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51 poster review High-dose-rate brachytherapy (HDR-BT) of tongue base tumours
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Saturday, 17 May 2003
Poster Review FREE COMMUNICATIONS 48
poster review
Factors correlated with late rectal and bladder morbidity in definitive radiation therapy of carcinoma of the cervix S~ Kim 1, H. Kim 1, J. Kim 1, K. Kim 1, S. Hong 1, W. Kang 1, H. Wu 1,2, I. Kim 1,2, S. Ha 1,2, C. Park 1,2 1Seoul National University College of Medicine, Therapeutic Radiology, Seoul, Korea 2Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea Purpose: To analyse the impact of various host-related and treatment-related factors on late rectal and bladder morbidity in patients treated with irradiation alone for cervix cancer. Methods and Materials: Late rectal and bladder morbidity were evaluated according to the RTOG criteria in 54 patients with stage IB-IVA cervical cancer who were treated by external beam radiotherapy followed by intracavitary brachytherapy in our department between January 1996 and December 1999. All patients were followed up for more than 24 months. EBRT was delivered with 1.8 Gy daily fractions to a dose of 5040 cGy followed by ICRT with total point A doses ranging from 7500 cGy to 8500 cGy. Most patients were treated with dose rate 50 - 70 Gy/h to iCRU reference point A, but eight patient were treated with higher dose rate (0.83 - 11.5 Gy/h) to shorten the hospital day. Biologically equivalent doses (BED) for the reference points were calculated using a linear quadratic model. Acturial rate of late morbidity was (~alculated by Kaplan-Meier method. Results: The late rectal morbidity was developed in 23 patients (43%). Eight patients had grade 1, 11 had grade 2, and 4 had grade 3 morbidity by RTOG criteria. The late bladder morbidity was developed in 10 patients (19%). Six patients had grade 1, 3 had grade 2, and 1 had grade 3. Acturial estimates at 2 years showed 47% late rectal and 14% late bladder morbidity rate. In the rectum, the accumulated incidence of late morbidity at 2 years was 58% in patients with age more than 60 years than and 20% in patients less than 60 (p=0.01). Doses more than 80 Gy to rectal point correlated with 83% incidence of morbidity and 42% with lower doses (p=0.03). Dose rate and BED of rectal point were not statistically significant factors for late rectal morbidity. In the bladder, doses more than 80 Gy to bladder point correlated with 25% incidence of morbidity and 11% with lower doses (p=0.04). Dose rate more than 75 Gy/h (p=0.03) and BED more than 200 Gy (p=0.01) to bladder point were significant factors for late bladder morbidity. FIGO Stage, total dose, dose rate and BED of point A were not significant factors for estimating late rectal and bladder morbidity rates. Conclusion: Age and total rectal point dose correlated with higher rate of late rectal morbidity. Total dose, dose rate and BED of bladder point significantly correlated with the incidence of late bladder morbidity. 49
poster review
Anxiety and depression in women receiving brachytherapy for gynecologic cancer. A randomized study. C. Leon, A. Rovirosa, S. Jorcano, I. Toscas, J. Fernandez, A. Biete Hospital Clinic, Radiotherapy, Barcelona, Spain Introduction: Cancer patients often have to deal with side effects and psychological distress during cancer treatment. The discomfort that women experience during brachytherapy is characterized by an intense tension and fear, due in part by the isolation, prohibition of visits, bed confinement, restriction of movements, use of the intracavitary system, measures of radiological protection, use of a bladder tube, and difficulty in personal hygiene. Among psychosocial interventions for reducing treatment-related stress effects, relaxation and imagery were most useful. PurDose of the studv: The aim of this study was to gather information about the effectiveness .of a specific behavioral intervention in reducing psychological distress in women receiving brachytherapy for gynecologic cancer. Description of the project: Participants were recruited from the Radiotherapy Dpt. All of them received brachytherapy for gynecological cancer. The
patients were randomized into an intervention group and a control group. Psychological intervention of a modified form of Jacobson's method for progressive muscle relaxation and guided imagery, was taught to the patients of the intervention group. Quality of Life and their psychological status, according to the Hospital Anxiety and Depression Scale (HADS), were evaluated three times: before, during and after the in-patient period in all patients participating in the study. Re_suits: Quality of life during the in-patient period and HADS showed better results for the patients of the intervention group. More detailed data will be presented Conclusions: The preliminary data show that women receiving brachytherapy for gynecological cancer seem to benefit from the psychological intervention reducing stress symptoms. This study was supported by a grant from the Asociacion Espanola Contra el Cancer (AECC). Junta Provincial de las Comarcas Barceloninas. 50
poster review
High-dose rate brachytherapy alone post-hysterectomy for endometrial carcinoma M. Jorge, I. Monteiro Grille. M. Ortiz, O. Abad, F~ Marques Hospital de Santa Maria, Radiotherapy Department, Lisboa, Portugal Puroose: To evaluate local control, toxicity and survival among patients (pts) with endometrial carcinoma stage I and II submitted to post-hysterectomy adjuvant high-dose-rate (HDR) intravaginal brachytherapy (IVBT). Methods and Materials: Between April 1997 to December 2001, pts with endometrial adenocarcinoma stage I and II undergoing total hysterectomy with bilateral salpingo-ooforectomy including negative lymphadenectomy were submitted to tVBT (HDR) as exclusive adjuvant therapy. The study group consisted in 71 patients with a median age of 64 (43-85) years. The distribution of pts by stage (1988 FIGO classification ) and histologic grade was the following: pT1b/G1-42 pts, pT1b/G2-18 pts, pTlb/G3-1 pts; pTlciG2-4 pts, pTlc/G3-2 pts; pT2a/G1-3 pts; pT2b/G3-t pts. Vaginal brachytherapy was given in 4 weekly fractions of 6 Gy, prescribed at 5 mm depth from the applicator surface. Toxicity was evaluated according to EORTC/RTOG scale. Results: With a median follow-up time of 34 (12-68) months, 70 pts are alive and one patient died with breast cancer without evidence of disease. The 5 years overall survival and disease free survival probability was 9&5% and 93.4% respectively. Recurrence was observed in four pts (5,5%) during the first 2 years: 1 pt experienced low vaginal recurrence concomitantly with positive femoral nodes and was submitted to external beam radiotherapy (EBRT), 2 pts developed a pelvic mass and were submited to surgery followed by EBRT, and 1 pt developed peritoneal carcinomatosis, after 11,6,15 and 14 months respectively. The overall late-toxicity rate was low and no grade 3 or 4 complications were recorded. Conclusion: Pos-operative intravaginal brachytherapy in pts with surgical stage I and II endometrial carcinoma achieve excellent local control and minimal morbidity. 51
poster review
High-dose-rate brachytherapy (HDR-BT) of tongue base tumours Z. Takacsi-Naov I C. Polgar 1, F. Oberna 2, A. Somogyi 1, T. Major 1, J. Fodor 1, M. Kasler 3, G. Nemeth 3 1National Institute of Oncology, Dept.of Radiotherapy, Budapest, Hungary 2National Institute of Oncology, Dept.of Head and Neck Surgery, Budapest, Hungary 3Semmelweis University, Chair of Oncology, Budapest, Hungary Introduction: The purpose of this retrospective study is to present the results of interstitial HDR-BT for carcinoma of the tongue base. Material and methods: Between January 1992 and June 2000 thirty-seven patients (26 men and 11 women) with primary squamous cell (n=35) or adenoid cystic (n=2) carcinoma of the base of tongue (T1-4N0-3) were treated by interstitial HDR radiotherapy. Age ranged from 36-74 years (mean, 56
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years).The T-status was: T1,4; T2, 5; T3, 14; T4, 14. Eighteen patients (49 %) were initially seen with nodal metastases. Thirty patients with advanced stage received BT boost after 50-66 Gy (mean, 60 Gy) external beam irradiation (EBI) and 7 patients with early stage/T1-2N0, exophytic (n=6) or infiltrating type (n=l)/ were managed by sole BT after tumour excision. Implantation was carried out with flexible plastic tubes (n=27) or rigid needles (n=10). Treatment planning was performed using the PLATO 3D BT software. The mean dose of boost BT or sole BT was 20 Gy (10-30 Gy) and 27 Gy (24-30 Gy), respectively. The median follow-up time for surviving patients was 50 months (range 21-108). Results: For all patients the 2- and 5-year actuarial local control, locoregional control, and overall survival was 61% and 51%, 51% and 42 %, and 67 % and 62 %, respectively. All sole BT patients are living with no evidence of disease. Osteoradionecrosis developed only in one patient (3 %) in the boost HeR BT group. Conclusions: Our results indicate that EBI followed by interstitial BT can result acceptable local tumour control with minimal side-effect. For early stage, exophytic base of tongue cancer sole postoperative BT of the tumour bed seems to be a feasible option with excellent results. However more studies are needed to define the value of sole BT of the primary after resection. 52
poster review
Brachytherapy alone for T1-T2 NO squamous cell carcinomas of the velotonsillar area : results in 36 cases. S~ ...Clioee,P. Pommier, X Montbarbon Centre L6on Berard, Radiotherapy, Lyon, France Purpose: To evaluate carcinologic results of the treatment of vetotonsillar carcinomas by interstitial brachytherapy alone. Methods and Materials: We studied patients presenting with velotonsillar squamous cell carcinoma between July 1992 and April 2000, treated at Centre Leon Berard with brachytherapy alone using an 1921r implant (afterloading technique) with curative intent. Results: According to the UICC 1997 TNM classification, there were 21 T1N0, 2 T1N2, 1 T1Nx, 11 T2N0 and 1 T2NI. The median age was 57 years (40-83). Four patients were females and 32 were males. Nine had prior radiotherapy (median dose 60 Gy) for a previous head and neck carcinoma. The brachytherapy median dose was 60 Gy (median linear activity: 1.49 mCi/cm; median reference dose rate: 58.6 cGy per hour). The median follow-up was 48 months (0-115). The 5-year actuarial overall survival rate was 88%. The 5-year actuarial relapse-free survival rate was 85%. Four failures (all Ioco-regional) occurred at a median time of 21 months (1044): 2 patients died due to their recurrence, 1 due to intercurrent disease (brain stroke) and the fourth is alive 7 years after salvage therapy (node dissection + radiotherapy). None of the 4 patients who relapsed had initial lymph node dissection. Nine patients developed second head and neck malignancies. No complications were reported. Conclusion: Brachytherapy alone is an effective treatment for patients with velotonsillar carcinoma either in previously irradiated field or not. Initial cervical lymph node dissection should be performed for an optimal selection for brachytherapy alone. This study also focuses on the problem of second head and neck primary tumors. 53
poster review
Preservation of the parotids for oropharyngeal carcinoma: a comparison between 3 boost modalities: brachytherapy (BT), Intensity-Modulated Radiation Therapy (IMRT) and Three Dimensional Conformal Radiotherapy (3D-CRT) M. Laoeyre, S. Racadot, V. Marchesi, F. Ahmad, M. Bollet, P. Graft, A. Noel, C. Marchal, P. Aletti, S. Hoffstetter, D. Peiffert Radiotherapy Department, Centre Alexis Vautrin, 54511 Vandoeuvre-lesNancy, France Introduction: to report the dose distributions to the parotids and the oral cavity for 3 boost modalities to an early staged (T1 NO) medial velo-tonsillar carcinoma (BT vs IMRT vs 3D-CRT). Material and methods: the patient underwent a first step of radiotherapy with a mean dose of 50.3 Gy to the PTV (NO and T) with dynamic IMRT (Helios, Clinac EX 23, Varian). The mean doses to the right and left parotids were 31.7 and 32 Gy, and to the oral cavity 35 Gy. The boost (25 Gy on the reference isodose) was delivered by interstitial BT with 2 loops implanted into the velo-tonsillar region using low-dose-rate iridium sources with manual afterloading (Paris System). Dose distributions were compared between the 3 boost modalities i.e. BT (Plato-BPS, Nucletron), optimised 4-field 3D-CRT (Cadplan TPS, Varian) and a non-opposed 4-field
Poster review
IMRT (Helios, Varian). In the case of 3D-CRT or IMRT, the prescribed dose was 20 Gy (ICRU). Results: the mean dose to the PTV was 19.6 Gy for 3D-CRT and 20 Gy for IMRT. The conformation number for 95% PTV (Van't Riet) was respectively 0.57 and 0.63. The irradiated volume (10 Gy) was 266 cc for 3D-CRT, 206 cc for tMRT and 117 cc for BT. The mean right parotid dose was respectively 6.7 Gy, 6 Gy and 1.78 Gy. The mean left parotid dose was respectively 5.1 Gy, 5.8 Gy and 1.78 Gy. The mean dose to the oral cavity was respectively 7.1 Gy, 4.9 Gy and 5.9 Gy. _Conclusion: BT resulted in lower mean dose to the parotids and smaller irradiated volume as compared to IMRT and 3D-CRT. Compared to 3D-CRT, IMRT resulted in a better dose distribution to the PTV while sparing the oral cavity but with comparable dose distributions to the parotids. 54
poster review
Effects of continuous low dose rate (CLDR) and pulsed dose rate (PDR) brachytherapy on cell cycle progression in a syngeneic tumor model W. Harms 1, P. Peschke 2, K. Weber 1, V. Ehemann 3, J. Debus 1, M.F. Wannenmacher 1 1University of Heidelberg, Clinical Radiology, Radiation Therapy, Heidelberg, Germany 2German Cancer Research Center, Radiation Therapy, Heidelberg, Germany 3University of Heidelberg, Pathology, Heidelberg, Germany Aim: The aim of this study was to investigate the effects of interstitial CLDR and PDR brachytherapy on ploidy and cell cycle distribution in a syngeneic rat prostate tumor model. Methods: Interstitial PDR and CLDR brachytherapy were administered to the Dunning prostate R3327-AT1 carcinoma transplanted subcutaneously into the right thigh of Copenhagen rats. A dose of 20 and 40 Gy was administered in each study arm (CLDR versus PDR). 3 animals were irradiated per dose group, exposure condition, and dose group. Interstitial PDR was carried out using a 37 GBq 1921r source with 0,75 Gy/pulse and hour. CLDR was administered with a centrally implanted seed with a dose rate of 0,75 Gy/h. The dose was prescribed to the tumor surface (5 mm source distance, tumor diameter 10 mm). Flow cytometric measurements (n=3-5) were performed 4, 24, 48, 72, 96, and 120 h after the initiation of brachytherapy. Results: The following median percentages of diploid and aneuploid (in brackets) tumor cell fractions at 4, 24, 48, 72, 96, and 120 h were measured:CLDR 20 Gy (%): 86 (14), 69 (29), 62 (38), 78 (22), 70 (27), 85 (2)PDR 20 Gy (%): 77 (19), 67 (26), 70 (22), 63 (39), 69 (31), 70 (10)CLDR 40 Gy (%): 90 (10), 65 (35), 79 (21), 79 (21), 75 (25), 85 (15)PDR 40 Gy (%): 79 (21), 76 (21), 80 (20), 76 (24), 92 (8), 95 (5). Additionally, the cell cycle distribution was compared in the different treatment and dose groups. Conclusion: As a first result of these flow cytometric measurements, CLDR and PDR brachytherapy showed no differential effects on cell cycle distribution and ploidy. 55
poster review
Precision and dose conformation in the CT-based reconstruction of interstitial brachytherapy F.W. Henslev I W. Harms 1, R. Krempien 1, P. Fritz2, M. Wannenmacher 1 1Un iversity Cfinics, Ruprecht Karl University Heide, Dept. of Radiotherapy, Heidelberg, Germany 2St. Marien-Krankenhaus , Dept.of Radiooncology, Siegen, Germany Puroose: CT-based reconstruction of brachytherapy implants and applicators introduces major improvements in conformal brachytherapy. However, the precision of CT reconstruction is restricted by a number of uncertainties. This includes patient movement during the longer duration of the scan session, but also mislocations produced by the finite thickness and distance of the CT slices. Further uncertainties are introduced by CT resolution, artifacts, image distortion, and also by imperfections in the computer-user interface. Aim of this work is to assess the geometrical uncertainties of CTbasesd reconstruction and their impact on target volume definition and the resulting distortion of the dose distribution. Materials and methods: Both radiograph and CT reconstructions were performed for a phantom and for a series of 33 patients with interstitial breast implants. CT studies were aquired for slice distances of 1.5, 2, 3, and 5ram. After transformation of both reconstructions to an identical coordinate system, the geometrical distances between corresponding dwell positions were determined. Histograms were calculated showing the distribution of shifts in three coordinates. The standard deviation of the histograms is taken as
Saturday, 17 May 2003
Poster Review FREE COMMUNICATIONS 48
poster review
Factors correlated with late rectal and bladder morbidity in definitive radiation therapy of carcinoma of the cervix S~ Kim 1, H. Kim 1, J. Kim 1, K. Kim 1, S. Hong 1, W. Kang 1, H. Wu 1,2, I. Kim 1,2, S. Ha 1,2, C. Park 1,2 1Seoul National University College of Medicine, Therapeutic Radiology, Seoul, Korea 2Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea Purpose: To analyse the impact of various host-related and treatment-related factors on late rectal and bladder morbidity in patients treated with irradiation alone for cervix cancer. Methods and Materials: Late rectal and bladder morbidity were evaluated according to the RTOG criteria in 54 patients with stage IB-IVA cervical cancer who were treated by external beam radiotherapy followed by intracavitary brachytherapy in our department between January 1996 and December 1999. All patients were followed up for more than 24 months. EBRT was delivered with 1.8 Gy daily fractions to a dose of 5040 cGy followed by ICRT with total point A doses ranging from 7500 cGy to 8500 cGy. Most patients were treated with dose rate 50 - 70 Gy/h to iCRU reference point A, but eight patient were treated with higher dose rate (0.83 - 11.5 Gy/h) to shorten the hospital day. Biologically equivalent doses (BED) for the reference points were calculated using a linear quadratic model. Acturial rate of late morbidity was (~alculated by Kaplan-Meier method. Results: The late rectal morbidity was developed in 23 patients (43%). Eight patients had grade 1, 11 had grade 2, and 4 had grade 3 morbidity by RTOG criteria. The late bladder morbidity was developed in 10 patients (19%). Six patients had grade 1, 3 had grade 2, and 1 had grade 3. Acturial estimates at 2 years showed 47% late rectal and 14% late bladder morbidity rate. In the rectum, the accumulated incidence of late morbidity at 2 years was 58% in patients with age more than 60 years than and 20% in patients less than 60 (p=0.01). Doses more than 80 Gy to rectal point correlated with 83% incidence of morbidity and 42% with lower doses (p=0.03). Dose rate and BED of rectal point were not statistically significant factors for late rectal morbidity. In the bladder, doses more than 80 Gy to bladder point correlated with 25% incidence of morbidity and 11% with lower doses (p=0.04). Dose rate more than 75 Gy/h (p=0.03) and BED more than 200 Gy (p=0.01) to bladder point were significant factors for late bladder morbidity. FIGO Stage, total dose, dose rate and BED of point A were not significant factors for estimating late rectal and bladder morbidity rates. Conclusion: Age and total rectal point dose correlated with higher rate of late rectal morbidity. Total dose, dose rate and BED of bladder point significantly correlated with the incidence of late bladder morbidity. 49
poster review
Anxiety and depression in women receiving brachytherapy for gynecologic cancer. A randomized study. C. Leon, A. Rovirosa, S. Jorcano, I. Toscas, J. Fernandez, A. Biete Hospital Clinic, Radiotherapy, Barcelona, Spain Introduction: Cancer patients often have to deal with side effects and psychological distress during cancer treatment. The discomfort that women experience during brachytherapy is characterized by an intense tension and fear, due in part by the isolation, prohibition of visits, bed confinement, restriction of movements, use of the intracavitary system, measures of radiological protection, use of a bladder tube, and difficulty in personal hygiene. Among psychosocial interventions for reducing treatment-related stress effects, relaxation and imagery were most useful. PurDose of the studv: The aim of this study was to gather information about the effectiveness .of a specific behavioral intervention in reducing psychological distress in women receiving brachytherapy for gynecologic cancer. Description of the project: Participants were recruited from the Radiotherapy Dpt. All of them received brachytherapy for gynecological cancer. The
patients were randomized into an intervention group and a control group. Psychological intervention of a modified form of Jacobson's method for progressive muscle relaxation and guided imagery, was taught to the patients of the intervention group. Quality of Life and their psychological status, according to the Hospital Anxiety and Depression Scale (HADS), were evaluated three times: before, during and after the in-patient period in all patients participating in the study. Re_suits: Quality of life during the in-patient period and HADS showed better results for the patients of the intervention group. More detailed data will be presented Conclusions: The preliminary data show that women receiving brachytherapy for gynecological cancer seem to benefit from the psychological intervention reducing stress symptoms. This study was supported by a grant from the Asociacion Espanola Contra el Cancer (AECC). Junta Provincial de las Comarcas Barceloninas. 50
poster review
High-dose rate brachytherapy alone post-hysterectomy for endometrial carcinoma M. Jorge, I. Monteiro Grille. M. Ortiz, O. Abad, F~ Marques Hospital de Santa Maria, Radiotherapy Department, Lisboa, Portugal Puroose: To evaluate local control, toxicity and survival among patients (pts) with endometrial carcinoma stage I and II submitted to post-hysterectomy adjuvant high-dose-rate (HDR) intravaginal brachytherapy (IVBT). Methods and Materials: Between April 1997 to December 2001, pts with endometrial adenocarcinoma stage I and II undergoing total hysterectomy with bilateral salpingo-ooforectomy including negative lymphadenectomy were submitted to tVBT (HDR) as exclusive adjuvant therapy. The study group consisted in 71 patients with a median age of 64 (43-85) years. The distribution of pts by stage (1988 FIGO classification ) and histologic grade was the following: pT1b/G1-42 pts, pT1b/G2-18 pts, pTlb/G3-1 pts; pTlciG2-4 pts, pTlc/G3-2 pts; pT2a/G1-3 pts; pT2b/G3-t pts. Vaginal brachytherapy was given in 4 weekly fractions of 6 Gy, prescribed at 5 mm depth from the applicator surface. Toxicity was evaluated according to EORTC/RTOG scale. Results: With a median follow-up time of 34 (12-68) months, 70 pts are alive and one patient died with breast cancer without evidence of disease. The 5 years overall survival and disease free survival probability was 9&5% and 93.4% respectively. Recurrence was observed in four pts (5,5%) during the first 2 years: 1 pt experienced low vaginal recurrence concomitantly with positive femoral nodes and was submitted to external beam radiotherapy (EBRT), 2 pts developed a pelvic mass and were submited to surgery followed by EBRT, and 1 pt developed peritoneal carcinomatosis, after 11,6,15 and 14 months respectively. The overall late-toxicity rate was low and no grade 3 or 4 complications were recorded. Conclusion: Pos-operative intravaginal brachytherapy in pts with surgical stage I and II endometrial carcinoma achieve excellent local control and minimal morbidity. 51
poster review
High-dose-rate brachytherapy (HDR-BT) of tongue base tumours Z. Takacsi-Naov I C. Polgar 1, F. Oberna 2, A. Somogyi 1, T. Major 1, J. Fodor 1, M. Kasler 3, G. Nemeth 3 1National Institute of Oncology, Dept.of Radiotherapy, Budapest, Hungary 2National Institute of Oncology, Dept.of Head and Neck Surgery, Budapest, Hungary 3Semmelweis University, Chair of Oncology, Budapest, Hungary Introduction: The purpose of this retrospective study is to present the results of interstitial HDR-BT for carcinoma of the tongue base. Material and methods: Between January 1992 and June 2000 thirty-seven patients (26 men and 11 women) with primary squamous cell (n=35) or adenoid cystic (n=2) carcinoma of the base of tongue (T1-4N0-3) were treated by interstitial HDR radiotherapy. Age ranged from 36-74 years (mean, 56
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years).The T-status was: T1,4; T2, 5; T3, 14; T4, 14. Eighteen patients (49 %) were initially seen with nodal metastases. Thirty patients with advanced stage received BT boost after 50-66 Gy (mean, 60 Gy) external beam irradiation (EBI) and 7 patients with early stage/T1-2N0, exophytic (n=6) or infiltrating type (n=l)/ were managed by sole BT after tumour excision. Implantation was carried out with flexible plastic tubes (n=27) or rigid needles (n=10). Treatment planning was performed using the PLATO 3D BT software. The mean dose of boost BT or sole BT was 20 Gy (10-30 Gy) and 27 Gy (24-30 Gy), respectively. The median follow-up time for surviving patients was 50 months (range 21-108). Results: For all patients the 2- and 5-year actuarial local control, locoregional control, and overall survival was 61% and 51%, 51% and 42 %, and 67 % and 62 %, respectively. All sole BT patients are living with no evidence of disease. Osteoradionecrosis developed only in one patient (3 %) in the boost HeR BT group. Conclusions: Our results indicate that EBI followed by interstitial BT can result acceptable local tumour control with minimal side-effect. For early stage, exophytic base of tongue cancer sole postoperative BT of the tumour bed seems to be a feasible option with excellent results. However more studies are needed to define the value of sole BT of the primary after resection. 52
poster review
Brachytherapy alone for T1-T2 NO squamous cell carcinomas of the velotonsillar area : results in 36 cases. S~ ...Clioee,P. Pommier, X Montbarbon Centre L6on Berard, Radiotherapy, Lyon, France Purpose: To evaluate carcinologic results of the treatment of vetotonsillar carcinomas by interstitial brachytherapy alone. Methods and Materials: We studied patients presenting with velotonsillar squamous cell carcinoma between July 1992 and April 2000, treated at Centre Leon Berard with brachytherapy alone using an 1921r implant (afterloading technique) with curative intent. Results: According to the UICC 1997 TNM classification, there were 21 T1N0, 2 T1N2, 1 T1Nx, 11 T2N0 and 1 T2NI. The median age was 57 years (40-83). Four patients were females and 32 were males. Nine had prior radiotherapy (median dose 60 Gy) for a previous head and neck carcinoma. The brachytherapy median dose was 60 Gy (median linear activity: 1.49 mCi/cm; median reference dose rate: 58.6 cGy per hour). The median follow-up was 48 months (0-115). The 5-year actuarial overall survival rate was 88%. The 5-year actuarial relapse-free survival rate was 85%. Four failures (all Ioco-regional) occurred at a median time of 21 months (1044): 2 patients died due to their recurrence, 1 due to intercurrent disease (brain stroke) and the fourth is alive 7 years after salvage therapy (node dissection + radiotherapy). None of the 4 patients who relapsed had initial lymph node dissection. Nine patients developed second head and neck malignancies. No complications were reported. Conclusion: Brachytherapy alone is an effective treatment for patients with velotonsillar carcinoma either in previously irradiated field or not. Initial cervical lymph node dissection should be performed for an optimal selection for brachytherapy alone. This study also focuses on the problem of second head and neck primary tumors. 53
poster review
Preservation of the parotids for oropharyngeal carcinoma: a comparison between 3 boost modalities: brachytherapy (BT), Intensity-Modulated Radiation Therapy (IMRT) and Three Dimensional Conformal Radiotherapy (3D-CRT) M. Laoeyre, S. Racadot, V. Marchesi, F. Ahmad, M. Bollet, P. Graft, A. Noel, C. Marchal, P. Aletti, S. Hoffstetter, D. Peiffert Radiotherapy Department, Centre Alexis Vautrin, 54511 Vandoeuvre-lesNancy, France Introduction: to report the dose distributions to the parotids and the oral cavity for 3 boost modalities to an early staged (T1 NO) medial velo-tonsillar carcinoma (BT vs IMRT vs 3D-CRT). Material and methods: the patient underwent a first step of radiotherapy with a mean dose of 50.3 Gy to the PTV (NO and T) with dynamic IMRT (Helios, Clinac EX 23, Varian). The mean doses to the right and left parotids were 31.7 and 32 Gy, and to the oral cavity 35 Gy. The boost (25 Gy on the reference isodose) was delivered by interstitial BT with 2 loops implanted into the velo-tonsillar region using low-dose-rate iridium sources with manual afterloading (Paris System). Dose distributions were compared between the 3 boost modalities i.e. BT (Plato-BPS, Nucletron), optimised 4-field 3D-CRT (Cadplan TPS, Varian) and a non-opposed 4-field
Poster review
IMRT (Helios, Varian). In the case of 3D-CRT or IMRT, the prescribed dose was 20 Gy (ICRU). Results: the mean dose to the PTV was 19.6 Gy for 3D-CRT and 20 Gy for IMRT. The conformation number for 95% PTV (Van't Riet) was respectively 0.57 and 0.63. The irradiated volume (10 Gy) was 266 cc for 3D-CRT, 206 cc for tMRT and 117 cc for BT. The mean right parotid dose was respectively 6.7 Gy, 6 Gy and 1.78 Gy. The mean left parotid dose was respectively 5.1 Gy, 5.8 Gy and 1.78 Gy. The mean dose to the oral cavity was respectively 7.1 Gy, 4.9 Gy and 5.9 Gy. _Conclusion: BT resulted in lower mean dose to the parotids and smaller irradiated volume as compared to IMRT and 3D-CRT. Compared to 3D-CRT, IMRT resulted in a better dose distribution to the PTV while sparing the oral cavity but with comparable dose distributions to the parotids. 54
poster review
Effects of continuous low dose rate (CLDR) and pulsed dose rate (PDR) brachytherapy on cell cycle progression in a syngeneic tumor model W. Harms 1, P. Peschke 2, K. Weber 1, V. Ehemann 3, J. Debus 1, M.F. Wannenmacher 1 1University of Heidelberg, Clinical Radiology, Radiation Therapy, Heidelberg, Germany 2German Cancer Research Center, Radiation Therapy, Heidelberg, Germany 3University of Heidelberg, Pathology, Heidelberg, Germany Aim: The aim of this study was to investigate the effects of interstitial CLDR and PDR brachytherapy on ploidy and cell cycle distribution in a syngeneic rat prostate tumor model. Methods: Interstitial PDR and CLDR brachytherapy were administered to the Dunning prostate R3327-AT1 carcinoma transplanted subcutaneously into the right thigh of Copenhagen rats. A dose of 20 and 40 Gy was administered in each study arm (CLDR versus PDR). 3 animals were irradiated per dose group, exposure condition, and dose group. Interstitial PDR was carried out using a 37 GBq 1921r source with 0,75 Gy/pulse and hour. CLDR was administered with a centrally implanted seed with a dose rate of 0,75 Gy/h. The dose was prescribed to the tumor surface (5 mm source distance, tumor diameter 10 mm). Flow cytometric measurements (n=3-5) were performed 4, 24, 48, 72, 96, and 120 h after the initiation of brachytherapy. Results: The following median percentages of diploid and aneuploid (in brackets) tumor cell fractions at 4, 24, 48, 72, 96, and 120 h were measured:CLDR 20 Gy (%): 86 (14), 69 (29), 62 (38), 78 (22), 70 (27), 85 (2)PDR 20 Gy (%): 77 (19), 67 (26), 70 (22), 63 (39), 69 (31), 70 (10)CLDR 40 Gy (%): 90 (10), 65 (35), 79 (21), 79 (21), 75 (25), 85 (15)PDR 40 Gy (%): 79 (21), 76 (21), 80 (20), 76 (24), 92 (8), 95 (5). Additionally, the cell cycle distribution was compared in the different treatment and dose groups. Conclusion: As a first result of these flow cytometric measurements, CLDR and PDR brachytherapy showed no differential effects on cell cycle distribution and ploidy. 55
poster review
Precision and dose conformation in the CT-based reconstruction of interstitial brachytherapy F.W. Henslev I W. Harms 1, R. Krempien 1, P. Fritz2, M. Wannenmacher 1 1Un iversity Cfinics, Ruprecht Karl University Heide, Dept. of Radiotherapy, Heidelberg, Germany 2St. Marien-Krankenhaus , Dept.of Radiooncology, Siegen, Germany Puroose: CT-based reconstruction of brachytherapy implants and applicators introduces major improvements in conformal brachytherapy. However, the precision of CT reconstruction is restricted by a number of uncertainties. This includes patient movement during the longer duration of the scan session, but also mislocations produced by the finite thickness and distance of the CT slices. Further uncertainties are introduced by CT resolution, artifacts, image distortion, and also by imperfections in the computer-user interface. Aim of this work is to assess the geometrical uncertainties of CTbasesd reconstruction and their impact on target volume definition and the resulting distortion of the dose distribution. Materials and methods: Both radiograph and CT reconstructions were performed for a phantom and for a series of 33 patients with interstitial breast implants. CT studies were aquired for slice distances of 1.5, 2, 3, and 5ram. After transformation of both reconstructions to an identical coordinate system, the geometrical distances between corresponding dwell positions were determined. Histograms were calculated showing the distribution of shifts in three coordinates. The standard deviation of the histograms is taken as