- Email: [email protected]
Sleeved seeds decrease post-implant hotspots in real-time intraoperatively planned permanent 125I prostate implants
Oral Presentations / Brachytherapy 8 (2009) 105e180 after experiencing a bounce as opposed to 1 (3%) patient by the Phoenix (nadir +2 ng/mL) definition. Both definitions are prone to false positive calls during the bounce period. Conclusions: As noted by many investigators performing permanent seed brachytherapy, PSA bounce is a relatively common finding and this holds true for our population of patients treated with combination EBRT and HDR brachytherapy boost. In our study, age, pre-treatment PSA, prostate volume, Gleason score or any dosimetric parameter were not predictive of PSA bounce. Patients should be advised of the potential for a bounce in the PSA and the physicians involved in the care of these patients need to be well informed about this issue, thereby avoiding inappropriate initiation of salvage therapy.
PO106 Comparative study of permanent interstitial prostate brachytherapy post-implant evaluation among two North American institutes Felipe G. Balbontin, M.D. Urology , Clı´nica Santa Marı´a, Santiago, Chile. Purpose: The purposes of this study is the evaluation of two North American brachytherapy centers Seattle Prostate Institute (SPI) and British Columbia Cancer Center (BCCC) whether the dosimetric results are comparable, or when considering the inter-observer variability and the different scanning protocols used. This work is to be considered to test the value of two different center studies based on dosimetric evaluation of the quality of the implants and to analyze the differences when the CT scan was performed one day or one month after the implant. Methods and Materials: Between 2005 and 2008, 82 patients were implanted at Clı´nica Santa Marı´a, Santiago, Chile, all the preplans were made at BCCC. All the patients were implanted by one brachytherapist, only 125I monotherapy was used. The post plans were made at two different centers, with wide experience. VariSeedÔ (Varian Medical Systems, Inc., Palo Alto, CA) software was used in both centers. The CT scan was performed one day or one month after the implant, D90 and V150 were used to compare the results. Results: 70 (85%) CT scan of the 82 patients was done. Thirty three (47%) were scanned the day after and 28 (40%) were analyzed at SPI. Thirteen (46%) of the CT scan analyzed by SPI were donethe day after and 20 (48%) at BCCC were one month after the implant. D90 and V150 was a significantly different (p!0.05) if they were performed one day or one month after the implant. D90 average was 134 Gy (range 99-169) of the CT scan analyzed the day after the implant and D90 average was 154 Gy (range 103-229) one month after. V150 average was 41 Gy (range 22-63) and 56 Gy (range 68-72) one day and one month respectively. There was no significant difference between the two centers, neither D90 and V150, nor day one or one month after the implant. Conclusions: D90 is 13% and V150 is 27% lower if the CT scan were performed one day instead one month after the implant, most probably because of the edema causes by the needles. Although the post-plan depends on the operator that contours the prostate, no differences exist between two centers with wide experiences.
PO107 Sleeved seeds decrease post-implant hotspots in real-time intraoperatively planned permanent 125I prostate implants Randi J. Cohen, M.D., M.S1 Navesh K. Sharma, D.O., Ph.D.1 Jinsheng Li, Ph.D.1 Karen J. Ruth, M.S.2 Mark K. Buyyounouski, M.D., M.S.1 Kevin Crawford, B.S.1 Robert G. Uzzo, M.D.3 Eric M. Horwitz, M.D.1 1 Radiation Oncology Fox Chase Cancer Center, Philadelphia, PA; 2 Biostatistics, Fox Chase Cancer Center, Philadelphia, PA; 3Urologic Oncology, Fox Chase Cancer Center, Philadelphia, PA. Purpose: To compare the day 1 and week 3 post-implant dosimetry of loose versus sleeved seeds in prostate cancer patients treated definitively with a permanent 125I implant. Methods and Materials: Dosimetric analysis was performed on 120 consecutive low-risk prostate cancer patients treated with a permanent 125I prostate seed implant at Fox Chase Cancer Center between 2003 and 2007.
179
A real-time intra-operative treatment plan with customized needle positions and seed-spacer sequences was generated for each patient using the VariseedÒ planning system. A 3 to 5 mm lateral and anterior expansion was added to the intra-operative, ultrasound generated prostate volume; 145 Gy was prescribed to cover 100% of the prostate volume. Beginning late 2005, the seeds and spacers were encased in a PGA and Lactide (suture material) ‘‘sleeve’’ to reduce seed migration. Post-implant CT and MRI scans were obtained and post-implant dosimetry performed several hours after the implant (day 1) and approximately 21 days following the implant (week 3). Sixty patients with sleeved seeds were compared to the most recent 60 patients treated with loose seeds in regards to real-time treatment volume, activity of the implant, number of seeds and needles, and realtime, day 1, and day 21 dosimetry using a two-tailed, unpaired, t-test. Dosimetric parameters of interest included the V150, V100, D90, and D50. The D1 was also compared as a measure of ‘‘hotspots.’’ Results: The planned treatment volume was smaller for the sleeved versus loose seeds (44.3 cc vs. 49.0 cc, p 5 0.02). There was no difference in mean activity per seed in the two groups (0.388 mCi sleeved vs. 0.380 mCi loose, p 5 0.31), although the total activity was slightly lower for patients with sleeved seeds (30.9 mCi vs. 32.9 mCi, p 5 0.06) due to fewer seeds implanted (79 vs. 87, p 5 0.0003). Fewer needles, on average, were used in patients treated with sleeved seeds (17 vs. 21, p!0.0001). There was no difference in the real-time V150 (61.8% vs. 63.0%), V100 (98.2% vs. 98.2%), D90 (176.0 Gy vs. 176.0 Gy), or D50 (234.5 Gy vs. 235.4 Gy) for sleeved versus loose seeds, respectively. The real-time planning D1, however, was significantly greater for the sleeved seeds (1577.2 Gy vs. 1121.1 Gy, p 5 0.0003). Day 1 dosimetry was significant for a lower D90 (120.6 Gy vs. 129.3 Gy, p 5 0.02) in sleeved patients. There was no difference in the day 1 V150 (42.0% vs. 39.3%), V100 (80.9% vs. 83.3%), D50 (198.7 Gy vs. 197.9 Gy), and D1 (841.0 Gy vs. 860.6 Gy) between patients with sleeved and loose seeds. Week 3 analysis demonstrated a significantly lower D1 (931.5 Gy vs. 995.5 Gy, p 5 0.01) in sleeved patients, but no difference in V150 (56.7% vs. 55.5%), V100 (88.2% vs. 88.2%), D90 (140.8 Gy vs. 140.4 Gy), or D50 (228.3 Gy vs. 228.9 Gy). Conclusions: Post-implant dosimetry of patients with sleeved seeds demonstrated a lower day 1 D90 and week 3 D1. As the prostate swells secondary to the trauma of an implant, separation of the isodose lines becomes more prominent in those patients with fewer sources, as is the case for patients with sleeved seeds. As swelling resolves three weeks later, the difference in the D90 between the two groups also resolves. The lower week 3 D1 may be related to reduced seed migration. Despite fewer seeds and needles in sleeved patients, the real-time planning D1 was greater in that population. The D1 can be used as a surrogate for hotspots within the prostate, which may result in patient toxicity, especially if located near the rectum or urethra. PO108 Sleeved seeds decrease gastrointestinal and genitourinary toxicity profiles in real-time intraoperatively planned permanent 125I implants Navesh K. Sharma, D.O., Ph.D.1 Randi J. Cohen, M.D., M.S.1 Karen Ruth, M.S.2 Kevin Crawford, B.S.1 Jinsheng Li, Ph.D.1 Mark K. Buyyounouski, M.D., M.S.1 Robert Uzzo, M.D.3 Steven J. Feigenberg, M.D.1 Eric M. Horwitz, M.D.1 1Radiation Oncology Fox Chase Cancer Center, Philadelphia, PA; 2Biostatistics, Fox Chase Cancer Center, Philadelphia, PA; 3Urologic Oncology, Fox Chase Cancer Center, Philadelphia, PA. Purpose: Current attempts in low-dose-rate (LDR) brachytherapy are aimed at reducing doses to organs at risk while maintaining adequate prostatic doses. We have developed a novel technique for real-time intraoperatively planned LDR prostate brachytherapy that attempts to overcome drawbacks of loose seeding by utilizing recent software advances and an innovative method of loading seed-spacer sequences in an absorbable tissue suture material. This study compares acute and late gastrointestinal (GI) and genitourinary (GU) toxicity profiles associated with loose versus sleeved seeds. Methods and Materials: Records of all men treated with permanent 125I LDR brachytherapy implants at Fox Chase Cancer Center (FCCC) from
PO106 Comparative study of permanent interstitial prostate brachytherapy post-implant evaluation among two North American institutes Felipe G. Balbontin, M.D. Urology , Clı´nica Santa Marı´a, Santiago, Chile. Purpose: The purposes of this study is the evaluation of two North American brachytherapy centers Seattle Prostate Institute (SPI) and British Columbia Cancer Center (BCCC) whether the dosimetric results are comparable, or when considering the inter-observer variability and the different scanning protocols used. This work is to be considered to test the value of two different center studies based on dosimetric evaluation of the quality of the implants and to analyze the differences when the CT scan was performed one day or one month after the implant. Methods and Materials: Between 2005 and 2008, 82 patients were implanted at Clı´nica Santa Marı´a, Santiago, Chile, all the preplans were made at BCCC. All the patients were implanted by one brachytherapist, only 125I monotherapy was used. The post plans were made at two different centers, with wide experience. VariSeedÔ (Varian Medical Systems, Inc., Palo Alto, CA) software was used in both centers. The CT scan was performed one day or one month after the implant, D90 and V150 were used to compare the results. Results: 70 (85%) CT scan of the 82 patients was done. Thirty three (47%) were scanned the day after and 28 (40%) were analyzed at SPI. Thirteen (46%) of the CT scan analyzed by SPI were donethe day after and 20 (48%) at BCCC were one month after the implant. D90 and V150 was a significantly different (p!0.05) if they were performed one day or one month after the implant. D90 average was 134 Gy (range 99-169) of the CT scan analyzed the day after the implant and D90 average was 154 Gy (range 103-229) one month after. V150 average was 41 Gy (range 22-63) and 56 Gy (range 68-72) one day and one month respectively. There was no significant difference between the two centers, neither D90 and V150, nor day one or one month after the implant. Conclusions: D90 is 13% and V150 is 27% lower if the CT scan were performed one day instead one month after the implant, most probably because of the edema causes by the needles. Although the post-plan depends on the operator that contours the prostate, no differences exist between two centers with wide experiences.
PO107 Sleeved seeds decrease post-implant hotspots in real-time intraoperatively planned permanent 125I prostate implants Randi J. Cohen, M.D., M.S1 Navesh K. Sharma, D.O., Ph.D.1 Jinsheng Li, Ph.D.1 Karen J. Ruth, M.S.2 Mark K. Buyyounouski, M.D., M.S.1 Kevin Crawford, B.S.1 Robert G. Uzzo, M.D.3 Eric M. Horwitz, M.D.1 1 Radiation Oncology Fox Chase Cancer Center, Philadelphia, PA; 2 Biostatistics, Fox Chase Cancer Center, Philadelphia, PA; 3Urologic Oncology, Fox Chase Cancer Center, Philadelphia, PA. Purpose: To compare the day 1 and week 3 post-implant dosimetry of loose versus sleeved seeds in prostate cancer patients treated definitively with a permanent 125I implant. Methods and Materials: Dosimetric analysis was performed on 120 consecutive low-risk prostate cancer patients treated with a permanent 125I prostate seed implant at Fox Chase Cancer Center between 2003 and 2007.
179
A real-time intra-operative treatment plan with customized needle positions and seed-spacer sequences was generated for each patient using the VariseedÒ planning system. A 3 to 5 mm lateral and anterior expansion was added to the intra-operative, ultrasound generated prostate volume; 145 Gy was prescribed to cover 100% of the prostate volume. Beginning late 2005, the seeds and spacers were encased in a PGA and Lactide (suture material) ‘‘sleeve’’ to reduce seed migration. Post-implant CT and MRI scans were obtained and post-implant dosimetry performed several hours after the implant (day 1) and approximately 21 days following the implant (week 3). Sixty patients with sleeved seeds were compared to the most recent 60 patients treated with loose seeds in regards to real-time treatment volume, activity of the implant, number of seeds and needles, and realtime, day 1, and day 21 dosimetry using a two-tailed, unpaired, t-test. Dosimetric parameters of interest included the V150, V100, D90, and D50. The D1 was also compared as a measure of ‘‘hotspots.’’ Results: The planned treatment volume was smaller for the sleeved versus loose seeds (44.3 cc vs. 49.0 cc, p 5 0.02). There was no difference in mean activity per seed in the two groups (0.388 mCi sleeved vs. 0.380 mCi loose, p 5 0.31), although the total activity was slightly lower for patients with sleeved seeds (30.9 mCi vs. 32.9 mCi, p 5 0.06) due to fewer seeds implanted (79 vs. 87, p 5 0.0003). Fewer needles, on average, were used in patients treated with sleeved seeds (17 vs. 21, p!0.0001). There was no difference in the real-time V150 (61.8% vs. 63.0%), V100 (98.2% vs. 98.2%), D90 (176.0 Gy vs. 176.0 Gy), or D50 (234.5 Gy vs. 235.4 Gy) for sleeved versus loose seeds, respectively. The real-time planning D1, however, was significantly greater for the sleeved seeds (1577.2 Gy vs. 1121.1 Gy, p 5 0.0003). Day 1 dosimetry was significant for a lower D90 (120.6 Gy vs. 129.3 Gy, p 5 0.02) in sleeved patients. There was no difference in the day 1 V150 (42.0% vs. 39.3%), V100 (80.9% vs. 83.3%), D50 (198.7 Gy vs. 197.9 Gy), and D1 (841.0 Gy vs. 860.6 Gy) between patients with sleeved and loose seeds. Week 3 analysis demonstrated a significantly lower D1 (931.5 Gy vs. 995.5 Gy, p 5 0.01) in sleeved patients, but no difference in V150 (56.7% vs. 55.5%), V100 (88.2% vs. 88.2%), D90 (140.8 Gy vs. 140.4 Gy), or D50 (228.3 Gy vs. 228.9 Gy). Conclusions: Post-implant dosimetry of patients with sleeved seeds demonstrated a lower day 1 D90 and week 3 D1. As the prostate swells secondary to the trauma of an implant, separation of the isodose lines becomes more prominent in those patients with fewer sources, as is the case for patients with sleeved seeds. As swelling resolves three weeks later, the difference in the D90 between the two groups also resolves. The lower week 3 D1 may be related to reduced seed migration. Despite fewer seeds and needles in sleeved patients, the real-time planning D1 was greater in that population. The D1 can be used as a surrogate for hotspots within the prostate, which may result in patient toxicity, especially if located near the rectum or urethra. PO108 Sleeved seeds decrease gastrointestinal and genitourinary toxicity profiles in real-time intraoperatively planned permanent 125I implants Navesh K. Sharma, D.O., Ph.D.1 Randi J. Cohen, M.D., M.S.1 Karen Ruth, M.S.2 Kevin Crawford, B.S.1 Jinsheng Li, Ph.D.1 Mark K. Buyyounouski, M.D., M.S.1 Robert Uzzo, M.D.3 Steven J. Feigenberg, M.D.1 Eric M. Horwitz, M.D.1 1Radiation Oncology Fox Chase Cancer Center, Philadelphia, PA; 2Biostatistics, Fox Chase Cancer Center, Philadelphia, PA; 3Urologic Oncology, Fox Chase Cancer Center, Philadelphia, PA. Purpose: Current attempts in low-dose-rate (LDR) brachytherapy are aimed at reducing doses to organs at risk while maintaining adequate prostatic doses. We have developed a novel technique for real-time intraoperatively planned LDR prostate brachytherapy that attempts to overcome drawbacks of loose seeding by utilizing recent software advances and an innovative method of loading seed-spacer sequences in an absorbable tissue suture material. This study compares acute and late gastrointestinal (GI) and genitourinary (GU) toxicity profiles associated with loose versus sleeved seeds. Methods and Materials: Records of all men treated with permanent 125I LDR brachytherapy implants at Fox Chase Cancer Center (FCCC) from