- Email: [email protected]
Study of Day 7 and Day 60 Post-Seed Dosimetry Parameters for 131Cs Prostate Implants
S94
Abstracts / Brachytherapy 9 (2010) S23eS102
the prostate volume covered by prescription yields a best of fit line equated as Total Activity 5 2.6435(Prostate Vol)0.6577 with R2 5 0.99. The 99% CI of total implanted activity (mCi) was plotted against the prostate volume covered by prescription; the equation of best of fit line is Total Activity 5 2.636(Prostate Vol)0.6705 with R2 5 0.95. A comparison of the required activity from the preplanned based nomogram with 99% CI ‘‘seed ordering’’ interactive plan nomogram (Figure) reveals that the preplanned nomogram overestimates the activity by 24.5% on average. Conclusions: Equations for interactive prostate brachytherapy specific nomograms have been calculated. The equations for the total activity of an implant predict seed usage with a new nomogram based on interactive planning at 99% CI that accommodates varying gland geometries while minimizing wasted seeds.
PO38 Prostate Brachytherapy Seed Embolization to the Lung Using Modern Stranded and Linked Sources Daniel Landis, M.D., Ph.D.1,2, Robert Takamiya, M.D.1,2, Stephen Eulau, M.D.1,2 1Seattle Prostate Institute, Seattle, WA; 2Radiation Oncology, Swedish Cancer Institute, Seattle, WA.
Median Gleason score was 7 (range: 4 to 10). Median PSA was 0.8 (0.40 to 1.6). Treatment volumes ranged from 31 cm3 to 46 cm3. Treatment volume included the prostatic fossa and seminal vesicle region in all cases. Radiation treatment planning was performed using CT scanning and the PlatoÔ treatment planning system (Nucletron B.V., Veenendaal, The Netherlands). Our protocol for HDR, has called for two HDR implants, spaced 4 weeks apart. The treatment volume received 1800 cGy in 3 fractions prescribed to the 100% isodose line, given over 24 hours. A 2nd implant was performed 4 weeks later, delivering a further 1800 cGy in 3 fractions, bringing the final dose to the treatment volumes to 3,600 cGy in 6 fractions. Urethral dose points (12-16) were followed, and limited to <105% of the prescription dose. Results: With a median followup of 30 months (range: 18 months to 48 months), PSA measured !0.1 in 80% (4/5) of patients. There were no complications. Conclusions: HDR implant for salvage treatment of biochemical recurrence after radical prostatectomy is technically feasible, and well tolerated. With median 30-month followup, PSA results appear comparable to XRT or IMRT. By omitting XRT or IMRT, bladder and rectal doses and consequent complications may be reduced.
PO40 Purpose: Prostate brachytherapy is a safe treatment option for men with early stage prostate cancer. One rare risk of this technique is seed embolization through the prostatic venous plexus to the lung. We investigated the incidence and potential toxicity of this event with modern stranded and linked brachytherapy sources. Materials and Methods: A retrospective review was conducted on four hundred sixty-nine consecutive patients treated at our main center from January 2008 to October 2009. 125I was utilized in 66%, 103Pd in 32%, and 131Cs in 2% of patients. For each case, chest x-rays were reviewed by staff physicians. All questionable cases were reviewed by a radiologist. 125 I seeds were manufactured within a vicryl stranded product. Palladium seeds were contained within a commercial product linked with plastic connectors. Results: Nine radioactive seed pulmonary emboli were found in nine patients. The rate of detected seed embolus to the lung was 1.9%. Rate of embolization for 125I strands was 2.2% (n 5 7) and for the 103Pd product 1.3% (n 5 2). This difference was not statistically significant. No patient reported any detectable adverse clinical effect from seed embolization. Conclusions: Seed embolization using stranded and linked seed products occurs in approximately 1.9% of patients and in this limited sample had no observable clinical effect. In an era of striving to decrease medical costs and procedures, eliminating the routine chest x-ray after prostate brachytherapy can be considered.
PO39 HDR Salvage Treatment of PSA Only Recurrent Prostate Cancer after Radical Prostatectomy: A Feasibility Study in 5 Patients Rufus J. Mark, M.D.1, Paul J. Anderson, M.D.1, Robin S. Akins, M.D.2, Murali Nair, Ph.D.1 1Radiation Oncology, Joe Arrington Cancer Center, Lubbock, TX; 2Radiation Oncology, Wilford Hall Medical Center, Lackland Airforce Base, TX. Purpose: Salvage treatment options of biochemical recurrence after radical prostatectomy, include external beam radiation therapy (XRT), intensity modulated radiation therapy (IMRT), and hormonal blockade (HB). XRT and IMRT protocols call for about a 7-week course and carry some risk to the bladder and rectum. Permanent seed implants are not feasible because of seed migration. High-dose-rate (HDR) interstitial implant is theoretically possible. We present our results in 5 patients treated with HDR implant for biochemical recurrence after radical prostatectomy. Materials and Methods: Between 2005 and 2009, 5 patients with biochemical recurrence after radical prostatectomy underwent transrectal ultrasound-guided interstitial HDR implant for salvage. There were no Gleason score or PSA exclusions. No patient received adjuvant HB.
Study of Day 7 and Day 60 Post-Seed Dosimetry Parameters for 131 Cs Prostate Implants Ravindra Yaparpalvi, M.S., William Bodner, M.D., Raquibul Hannan, M.D., Ph.D., Hsiang-Chi Kuo, M.S., Madhur Garg, M.D., Dennis Mah, Ph.D., Shalom Kalnicki, M.D., Chandan Guha, M.D., Ph.D. Radiation Oncology, Montefiore Medical Center and the Albert Einstein College of Medicine, Bronx, NY. Purpose: To analyze postimplant dosimetry parameters based on CTimages taken at day 7 and day 60 and compare with those of intraoperative dosimetry for prostate 131Cs implants. Materials and Methods: Fifteen patients were treated in our institution with 131Cs (half-life 5 9.7 days) brachytherapy followed by external beam irradiation for intermediate- to high-risk prostate cancers. Intraoperative transrectal ultrasound (TRUS) volume study and activity optimization were performed for all patients. No hormonal therapy was given. We used a conservative approach aiming for boost prescription doses of 70-80 Gy at the start of our 131Cs seed program. CT scans were scheduled at approximately the end of 131Cs first half-life 7-10 days (CT7) (median 7 days, range 6-15 days) and again at the end of 131Cs sixhalf- lives CT60 (median 57 days, range 40-85 days). In all these patients, seed implantation was performed prior to EBRT and therefore, a second set of EBRT CT simulation scans at 2 months post seed implantation, were available for additional post-seed dose-volume evaluations. Detailed dose-volume analysis was performed for both intraoperative ultrasound and post-seed CT-data based data sets. All contouring on images was performed by a single radiation oncologist. The following data were collected and compared: Vi200, Vi150, Vi100, Vi90, Vi80 (implant volumes receiving 200, 150, 100, 90 and 80% of prescription dose) for the implant and D90 for prostate (dose received by 90% volume of prostate). For rectum, the absolute volume (cc) receiving 100 and 110% prescription dose (Vr100, Vr110) were collected from DVH data. Results: Intraoperative TRUS-based mean prostate volume was 24.3 (5.4) cc and postimplant CT7 and CT60 based prostate volumes were 27.7 (3.8) cc and 25.8 (4.1) cc, respectively. Median implanted activity was 113 mCi (range 86-134.5). The mean planned intraoperative prostate D90 was 75.8 (6.3) Gy, while the achieved CT7 and CT60 based D90 were 65.3 (11.4) and 66.6 (9.1) Gy respectively (p 5 0.35). Prostate intraoperative Vi100 and CT7 prostate D90 correlated significantly (p 5 0.0004, r 5 0.8). The Vi parameters correlated significantly between intraoperative and post-seed CT values (p!0.0001; r 5 0.80). Rectal Vr100 correlated weakly with total implant activity and prostate TRUS volume (p 5 0.03, r 5 0.56). The mean volume of rectum that receives between 100 to 110% of reference dose (Vr100- Vr110) increased two-fold based between CT7 and CT60 evaluations (0.04 cc (0.06) Vs 0.08 (0.07) cc, respectively, p 5 0.06) compared to 0 cc for intraoperative plan.
Abstracts / Brachytherapy 9 (2010) S23eS102 Conclusions: Based on our experience, albeit limited data, it appears that for 131Cs implants intraoperative TRUS and post-seed CT plan parameters correlate significantly for implant volume parameters and weakly for prostate dose parameters. This could be the result of post-seed CT timing, edema effects and importantly due to prostate contouring uncertainty between TRUS and CT images. While there is no consensus yet on the optimal timing of post seed imaging for 131Cs implants, our study has also shown that there is a tendency for rectal dose increase with elapsed time. We strongly believe that post-seed imaging at the beginning and at the end of active dose delivery period may very well be necessary to get an accurate picture for short-lived 131Cs implants compared to one-time post-seed imaging widely practiced for 125I implants.
PO41 Body Fat Distribution, Waist Circumference and Body Mass Index in Permanent Seed Prostate Brachytherapy Daniel Taussky, M.D., Catherine Ji, Sebastien Clavel, M.D., David Donath, M.D. Radiation Oncology, Centre Hospitalier de l’Universite´ de Montre´al, Montreal, QC, Canada. Purpose: Recent studies have shown that obesity is associated with more aggressive prostate cancer variants and a higher prostate specific antigen (PSA) recurrence following prostatectomy. The aim of this study is to analyze the influence of body mass index (BMI) and the distribution of adipose tissue on clinical pretreatment variables and PSA evolution post 125 I prostate brachytherapy. Materials and Methods: We studied 59 men with low risk or ‘low tier’’ intermediate risk (maximum one intermediate risk feature) prostate cancer who had undergone 125I radioactive seed implantation as monotherapy. Inclusion criteria were an absence of hormonal therapy or external beam radiotherapy, a minimum of 8 months of followup and at least 3 followup PSA values. We calculated the BMI (kg/m2), waist circumference and the quotient between visceral and subcutaneous fat (VF/SF) measured on computed tomography at the iliac crest level. To analyze the influence of anthropometric measures on post-brachytherapy PSA evolution, we divided the patients into 2 groups: 1) rapid PSA descent post-brachytherapy to !0.5 ng/mL in the first 12 months following brachytherapy (n 5 28); 2) slow PSA descent postbrachytherapy to !0.50 ng/mL and a followup of >24 months (n 5 23) or a PSA bounce of >0.50 ng/mL (n 5 6). The influence of those anthropometric measures on pretreatment PSA, prostate volume and number of positive biopsies were calculated using Spearman correlation coefficient. Differences between the 3? post-brachytherapy outcome groups were analyzed using the Pearson chi-square and Fisher’s exact test. Relative risk estimate was calculated to measure of the strength of the association between the presence of a factor and the occurrence of an event. All tests were two-tailed. Results: There was an influence of the different anthropometric measures on pretreatment characteristics; there was a positive correlation between VF/SF and the PSA before treatment (r 5 0.282, p 5 0.029); and waist circumference with the number of positive biopsies (r 5 0.374, p 5 0.004). VS/SF, BMI and waist circumference were not different between both post-brachytherapy PSA-outcome groups (p>0.439). The following factors were associated with being in the slow descent group: younger patients (less than the median age of 65 years), p 5 0.003, relative risk (RR) 2.256 (95% confidence interval (CI), 1.249-4.073) and prostates smaller than the median 41 cc, p 5 0.034, RR 0.550 (95%CI, 0.3200.944). All patients with a waist circumference of O100 cm were in the rapid descent group. Among the patients with a VF/SF O0.9, 83% were in the slow descent group. Conclusions: In this small pilot study, waist circumference and VF/SF were weakly correlated to pretreatment characteristics. There seems to be a tendency that an increase in visceral fat and waist circumference has an influence on the type of PSA response. Larger studies are needed to determine if anthropomorphic measures have a direct influence on postbrachytherapy PSA response.
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PO42 Hormonal Blockade for Salvage Treatment of PSA-Only Recurrent Prostate Cancer after Interstitial High-Dose-Rate Brachytherapy for Early Stage Prostate Cancer: 5-Year Followup in 25 Patients Rufus J. Mark, M.D.1, Robin Akins, M.D.2, Paul J. Anderson, M.D.1, Murali Nair, Ph.D1. 1Radiation Oncology, Joe Arrington Cancer Center, Lubbock, TX; 2Radiation Oncology, Wilford Hall Medical Center, Lackland Airforce Base, TX. Purpose: Salvage treatment of biochemical recurrence after radiation implant is a subject of considerable controversy. Management options include PSA surveillance, radical prostatectomy, cryosurgery, External Radiation Therapy (XRT), Intensity Modulated Radiation Therapy (IMRT), and Hormonal Blockade (HB). Complication risks after radical prostatectomy, cryosurgery, XRT and IMRT salvage can be significant. We present our results in 25 patients treated with HB for biochemical recurrence after High-dose-rate (HDR) implant. Materials and Methods: Between 1997 and 2009, 301 patients with T1 and T2 localized prostate underwent TRUS guided interstitial implant, under spinal anesthetic or local anesthetic. There were no Gleason Score or PSA exclusions. No patient received XRT, IMRT, or initial HB. Median Gleason Score was 7 (range: 4 to 10). Median PSA was 9.3 (2.7 to 39.8). At last followup, 36 patients had developed PSA only relapse. After a discussion of management options, 25 patients elected salvage treatment with intermittent HB, starting with Casodex. All patients started Casodex 50 mg qd with PSA !10. Results: With a median followup of 66 months (range: 6 months to 132 months), the PSA control rate on Casodex was 84% (21/25). Four patients have become refractory to Casodex, and were switched to Lupron. Two of these patients remain controlled on Lupron. One patient has entered a clinical trial for chemotherapy. One patient has died from metastatic prostate cancer. One patient developed bone metastases, which have cleared on Lupron. Side effects have been acceptable. One patient sustained a myocardial infarction, and a 2nd suffered a fractured hip. Conclusions: With median 5-year followup, HB appears to be a reasonable salvage option for patients experiencing a PSA-only relapse after HDR implant.
PO43 Previous Transurethral Resection of the Prostate Is Not a Contraindication for Interstitial High-Dose-Rate Brachytherapy for Prostate Cancer Rufus J. Mark, M.D.1, Paul J. Anderson, M.D.1, Robin S. Akins, M.D.2, Murali Nair, Ph.D.1 1Radiation Oncology, Joe Arrington Cancer Center, Lubbock, TX; 2Radiation Oncology, Wilford Hall Medical Center, Lackland Airforce Base, TX. Purpose: Transrectal ultrasound (TRUS)-guided interstitial implant for prostate cancer using low-dose-rate (LDR) and high-dose-rate (HDR) technique has been reported with results comparing favorably to surgery and external beam radiation therapy (EBRT). Previous TURP has been considered a relative contraindication for LDR permanent seed implant because of higher rates of urinary incontinence. There are little data on previous TURP and subsequent incontinence after HDR implant. We report our urinary incontinence results with HDR with or without previous TURP. Materials and Methods: Between 1997 and 2009, 410 patients with T1 and T2 localized prostate underwent TRUS guided interstitial implant. There were no Gleason score or PSA exclusions. After discussion of treatment options, 109 patients elected HDR Implant þ IMRT and 301 patients underwent HDR monotherapy. No patient received hormonal blockade. Median Gleason score was 7 (range: 4 to 10). Median PSA was 9.8 (0.60 to 39.8). IMRT treatment volume included the prostate þ seminal vesicles þ 2 cm margin. Implant treatment volumes ranged from 32 cm3 to 196 cm3. In patients who received IMRT þ HDR, 4500 cGy in 25 fractions was given via IMRT and 1650 cGy to 2000 cGy in 3 fractions
Abstracts / Brachytherapy 9 (2010) S23eS102
the prostate volume covered by prescription yields a best of fit line equated as Total Activity 5 2.6435(Prostate Vol)0.6577 with R2 5 0.99. The 99% CI of total implanted activity (mCi) was plotted against the prostate volume covered by prescription; the equation of best of fit line is Total Activity 5 2.636(Prostate Vol)0.6705 with R2 5 0.95. A comparison of the required activity from the preplanned based nomogram with 99% CI ‘‘seed ordering’’ interactive plan nomogram (Figure) reveals that the preplanned nomogram overestimates the activity by 24.5% on average. Conclusions: Equations for interactive prostate brachytherapy specific nomograms have been calculated. The equations for the total activity of an implant predict seed usage with a new nomogram based on interactive planning at 99% CI that accommodates varying gland geometries while minimizing wasted seeds.
PO38 Prostate Brachytherapy Seed Embolization to the Lung Using Modern Stranded and Linked Sources Daniel Landis, M.D., Ph.D.1,2, Robert Takamiya, M.D.1,2, Stephen Eulau, M.D.1,2 1Seattle Prostate Institute, Seattle, WA; 2Radiation Oncology, Swedish Cancer Institute, Seattle, WA.
Median Gleason score was 7 (range: 4 to 10). Median PSA was 0.8 (0.40 to 1.6). Treatment volumes ranged from 31 cm3 to 46 cm3. Treatment volume included the prostatic fossa and seminal vesicle region in all cases. Radiation treatment planning was performed using CT scanning and the PlatoÔ treatment planning system (Nucletron B.V., Veenendaal, The Netherlands). Our protocol for HDR, has called for two HDR implants, spaced 4 weeks apart. The treatment volume received 1800 cGy in 3 fractions prescribed to the 100% isodose line, given over 24 hours. A 2nd implant was performed 4 weeks later, delivering a further 1800 cGy in 3 fractions, bringing the final dose to the treatment volumes to 3,600 cGy in 6 fractions. Urethral dose points (12-16) were followed, and limited to <105% of the prescription dose. Results: With a median followup of 30 months (range: 18 months to 48 months), PSA measured !0.1 in 80% (4/5) of patients. There were no complications. Conclusions: HDR implant for salvage treatment of biochemical recurrence after radical prostatectomy is technically feasible, and well tolerated. With median 30-month followup, PSA results appear comparable to XRT or IMRT. By omitting XRT or IMRT, bladder and rectal doses and consequent complications may be reduced.
PO40 Purpose: Prostate brachytherapy is a safe treatment option for men with early stage prostate cancer. One rare risk of this technique is seed embolization through the prostatic venous plexus to the lung. We investigated the incidence and potential toxicity of this event with modern stranded and linked brachytherapy sources. Materials and Methods: A retrospective review was conducted on four hundred sixty-nine consecutive patients treated at our main center from January 2008 to October 2009. 125I was utilized in 66%, 103Pd in 32%, and 131Cs in 2% of patients. For each case, chest x-rays were reviewed by staff physicians. All questionable cases were reviewed by a radiologist. 125 I seeds were manufactured within a vicryl stranded product. Palladium seeds were contained within a commercial product linked with plastic connectors. Results: Nine radioactive seed pulmonary emboli were found in nine patients. The rate of detected seed embolus to the lung was 1.9%. Rate of embolization for 125I strands was 2.2% (n 5 7) and for the 103Pd product 1.3% (n 5 2). This difference was not statistically significant. No patient reported any detectable adverse clinical effect from seed embolization. Conclusions: Seed embolization using stranded and linked seed products occurs in approximately 1.9% of patients and in this limited sample had no observable clinical effect. In an era of striving to decrease medical costs and procedures, eliminating the routine chest x-ray after prostate brachytherapy can be considered.
PO39 HDR Salvage Treatment of PSA Only Recurrent Prostate Cancer after Radical Prostatectomy: A Feasibility Study in 5 Patients Rufus J. Mark, M.D.1, Paul J. Anderson, M.D.1, Robin S. Akins, M.D.2, Murali Nair, Ph.D.1 1Radiation Oncology, Joe Arrington Cancer Center, Lubbock, TX; 2Radiation Oncology, Wilford Hall Medical Center, Lackland Airforce Base, TX. Purpose: Salvage treatment options of biochemical recurrence after radical prostatectomy, include external beam radiation therapy (XRT), intensity modulated radiation therapy (IMRT), and hormonal blockade (HB). XRT and IMRT protocols call for about a 7-week course and carry some risk to the bladder and rectum. Permanent seed implants are not feasible because of seed migration. High-dose-rate (HDR) interstitial implant is theoretically possible. We present our results in 5 patients treated with HDR implant for biochemical recurrence after radical prostatectomy. Materials and Methods: Between 2005 and 2009, 5 patients with biochemical recurrence after radical prostatectomy underwent transrectal ultrasound-guided interstitial HDR implant for salvage. There were no Gleason score or PSA exclusions. No patient received adjuvant HB.
Study of Day 7 and Day 60 Post-Seed Dosimetry Parameters for 131 Cs Prostate Implants Ravindra Yaparpalvi, M.S., William Bodner, M.D., Raquibul Hannan, M.D., Ph.D., Hsiang-Chi Kuo, M.S., Madhur Garg, M.D., Dennis Mah, Ph.D., Shalom Kalnicki, M.D., Chandan Guha, M.D., Ph.D. Radiation Oncology, Montefiore Medical Center and the Albert Einstein College of Medicine, Bronx, NY. Purpose: To analyze postimplant dosimetry parameters based on CTimages taken at day 7 and day 60 and compare with those of intraoperative dosimetry for prostate 131Cs implants. Materials and Methods: Fifteen patients were treated in our institution with 131Cs (half-life 5 9.7 days) brachytherapy followed by external beam irradiation for intermediate- to high-risk prostate cancers. Intraoperative transrectal ultrasound (TRUS) volume study and activity optimization were performed for all patients. No hormonal therapy was given. We used a conservative approach aiming for boost prescription doses of 70-80 Gy at the start of our 131Cs seed program. CT scans were scheduled at approximately the end of 131Cs first half-life 7-10 days (CT7) (median 7 days, range 6-15 days) and again at the end of 131Cs sixhalf- lives CT60 (median 57 days, range 40-85 days). In all these patients, seed implantation was performed prior to EBRT and therefore, a second set of EBRT CT simulation scans at 2 months post seed implantation, were available for additional post-seed dose-volume evaluations. Detailed dose-volume analysis was performed for both intraoperative ultrasound and post-seed CT-data based data sets. All contouring on images was performed by a single radiation oncologist. The following data were collected and compared: Vi200, Vi150, Vi100, Vi90, Vi80 (implant volumes receiving 200, 150, 100, 90 and 80% of prescription dose) for the implant and D90 for prostate (dose received by 90% volume of prostate). For rectum, the absolute volume (cc) receiving 100 and 110% prescription dose (Vr100, Vr110) were collected from DVH data. Results: Intraoperative TRUS-based mean prostate volume was 24.3 (5.4) cc and postimplant CT7 and CT60 based prostate volumes were 27.7 (3.8) cc and 25.8 (4.1) cc, respectively. Median implanted activity was 113 mCi (range 86-134.5). The mean planned intraoperative prostate D90 was 75.8 (6.3) Gy, while the achieved CT7 and CT60 based D90 were 65.3 (11.4) and 66.6 (9.1) Gy respectively (p 5 0.35). Prostate intraoperative Vi100 and CT7 prostate D90 correlated significantly (p 5 0.0004, r 5 0.8). The Vi parameters correlated significantly between intraoperative and post-seed CT values (p!0.0001; r 5 0.80). Rectal Vr100 correlated weakly with total implant activity and prostate TRUS volume (p 5 0.03, r 5 0.56). The mean volume of rectum that receives between 100 to 110% of reference dose (Vr100- Vr110) increased two-fold based between CT7 and CT60 evaluations (0.04 cc (0.06) Vs 0.08 (0.07) cc, respectively, p 5 0.06) compared to 0 cc for intraoperative plan.
Abstracts / Brachytherapy 9 (2010) S23eS102 Conclusions: Based on our experience, albeit limited data, it appears that for 131Cs implants intraoperative TRUS and post-seed CT plan parameters correlate significantly for implant volume parameters and weakly for prostate dose parameters. This could be the result of post-seed CT timing, edema effects and importantly due to prostate contouring uncertainty between TRUS and CT images. While there is no consensus yet on the optimal timing of post seed imaging for 131Cs implants, our study has also shown that there is a tendency for rectal dose increase with elapsed time. We strongly believe that post-seed imaging at the beginning and at the end of active dose delivery period may very well be necessary to get an accurate picture for short-lived 131Cs implants compared to one-time post-seed imaging widely practiced for 125I implants.
PO41 Body Fat Distribution, Waist Circumference and Body Mass Index in Permanent Seed Prostate Brachytherapy Daniel Taussky, M.D., Catherine Ji, Sebastien Clavel, M.D., David Donath, M.D. Radiation Oncology, Centre Hospitalier de l’Universite´ de Montre´al, Montreal, QC, Canada. Purpose: Recent studies have shown that obesity is associated with more aggressive prostate cancer variants and a higher prostate specific antigen (PSA) recurrence following prostatectomy. The aim of this study is to analyze the influence of body mass index (BMI) and the distribution of adipose tissue on clinical pretreatment variables and PSA evolution post 125 I prostate brachytherapy. Materials and Methods: We studied 59 men with low risk or ‘low tier’’ intermediate risk (maximum one intermediate risk feature) prostate cancer who had undergone 125I radioactive seed implantation as monotherapy. Inclusion criteria were an absence of hormonal therapy or external beam radiotherapy, a minimum of 8 months of followup and at least 3 followup PSA values. We calculated the BMI (kg/m2), waist circumference and the quotient between visceral and subcutaneous fat (VF/SF) measured on computed tomography at the iliac crest level. To analyze the influence of anthropometric measures on post-brachytherapy PSA evolution, we divided the patients into 2 groups: 1) rapid PSA descent post-brachytherapy to !0.5 ng/mL in the first 12 months following brachytherapy (n 5 28); 2) slow PSA descent postbrachytherapy to !0.50 ng/mL and a followup of >24 months (n 5 23) or a PSA bounce of >0.50 ng/mL (n 5 6). The influence of those anthropometric measures on pretreatment PSA, prostate volume and number of positive biopsies were calculated using Spearman correlation coefficient. Differences between the 3? post-brachytherapy outcome groups were analyzed using the Pearson chi-square and Fisher’s exact test. Relative risk estimate was calculated to measure of the strength of the association between the presence of a factor and the occurrence of an event. All tests were two-tailed. Results: There was an influence of the different anthropometric measures on pretreatment characteristics; there was a positive correlation between VF/SF and the PSA before treatment (r 5 0.282, p 5 0.029); and waist circumference with the number of positive biopsies (r 5 0.374, p 5 0.004). VS/SF, BMI and waist circumference were not different between both post-brachytherapy PSA-outcome groups (p>0.439). The following factors were associated with being in the slow descent group: younger patients (less than the median age of 65 years), p 5 0.003, relative risk (RR) 2.256 (95% confidence interval (CI), 1.249-4.073) and prostates smaller than the median 41 cc, p 5 0.034, RR 0.550 (95%CI, 0.3200.944). All patients with a waist circumference of O100 cm were in the rapid descent group. Among the patients with a VF/SF O0.9, 83% were in the slow descent group. Conclusions: In this small pilot study, waist circumference and VF/SF were weakly correlated to pretreatment characteristics. There seems to be a tendency that an increase in visceral fat and waist circumference has an influence on the type of PSA response. Larger studies are needed to determine if anthropomorphic measures have a direct influence on postbrachytherapy PSA response.
S95
PO42 Hormonal Blockade for Salvage Treatment of PSA-Only Recurrent Prostate Cancer after Interstitial High-Dose-Rate Brachytherapy for Early Stage Prostate Cancer: 5-Year Followup in 25 Patients Rufus J. Mark, M.D.1, Robin Akins, M.D.2, Paul J. Anderson, M.D.1, Murali Nair, Ph.D1. 1Radiation Oncology, Joe Arrington Cancer Center, Lubbock, TX; 2Radiation Oncology, Wilford Hall Medical Center, Lackland Airforce Base, TX. Purpose: Salvage treatment of biochemical recurrence after radiation implant is a subject of considerable controversy. Management options include PSA surveillance, radical prostatectomy, cryosurgery, External Radiation Therapy (XRT), Intensity Modulated Radiation Therapy (IMRT), and Hormonal Blockade (HB). Complication risks after radical prostatectomy, cryosurgery, XRT and IMRT salvage can be significant. We present our results in 25 patients treated with HB for biochemical recurrence after High-dose-rate (HDR) implant. Materials and Methods: Between 1997 and 2009, 301 patients with T1 and T2 localized prostate underwent TRUS guided interstitial implant, under spinal anesthetic or local anesthetic. There were no Gleason Score or PSA exclusions. No patient received XRT, IMRT, or initial HB. Median Gleason Score was 7 (range: 4 to 10). Median PSA was 9.3 (2.7 to 39.8). At last followup, 36 patients had developed PSA only relapse. After a discussion of management options, 25 patients elected salvage treatment with intermittent HB, starting with Casodex. All patients started Casodex 50 mg qd with PSA !10. Results: With a median followup of 66 months (range: 6 months to 132 months), the PSA control rate on Casodex was 84% (21/25). Four patients have become refractory to Casodex, and were switched to Lupron. Two of these patients remain controlled on Lupron. One patient has entered a clinical trial for chemotherapy. One patient has died from metastatic prostate cancer. One patient developed bone metastases, which have cleared on Lupron. Side effects have been acceptable. One patient sustained a myocardial infarction, and a 2nd suffered a fractured hip. Conclusions: With median 5-year followup, HB appears to be a reasonable salvage option for patients experiencing a PSA-only relapse after HDR implant.
PO43 Previous Transurethral Resection of the Prostate Is Not a Contraindication for Interstitial High-Dose-Rate Brachytherapy for Prostate Cancer Rufus J. Mark, M.D.1, Paul J. Anderson, M.D.1, Robin S. Akins, M.D.2, Murali Nair, Ph.D.1 1Radiation Oncology, Joe Arrington Cancer Center, Lubbock, TX; 2Radiation Oncology, Wilford Hall Medical Center, Lackland Airforce Base, TX. Purpose: Transrectal ultrasound (TRUS)-guided interstitial implant for prostate cancer using low-dose-rate (LDR) and high-dose-rate (HDR) technique has been reported with results comparing favorably to surgery and external beam radiation therapy (EBRT). Previous TURP has been considered a relative contraindication for LDR permanent seed implant because of higher rates of urinary incontinence. There are little data on previous TURP and subsequent incontinence after HDR implant. We report our urinary incontinence results with HDR with or without previous TURP. Materials and Methods: Between 1997 and 2009, 410 patients with T1 and T2 localized prostate underwent TRUS guided interstitial implant. There were no Gleason score or PSA exclusions. After discussion of treatment options, 109 patients elected HDR Implant þ IMRT and 301 patients underwent HDR monotherapy. No patient received hormonal blockade. Median Gleason score was 7 (range: 4 to 10). Median PSA was 9.8 (0.60 to 39.8). IMRT treatment volume included the prostate þ seminal vesicles þ 2 cm margin. Implant treatment volumes ranged from 32 cm3 to 196 cm3. In patients who received IMRT þ HDR, 4500 cGy in 25 fractions was given via IMRT and 1650 cGy to 2000 cGy in 3 fractions