<0.05). The DICE similarity coefficient (DSC) of