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Long-term disease control and patterns of failure in early stage testicular seminoma treated with limited or extended-field radiotherapy portals
Proceedings of the 46th Annual ASTRO Meeting
median V10 was 93.4%, V20 was 76.1%, V30 was 66.3%, V40 was 60.4%, V50 was 55.7%, V60 was 49.2%, V70 was 43.7%, V80 was 37.5%, V90 was 29.2%, and V100 was 17.8%. None of the dosimetric variables examined (total dose, penile bulb mean dose, D50, V10, V20, V30, V40, V50, V60, V70, V80, V90, and V100) predicted for ED after IMRT. Conclusions: IMRT is being used increasingly to escalate the dose to the target and reduce the dose to the surrounding normal tissues in prostate cancer. To date, this is the first analysis of sexual QOL in patients treated with IMRT for prostate cancer. The preservation of sexual function is not compromised when higher doses are delivered with IMRT, validating the ability of IMRT to limit erectile tissue dose. Sildenafil significantly improved sexual function for those with ED, even after long time intervals from IMRT.
1024
Surveillance is a Safe Alternative to Up-Front Post-Operative Adjuvant Therapy for Stage I Testicular Seminoma After Radical Inguinal Orchiectomy
G. Thomas, R. Choo, T. Woo, B. Kong, D. Lee, C. Danjoux, G. Morton Department of Radiation Oncology, Toronto Sunnybrook Regional Cancer Centre, Toronto, ON, Canada Purpose/Objective: Management options for stage I seminoma of the testis after radical inguinal orchiectomy (RIO) are diverse and range from post-operative adjuvant radiotherapy (RT) to surveillance alone with the reservation of RT or chemotherapy for the salvage of relapse. Surveillance strategy has been feasible because of better understanding of relapse pattern, the application of high-quality imaging tools for early detection of relapse, and the availability of highly effective salvage treatment for relapse. The aim of this report is to examine a long-term outcome and patterns of relapse in stage I testicular seminoma managed with surveillance alone after RIO. Materials/Methods: A prospective, single arm, study was conducted to evaluate surveillance strategy for stage I testicular seminoma. Patients must have met the following eligibility criteria: 1. Histologic diagnosis of seminoma, 2. RIO, 3. No evidence of nodal or distant metastasis, 4. Absence of tumor in the cut end of the spermatic cord, 5 Normal post-operative serum alpha-fetoprotein (AFP) and beta-human chorionic gonadotropin (bHCG), 6. Informed consent. Patients received no postoperative adjuvant therapy. Instead, they were followed closely in accordance to regular, pre-defined, schedules. Surveillance evaluations included: 1. Physical examination, AFP, bHCG, and Chest x-ray: q2months for year 1–2, q6months for year 3–5, and yearly thereafter, 2. CT scan of abdomen and pelvis: q4months for year 1–2, q6months for year 3–5, and yearly thereafter. Results: The study accrued a total of 88 patients with stage I testicular seminoma between 1986 and 1996. Median age at the time of RIO was 34 years (range: 20 – 66). The most common presenting complaint was a painless testicular mass. Six patients gave a history of cryptorchidism and four of them underwent orchiopexy. None had trans-scrotal biopsy prior to RIO. Median follow-up as of June 2003 was 12.1 years (range: 1–18.3). In 3 patients, follow-up was less than 2 years, as they failed to return to the clinic for surveillance. 71 remained free of relapse, while 17 relapsed. Actuarial relapse-free rates were 83%, 80%, and 80% at 5, 10, and 15 years, respectively. Median time to relapse was 13.6 months (range: 6.9 – 86.5). Only 2 had a late relapse beyond 5 years after RIO. Relapse sites of the 17 patients were: 12: paraaortic (PA) nodes only, 1: PA and external iliac nodes, 2: inguinal nodes, 1: PA and mediastinal nodes, 1: mediastinum and lung. Relapse was first detected by radiological investigations in 15 cases, and by clinical assessment in 2. The 2 cases detected clinically were those with isolated inguinal node relapse. 3 out of 6 patients with a history of cryptorchid and/or orchiopexy had relapse (2 in the ipsilateral inguinal nodes and 1 in the PA nodes). None had elevated bHCG or AFT at the time of recurrence. Of the 17 relapsed, 14 were treated with RT and 3 with chemotherapy (bleomycin, VP-16, cisplatin). Only 1 had a second relapse. This patient, initially treated with RT for the first relapse, was further salvaged by chemotherapy. All 17 relapsed patients have remained free of recurrence after salvage treatment with median follow-up of 10.5 years (range: 6.2–15.3). None died of seminoma. There were 2 deaths in the cohort: one due to myocardial infarct and the other due to cerebrovascular accident. Factors assessed for predictive factor for relapse were age, elapsed time from the detection of testicular mass to RIO, tumor size, invasion into the rete testis, invasion into the tunica, vascular/lymphatic invasion, and the presence of syncytiotrophoblast element. The only significant predictive factor for relapse on Cox proportional hazards model was the presence/absence of rete testis invasion (hazard ratio⫽3.5, p ⫽ 0.026). Conclusions: Surveillance with reservation of RT or chemotherapy for salvage of relapse is a safe alternative to upfront postoperative adjuvant therapy for stage I testicular seminoma.
1025
Long-Term Disease Control and Patterns of Failure in Early Stage Testicular Seminoma Treated with Limited or Extended-Field Radiotherapy Portals
M. Spierer,1 K. Alektiar,1 G. Bosl,2 J. Sheinfeld,3 M. Zelefsky1 Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY, 2Medicine, Memorial Sloan-Kettering Cancer Center, New York, NY, 3Urology, Memorial Sloan-Kettering Cancer Center, New York, NY 1
Purpose/Objective: To report tumor control outcomes and patterns of failure in patients who received radiotherapy limited to the para-aortic region (PA) or PA plus ipsilateral iliac lymph node (dogleg, DL) radiation therapy for early stage testicular seminoma, and to analyze outcomes among stage I patients with known negative histopathologic characteristics. Materials/Methods: From 1990 –2002, 198 patients were treated with radiation therapy (RT) for stages I and II seminoma. One hundred forty-five patients (73%) were stage I and 53 (27%) patients had stage II disease. Of the patients with stage I disease, 52 (36%) were treated with PA RT and 93 (64%) were treated with DL RT. A retrospective review of pathology reports was conducted to identify prognostic factors that have been associated with relapse in patients who are observed after orchiectomy (primary tumor size ⬎ 4cm and rete testis involvement). Sufficient pathologic data were available for 126 stage I patients (47/52 PA patients and 77/93 DL patients). Of these, 63% of patients treated with PA RT and 61% stage I patients treated with DL RT had one or both prognostic factors. Results: With a median follow-up time of 37 months (range: 1–161 months) after completion of RT, the 5-year actuarial local control (LC), distant metastasis-free survival (DMFS), and overall survival (OS) for stage I patients were 98%, 99% and 98% respectively and for stage II patients were 98%, 82%, and 97% respectively (p ⫽ NS for LC; p ⫽ .002 for DMFS; p ⫽ NS for
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OS). Four of 198 patients (2%) experienced local failure. Two of these patients underwent PA RT and relapsed in the external iliac lymph nodes. The other two failures underwent DL RT; one was stage I and one was stage II. One patient failed in his mid-abdomen within the radiation portal and one recurred at the margin of the radiation portal at the level of L2-L3. The one recurrent stage II patient subsequently developed distant metastasis. All four patients were treated with 4 cycles of etoposide and cisplatin chemotherapy. At the time of last follow-up, all four patients were without evidence of disease. The 5-year actuarial LC, DMFS, and OS for stage I patients treated with PA RT were 96%, 98%, and 100% respectively and for DL RT were 99%, 100%, and 98% respectively (p ⫽ NS). The presence of poor prognostic factors did not negatively impact LC, DMFS or OS. Conclusions: Excellent outcomes are observed for stage I and II seminoma treated with adjuvant RT. Omission of the pelvic field in stage I patients did not significantly impact upon LC, DMFS, or OS outcomes. Only 2% of patients treated with PA RT failed in the pelvic lymph nodes consistent with the results of the previously reported randomized trial. Stage I patients with negative histopathologic characteristics who are treated with RT have similar outcomes as those without these poor prognostic factors.
1026
Thirty Month Results with the MammoSite Breast Brachytherapy Applicator: Cosmesis, Toxicity and Local Control In Partial Breast Irradiation
M. Keisch,1 F. Vicini,2 T. Scroggins,3 M. Hebert,4 J. White,5 C. Quiet,6 R. Kuske,6 D. Arthur,7 O. Streeter8 Radiation Oncology, Mount Sinai Medical Center, Miami Beach, FL, 2William Beaumont Hospital, Royal Oak, MI, 3 Ochsner Clinic, New Orleans, LA, 4US Oncology, Sherman, TX, 5Medical College of Wisconsin, Milwaukee, WI, 6Arizona Oncology, Phoenix, AZ, 7Virginia Commonwealth University, Richmond, VA, 8USC Norris Cancer Center, Los Angeles, CA 1
Purpose/Objective: We update the initial cohort of MammoSite balloon breast brachytherapy patients by presenting the 30 month cosmetic outcome, toxicity, and local control in patients receiving accelerated partial breast irradiation. Materials/Methods: Forty-three patients enrolled and treated in a multi-center prospective trial from May 2000 to October 2001 testing the device for safety and performance for FDA approval constitute the study population. A dose of 34 Gy was delivered in 10 fractions over 5 days prescribed to 1 cm from the applicator surface using iridium ⫺192 high dose rate brachytherapy. Cosmesis was prospectively assessed by investigators using Harvard criteria. Toxicity was assessed using the FDA COSTART Terminology. Results: With a median and mean follow-up of 29 months and 27 months respectively (range 1 to 41), 84% of patients (36/43) were reported to have a good/excellent cosmetic result. Of the 32 patients followed ⬎ 2 years, 78% had good/excellent results. Of the 20 patients followed ⬎ 2.5 years, 75% had good/excellent cosmetic results. Of the 8 patients followed ⬎ 3 year, 75% have experienced good/excellent cosmetic results. An analysis was performed of factors associated with a good/excellent cosmetic result. Variables examined included skin spacing (cutoffs of 6, 7, and 8 mm), median skin spacing by cosmesis, implant timing (closed cavity versus open cavity), balloon inflation volumes, the use of systemic chemotherapy, and patient age. Median skin spacing was significantly different in the excellent, good, and fair cosmetic groups (p ⫽ 0.004). Skin spacing is associated with a statistically significant improved cosmetic result at cutoffs of 6, 7, and 8 mm in separate 2 by 2 analyses (p ⫽ .015 , p ⫽ .019 , and p ⫽ .04 respectively). Linear regression analysis was performed and shows a continuous improvement in cosmesis with increasing skin spacing (p ⫽ .03). Cosmesis over time for patients with ⬎ 6mm of skin spacing were examined. In patients with follow-up greater than 1 year and skin spacing greater than 6 mm, cosmetic results in patients were excellent/good in 90% (n ⫽ 29). In patients with follow-up greater than 2 years and skin spacing greater than 6 mm, cosmetic results in patients were excellent/good in 91% (n ⫽ 22). In patients with follow-up greater than 3 years and skin spacing greater than 6 mm, cosmetic results were excellent/good in 100% (n ⫽ 7) Changes in cosmesis over time were examined in more detail. In the entire group forty-four percent of patients had no change in status from first to last observation (19/43). Patients with changes in cosmesis over time both worsened (35%), and improved (21%). Changes in cosmesis over time for the group with skin spacing greater than 6 mm were also examined . From one year onward, only 3/29 (10%) changed status downward from good to fair cosmesis, and 2/29 (7%) of patients improved from fair to good cosmesis. From one year onward, only 6/29 (21%) changed status downward from excellent to good cosmesis and 10/29 (34%)of patients improved from good to excellent cosmesis. Two patients experienced fat necrosis (4.9%). None were symptomatic or required treatment. No patient has developed adverse sequelae requiring surgical correction or chronic analgesics. 11 patients (27%) had local telangectasias and 12 patients had localized fibrosis (29%). Patient satisfaction was rated excellent or good 98% of the time. No local failures have occurred. Conclusions: 30 month overall cosmetic outcome with the MammoSite balloon breast brachytherapy applicator was good-toexcellent in 84% of patients. Skin spacing correlates strongly with cosmesis. Patients with at least 7 mm of skin spacing appear to have stable cosmesis out to 3 years. Toxicity at this evaluation remains minimal. Patient acceptance is excellent. No ipsilateral breast failures have occurred.
1027
Dose Overestimation in Balloon Catheter Brachytherapy for Breast Cancer
S. Ye, R. Ove, S. Shen, S. Russo, I. A. Brezovich Radiation Oncology, Univ of Alabama School of Medicine, Birmingham, AL Purpose/Objective: Balloon catheter brachytherapy is becoming widely used in the treatment of early-stage breast cancer, due to its ease of use, short learning curve, and requirement of only one interstitial catheter through the breast. However, recent studies have shown that the dosimetry is not as simple as previously thought, due to iodine-containing radiographic contrast medium in the balloon, the lack of scatter medium, as well as source anisotropy. Materials/Methods: We performed Monte Carlo (MC) simulations for a balloon catheter device (MammoSite RTS) and two commercial HDR sources (MicroSelectron and Varisource). A balloon of 4.5 cm-diameter containing contrast medium of
median V10 was 93.4%, V20 was 76.1%, V30 was 66.3%, V40 was 60.4%, V50 was 55.7%, V60 was 49.2%, V70 was 43.7%, V80 was 37.5%, V90 was 29.2%, and V100 was 17.8%. None of the dosimetric variables examined (total dose, penile bulb mean dose, D50, V10, V20, V30, V40, V50, V60, V70, V80, V90, and V100) predicted for ED after IMRT. Conclusions: IMRT is being used increasingly to escalate the dose to the target and reduce the dose to the surrounding normal tissues in prostate cancer. To date, this is the first analysis of sexual QOL in patients treated with IMRT for prostate cancer. The preservation of sexual function is not compromised when higher doses are delivered with IMRT, validating the ability of IMRT to limit erectile tissue dose. Sildenafil significantly improved sexual function for those with ED, even after long time intervals from IMRT.
1024
Surveillance is a Safe Alternative to Up-Front Post-Operative Adjuvant Therapy for Stage I Testicular Seminoma After Radical Inguinal Orchiectomy
G. Thomas, R. Choo, T. Woo, B. Kong, D. Lee, C. Danjoux, G. Morton Department of Radiation Oncology, Toronto Sunnybrook Regional Cancer Centre, Toronto, ON, Canada Purpose/Objective: Management options for stage I seminoma of the testis after radical inguinal orchiectomy (RIO) are diverse and range from post-operative adjuvant radiotherapy (RT) to surveillance alone with the reservation of RT or chemotherapy for the salvage of relapse. Surveillance strategy has been feasible because of better understanding of relapse pattern, the application of high-quality imaging tools for early detection of relapse, and the availability of highly effective salvage treatment for relapse. The aim of this report is to examine a long-term outcome and patterns of relapse in stage I testicular seminoma managed with surveillance alone after RIO. Materials/Methods: A prospective, single arm, study was conducted to evaluate surveillance strategy for stage I testicular seminoma. Patients must have met the following eligibility criteria: 1. Histologic diagnosis of seminoma, 2. RIO, 3. No evidence of nodal or distant metastasis, 4. Absence of tumor in the cut end of the spermatic cord, 5 Normal post-operative serum alpha-fetoprotein (AFP) and beta-human chorionic gonadotropin (bHCG), 6. Informed consent. Patients received no postoperative adjuvant therapy. Instead, they were followed closely in accordance to regular, pre-defined, schedules. Surveillance evaluations included: 1. Physical examination, AFP, bHCG, and Chest x-ray: q2months for year 1–2, q6months for year 3–5, and yearly thereafter, 2. CT scan of abdomen and pelvis: q4months for year 1–2, q6months for year 3–5, and yearly thereafter. Results: The study accrued a total of 88 patients with stage I testicular seminoma between 1986 and 1996. Median age at the time of RIO was 34 years (range: 20 – 66). The most common presenting complaint was a painless testicular mass. Six patients gave a history of cryptorchidism and four of them underwent orchiopexy. None had trans-scrotal biopsy prior to RIO. Median follow-up as of June 2003 was 12.1 years (range: 1–18.3). In 3 patients, follow-up was less than 2 years, as they failed to return to the clinic for surveillance. 71 remained free of relapse, while 17 relapsed. Actuarial relapse-free rates were 83%, 80%, and 80% at 5, 10, and 15 years, respectively. Median time to relapse was 13.6 months (range: 6.9 – 86.5). Only 2 had a late relapse beyond 5 years after RIO. Relapse sites of the 17 patients were: 12: paraaortic (PA) nodes only, 1: PA and external iliac nodes, 2: inguinal nodes, 1: PA and mediastinal nodes, 1: mediastinum and lung. Relapse was first detected by radiological investigations in 15 cases, and by clinical assessment in 2. The 2 cases detected clinically were those with isolated inguinal node relapse. 3 out of 6 patients with a history of cryptorchid and/or orchiopexy had relapse (2 in the ipsilateral inguinal nodes and 1 in the PA nodes). None had elevated bHCG or AFT at the time of recurrence. Of the 17 relapsed, 14 were treated with RT and 3 with chemotherapy (bleomycin, VP-16, cisplatin). Only 1 had a second relapse. This patient, initially treated with RT for the first relapse, was further salvaged by chemotherapy. All 17 relapsed patients have remained free of recurrence after salvage treatment with median follow-up of 10.5 years (range: 6.2–15.3). None died of seminoma. There were 2 deaths in the cohort: one due to myocardial infarct and the other due to cerebrovascular accident. Factors assessed for predictive factor for relapse were age, elapsed time from the detection of testicular mass to RIO, tumor size, invasion into the rete testis, invasion into the tunica, vascular/lymphatic invasion, and the presence of syncytiotrophoblast element. The only significant predictive factor for relapse on Cox proportional hazards model was the presence/absence of rete testis invasion (hazard ratio⫽3.5, p ⫽ 0.026). Conclusions: Surveillance with reservation of RT or chemotherapy for salvage of relapse is a safe alternative to upfront postoperative adjuvant therapy for stage I testicular seminoma.
1025
Long-Term Disease Control and Patterns of Failure in Early Stage Testicular Seminoma Treated with Limited or Extended-Field Radiotherapy Portals
M. Spierer,1 K. Alektiar,1 G. Bosl,2 J. Sheinfeld,3 M. Zelefsky1 Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY, 2Medicine, Memorial Sloan-Kettering Cancer Center, New York, NY, 3Urology, Memorial Sloan-Kettering Cancer Center, New York, NY 1
Purpose/Objective: To report tumor control outcomes and patterns of failure in patients who received radiotherapy limited to the para-aortic region (PA) or PA plus ipsilateral iliac lymph node (dogleg, DL) radiation therapy for early stage testicular seminoma, and to analyze outcomes among stage I patients with known negative histopathologic characteristics. Materials/Methods: From 1990 –2002, 198 patients were treated with radiation therapy (RT) for stages I and II seminoma. One hundred forty-five patients (73%) were stage I and 53 (27%) patients had stage II disease. Of the patients with stage I disease, 52 (36%) were treated with PA RT and 93 (64%) were treated with DL RT. A retrospective review of pathology reports was conducted to identify prognostic factors that have been associated with relapse in patients who are observed after orchiectomy (primary tumor size ⬎ 4cm and rete testis involvement). Sufficient pathologic data were available for 126 stage I patients (47/52 PA patients and 77/93 DL patients). Of these, 63% of patients treated with PA RT and 61% stage I patients treated with DL RT had one or both prognostic factors. Results: With a median follow-up time of 37 months (range: 1–161 months) after completion of RT, the 5-year actuarial local control (LC), distant metastasis-free survival (DMFS), and overall survival (OS) for stage I patients were 98%, 99% and 98% respectively and for stage II patients were 98%, 82%, and 97% respectively (p ⫽ NS for LC; p ⫽ .002 for DMFS; p ⫽ NS for
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OS). Four of 198 patients (2%) experienced local failure. Two of these patients underwent PA RT and relapsed in the external iliac lymph nodes. The other two failures underwent DL RT; one was stage I and one was stage II. One patient failed in his mid-abdomen within the radiation portal and one recurred at the margin of the radiation portal at the level of L2-L3. The one recurrent stage II patient subsequently developed distant metastasis. All four patients were treated with 4 cycles of etoposide and cisplatin chemotherapy. At the time of last follow-up, all four patients were without evidence of disease. The 5-year actuarial LC, DMFS, and OS for stage I patients treated with PA RT were 96%, 98%, and 100% respectively and for DL RT were 99%, 100%, and 98% respectively (p ⫽ NS). The presence of poor prognostic factors did not negatively impact LC, DMFS or OS. Conclusions: Excellent outcomes are observed for stage I and II seminoma treated with adjuvant RT. Omission of the pelvic field in stage I patients did not significantly impact upon LC, DMFS, or OS outcomes. Only 2% of patients treated with PA RT failed in the pelvic lymph nodes consistent with the results of the previously reported randomized trial. Stage I patients with negative histopathologic characteristics who are treated with RT have similar outcomes as those without these poor prognostic factors.
1026
Thirty Month Results with the MammoSite Breast Brachytherapy Applicator: Cosmesis, Toxicity and Local Control In Partial Breast Irradiation
M. Keisch,1 F. Vicini,2 T. Scroggins,3 M. Hebert,4 J. White,5 C. Quiet,6 R. Kuske,6 D. Arthur,7 O. Streeter8 Radiation Oncology, Mount Sinai Medical Center, Miami Beach, FL, 2William Beaumont Hospital, Royal Oak, MI, 3 Ochsner Clinic, New Orleans, LA, 4US Oncology, Sherman, TX, 5Medical College of Wisconsin, Milwaukee, WI, 6Arizona Oncology, Phoenix, AZ, 7Virginia Commonwealth University, Richmond, VA, 8USC Norris Cancer Center, Los Angeles, CA 1
Purpose/Objective: We update the initial cohort of MammoSite balloon breast brachytherapy patients by presenting the 30 month cosmetic outcome, toxicity, and local control in patients receiving accelerated partial breast irradiation. Materials/Methods: Forty-three patients enrolled and treated in a multi-center prospective trial from May 2000 to October 2001 testing the device for safety and performance for FDA approval constitute the study population. A dose of 34 Gy was delivered in 10 fractions over 5 days prescribed to 1 cm from the applicator surface using iridium ⫺192 high dose rate brachytherapy. Cosmesis was prospectively assessed by investigators using Harvard criteria. Toxicity was assessed using the FDA COSTART Terminology. Results: With a median and mean follow-up of 29 months and 27 months respectively (range 1 to 41), 84% of patients (36/43) were reported to have a good/excellent cosmetic result. Of the 32 patients followed ⬎ 2 years, 78% had good/excellent results. Of the 20 patients followed ⬎ 2.5 years, 75% had good/excellent cosmetic results. Of the 8 patients followed ⬎ 3 year, 75% have experienced good/excellent cosmetic results. An analysis was performed of factors associated with a good/excellent cosmetic result. Variables examined included skin spacing (cutoffs of 6, 7, and 8 mm), median skin spacing by cosmesis, implant timing (closed cavity versus open cavity), balloon inflation volumes, the use of systemic chemotherapy, and patient age. Median skin spacing was significantly different in the excellent, good, and fair cosmetic groups (p ⫽ 0.004). Skin spacing is associated with a statistically significant improved cosmetic result at cutoffs of 6, 7, and 8 mm in separate 2 by 2 analyses (p ⫽ .015 , p ⫽ .019 , and p ⫽ .04 respectively). Linear regression analysis was performed and shows a continuous improvement in cosmesis with increasing skin spacing (p ⫽ .03). Cosmesis over time for patients with ⬎ 6mm of skin spacing were examined. In patients with follow-up greater than 1 year and skin spacing greater than 6 mm, cosmetic results in patients were excellent/good in 90% (n ⫽ 29). In patients with follow-up greater than 2 years and skin spacing greater than 6 mm, cosmetic results in patients were excellent/good in 91% (n ⫽ 22). In patients with follow-up greater than 3 years and skin spacing greater than 6 mm, cosmetic results were excellent/good in 100% (n ⫽ 7) Changes in cosmesis over time were examined in more detail. In the entire group forty-four percent of patients had no change in status from first to last observation (19/43). Patients with changes in cosmesis over time both worsened (35%), and improved (21%). Changes in cosmesis over time for the group with skin spacing greater than 6 mm were also examined . From one year onward, only 3/29 (10%) changed status downward from good to fair cosmesis, and 2/29 (7%) of patients improved from fair to good cosmesis. From one year onward, only 6/29 (21%) changed status downward from excellent to good cosmesis and 10/29 (34%)of patients improved from good to excellent cosmesis. Two patients experienced fat necrosis (4.9%). None were symptomatic or required treatment. No patient has developed adverse sequelae requiring surgical correction or chronic analgesics. 11 patients (27%) had local telangectasias and 12 patients had localized fibrosis (29%). Patient satisfaction was rated excellent or good 98% of the time. No local failures have occurred. Conclusions: 30 month overall cosmetic outcome with the MammoSite balloon breast brachytherapy applicator was good-toexcellent in 84% of patients. Skin spacing correlates strongly with cosmesis. Patients with at least 7 mm of skin spacing appear to have stable cosmesis out to 3 years. Toxicity at this evaluation remains minimal. Patient acceptance is excellent. No ipsilateral breast failures have occurred.
1027
Dose Overestimation in Balloon Catheter Brachytherapy for Breast Cancer
S. Ye, R. Ove, S. Shen, S. Russo, I. A. Brezovich Radiation Oncology, Univ of Alabama School of Medicine, Birmingham, AL Purpose/Objective: Balloon catheter brachytherapy is becoming widely used in the treatment of early-stage breast cancer, due to its ease of use, short learning curve, and requirement of only one interstitial catheter through the breast. However, recent studies have shown that the dosimetry is not as simple as previously thought, due to iodine-containing radiographic contrast medium in the balloon, the lack of scatter medium, as well as source anisotropy. Materials/Methods: We performed Monte Carlo (MC) simulations for a balloon catheter device (MammoSite RTS) and two commercial HDR sources (MicroSelectron and Varisource). A balloon of 4.5 cm-diameter containing contrast medium of