- Email: [email protected]
Hypofractionated SBRT Versus Conventionally Fractionated EBRT for Prostate Cancer: Comparison of PSA Slope and Nadir
S370
International Journal of Radiation Oncology Biology Physics
combinations of parameters that predict for each potential clinical outcome. Materials/Methods: A total of 2627 patients with prostate cancer were treated from June 1990 to March 2011 with either EBRT (median dose 81 Gy), LDR brachytherapy involving either I-125 or Pd-103, or a combination approach. Based on the NCCN risk categories, 43.6% had low risk, 28.7% had intermediate risk, and 27.7% had high risk disease. 47.4% of patients received Androgen Deprivation Therapy (ADT). BED calculations assume an alpha beta ratio of 2 and patients were treated with a BED of 91-327 Gy2 (median 200 Gy2). Patients were stratified into six outcome groups: 1) alive with no PSA failure, N Z 2066; 2) alive with PSA failure, N Z 132; 3) alive with metastatic disease, N Z 30; 4) dead with metastatic disease, N Z 46; 5) dead with PSA failure, N Z 64; 6) dead with no PSA failure, N Z 289. The median follow-up was 6.5 years (range, 2-21.5 years). The Phoenix definition of PSA failure was used. Univariate and multivariate multinomial logistic regression was used to determine the combination of risk factors that best predicts for placement in one of the five outcome groups relative to the reference group, alive with no evidence of PSA failure. Results: On univariate analysis, age, initial PSA, total BED, Gleason score (GS), and ADT each predicted for outcome group. These were used in multivariate models to identify combinations of predictors. Higher PSA (OR 1.03; p < .001), lower total BED (OR 1.02; p < .001), ADT use (OR 1.72; p Z .02), and higher GS (OR 2.86, p Z .002 for GS 8-10 compared to 6; OR 2.22, p Z .026 for GS 8-10 compared to 7) predicted for group 2. Higher GS predicted for group 3, though the result did not reach statistical significance (OR 3.10, p Z .088 for GS 8-10 compared to 6). Not surprisingly, older age predicted for placement in groups 4, 5, and 6 (OR 1.05, 1.05 and 1.12; p Z .031, .039, and < .001, respectively). In addition to older age, higher PSA (OR, 1.03, p < .001), lower total BED (OR 1.02, p < .001) and higher GS (OR 2.86, p < .001 for GS 8-10 compared to 6; OR 2.22, p < .001 for GS 8-10 compared to 7) predicted for group 4. This same set of variables predicted for group 5 (OR 1.03, p < .001; OR 1.03, p < .001; OR 6.50, p < .001; and OR 2.99, p Z .01, respectively). In addition to older age, lower total BED (OR 1.01, p < .001) predicted for group 6. Conclusions: The strongest predictors of biochemical control are Gleason Score, PSA, BED, and ADT. ADT use does not appear to confer a survival benefit whereas BED does for all outcomes involving death, including death with PSA failure, and death with metastatic disease. These results might be used as predictive models for these six possible outcomes. Author Disclosure: S.R. Blacksburg: None. S. Kerns: None. N.N. Stone: G. Consultant; Amgen, Ferring, Janssen, Diversified Conference Management, Prologics LLC, Niohn MediPhysics. R.G. Stock: None.
empty bladder by a transurethral catheter and simulated with 3 mm CT scan. PTV was created adding margins (5 mm lateral, anterior and posterior, 10 mm cranio-caudally) to the CTV (prostate and proximal seminal vesicles); MRI fusion (T2 phase) was used in the same position. Applying Timmerman protocol, we prescribed 45 Gy in 5 F to the 95% of the PTV and the 99% of this volume received the 90% of the dose (univ.surv.equ.dose 147.8 Gy). Dose constraints: Urethral lumen was surrounded with 2 mm for avoiding inside hotspots (no more than 105%). Rectal wall contour was divided in anterior (no more than 80%, dose max. 105% and 3 cc 90%) and posterior (dose max. 45%). The plans were realized with VMAT treatment planning system and radiation therapy was delivered with a HDMLC, through 2 VIMAT arcs, with 6 MV energy. Results: Mean follow-up was 7 months (range, 1-14 months). Acute side effects evaluated treatment unit through the CTCAE criteria were: G.I. toxicity (endoscopy 2 weeks after RT): G0 86%, G1 14%, G2 0%, G3 0%, and acute G.U. toxicity was G0 73%, G1 27%, G2 0%, G3 0%. The mean PTV volume was 70.6 cc (range, 31.8-157.7 cc) and mean gel volume injected was 10.9 cc (range, 3.8 cc-22.05 cc). Mean rectum-prostate displacement was: superiorly 12.9 mm half level 14.3 mm, inferiorly 9.3 mm. Anterior rectal volume mean dose was 15.3 Gy (range, 7.95-29.5 Gy). Correlation (R2 0.08) was found between the imparted energy to the rectal tissue and its maximum gel caused distance. Conclusions: Our preliminary data suggests that the use of Space-OAR gel can reduce dramatically the rectal mucosa acute toxicity because of his displacement far from the PTV, and allow to treat bigger PTV volume (more than 60 gr.) otherwise excluded in no-gel population; this allows to apply Timmerman SABR regimen in the planned time for a wider prostatic cancer patients, offering a well- tolerated short course of radiation therapy. We need more follow-up for testing the biochemical control and late toxicity. Author Disclosure: A. Tagliagambe: None. T. Torri: None. A. Tofani: None. G. Piacentini: None. V. Marchetti: None. S. Luxardo: None. G. Marcozzi: None. E. Lorenzini: None. V. Pepe: None. R. Timmerman: None.
2435 Phase 1 Study of Stereo-Ablative Radiation Therapy With the Use of SpaceOAR Hydrogel as Definitive Treatment of Prostate Cancer: Preliminary Experience A. Tagliagambe,1 T. Torri,1 A. Tofani,1 G. Piacentini,1 V. Marchetti,1 S. Luxardo,1 G. Marcozzi,1 E. Lorenzini,1 V. Pepe,1 and R. Timmerman2; 1 Civic Hospital of Carrara, Carrara, Italy, 2Southwestern University Medical Center, Dallas, TX Purpose/Objective(s): Ultrahypofractionation according to Timmerman experience with 9 Gy per fraction (F) times 5 (total 45 Gy in 2.5 weeks) is a feasible dose for the stereo-ablative treatment of prostate cancer, but potentially toxic for rectal mucosa. Materials/Methods: From November 2011 we selected 15 patients according with these criteria: Age < 80 years; P.S. 0-1; Stage T1a-T2b, Gleason score 3+3 with PSA 20 ng/mL or 7 with PSA 15 ng/mL. No mayor surgery/radiation therapy on pelvis; absence of ulcerative proctitis evaluated by endoscopy; no adenopathy detected by CT/MRI or extraprostatic abnormal uptake studied with Pet-choline scan. Space-Oar gel between anterior rectal wall and posterior prostate and 3 fiducial markers were implanted through a transperineal approach. Subsequently, each patient was immobilized with thermoplastic mask in a prone position and
2436 Hypofractionated SBRT Versus Conventionally Fractionated EBRT for Prostate Cancer: Comparison of PSA Slope and Nadir M. Anwar, V. Weinberg, A. Chang, I.J. Hsu, M. Roach, and A.R. Gottschalk; University of California San Francisco, San Francisco, CA Purpose/Objective(s): Patients with early stage prostate cancer face a challenge in selecting from a variety of curative radiation therapy options, including external beam radiation therapy (EBRT) and brachytherapy implants. To offer patients the shortened treatment time associated with brachytherapy, yet avoid a surgical procedure, patients have been prospectively treated with hypofractionated stereotactic body radiation therapy (SBRT) with dosimetry modeled after high dose rate (HDR) brachytherapy. While long term follow-up is needed to assess treatment efficacy, rapid post-treatment PSA decline and low PSA nadir have been associated with improved clinical outcomes. The purpose of this study was to compare the PSA response over time between conventionally fractionated EBRT and SBRT in newly diagnosed localized prostate cancer. Materials/Methods: One hundred four patients (pts) with low to lowintermediate risk prostate cancer (GS 3+3, PSA < 20 or 3+4, PSA < 15) treated with standard fractionated EBRT (> 70.2 Gy, < 76 Gy) without hormones to the prostate only were identified from a prospectively collected cohort of patients treated (1997-2006). Patients were excluded if they failed therapy by the Phoenix definition. All included pts had at least 1 year of follow-up and 3 serial PSAs. Out of 71 pts that were treated with SBRT to the prostate to 38 Gy in 4 daily fractions, 43 also met the same criteria. Of the eligible patients, 47 and 26 patients treated with EBRT and SBRT, respectively, had increasing PSA follow-up over the 3 years with a sufficient number to calculate the slope for each interval. PSA nadir and rate of change in PSA over time (e.g., slope) were calculated from the completion of RT to 1, 2 and 3 years post RT.
Volume 87 Number 2S Supplement 2013
Poster Viewing Abstracts S371
Results: The median PSA nadir and slope for patients treated with EBRT was 0.80, 0.50, 0.40 ng and 0.07, 0.02, 0.01 ng/mL/month for durations of 1, 2 and 3 years post-RT, respectively. Similarly, for SBRT, the median PSA nadir and slope were 0.70, 0.40, 0.24 ng and 0.09, 0.06, 0.05 ng/mL/ month. The PSA slope for SBRT was steeper than EBRT at 2 and 3 years following RT (p < 0.01 for each year), although similar during year 1. These results were also observed when limited to patients with more complete PSA follow-up each year. For this more complete subset, patients had a lower PSA nadir 3 years after treatment with SBRT that trended towards significance when compared to those treated with EBRT (p Z 0.07). Conclusions: Patients treated with hypofractionated SBRT experienced a more rapid and sustained decline in PSA 2 and 3 years following completion of RT than with EBRT, and in addition for those with continuous long term follow-up, a lower PSA nadir. This adds further support to a low a/b for prostate cancer, resulting in a higher bioequivalent dose with hypofractionation. Author Disclosure: M. Anwar: None. V. Weinberg: None. A. Chang: None. I.J. Hsu: None. M. Roach: None. A.R. Gottschalk: None.
2437 Influence of Vascular Comorbidities and Race on Erectile Dysfunction After Prostate Cancer Radiation Therapy Y. Wang,1 L. Tian,2 P. Rossi,2 D. Watkins-Bruner,2 W. Hsiao,3 S. Cooper,2 X. Yang,2 and A. Jani2; 1University of Tennessee Health Science Center College of Medicine, Memphis, TN, 2Department of Radiation Oncology, Emory University School of Medicine, Atlanta, GA, 3Department of Urology, Emory University School of Medicine, Atlanta, GA Purpose/Objective(s): Vascular comorbidities (VCs) (hypertension [HTN], diabetes [DM], and hyperlipidemia [HL]) are known factors related to erectile dysfunction (ED) in men. However, no data are yet available for the effects of VC on ED incidence after prostate-cancer radiation therapy (XRT). We analyzed the influence of VC on post-XRT ED, and further explored ED incidence by race. Materials/ Methods: We reviewed 732 charts of patients (267 white and 465 African American [AA]) who received prostate external beam radiation therapy (XRT and/or brachytherapy) with or without hormone therapy between 1999 and 2010. The number of pre-XRT VC (0, 1, 2, or 3) was determined by medical history and medication list. ED (defined by use of erectile aids or by documentation of moderate or high sexual dysfunction on patient history) was determined pre-XRT as well as 1, 2, and 4 years post-XRT. Results: ED incidence progressively increased from 22% pre-XRT to 58% 4 years post-XRT (p < 0.01). Additionally, ED incidence significantly increased with number of VC- 4-year incidence between patients with 1 vs 0 (p Z 0.02), 2 vs 0 (p < 0.01), 3 vs 0 (p < 0.01), 3 vs 1 (p < 0.01), and 3 vs 2 (p Z 0.04) VC (2 vs 1 VC was non-significant). Compared with the white patients, ED incidences were slightly higher for the AA group with 0, 1, 2 and 3 co-morbidities at 4 years follow-up (but statistically nonsignificant). Conclusions: The number of VC have a significant effect on development of post-XRT ED. Pre- and post-XRT ED appear to be independent of race
Poster Viewing Abstract 2437; Table and time-point
ED incidence for all patients by VC Post-XRT ED
Number of VCs 0 1 2 3 Overall
Pre-XRT ED
1 year
2 years
4 years
15% 19% 26% 35% 22%
39% 48% 55% 71% 52%
41% 55% 59% 73% 56%
44% 56% 63% 75% 58%
when number of VC are considered. Our results can be used to guide physicians in counseling patients on the incidence of ED by number of VC and as preliminary data for prospective efforts aimed at reducing post-XRT ED. Author Disclosure: Y. Wang: None. L. Tian: None. P. Rossi: None. D. Watkins-Bruner: None. W. Hsiao: None. S. Cooper: None. X. Yang: None. A. Jani: None.
2438 High-Risk Prostate Cancer: Radiation or Surgery? K. Stephans,1 R. Tendulkar,1 C. Reddy,1 A. Stephenson,1 E. Klein,1 P. Kupelian,2 and J. Ciezki1; 1Cleveland Clinic, Cleveland, OH, 2 University of California Los Angeles, Los Angeles, CA Purpose/Objective(s): High-risk prostate cancer (HRPCa) represents a heterogeneous population of patients. No randomized data is available comparing treatment with prostatectomy (RP) to external beam radiation (EBRT). This review of a large registry compares outcomes between RP and EBRT for HRPCa. Materials/Methods: A total of 1,555 patients with NCCN HRPCa and at least two post-treatment PSAs treated by either RP (n Z 900) or EBRT (biologically corrected dose of at least 78 Gy, n Z 655) between 1996 and 2010 were identified. Biochemical failure was defined as initiation of salvage therapy, or PSA >0.40 for RP and nadir + 2 for EBRT. Biochemical relapse free survival (bRFS) was compared using the log-rank test overall, and in subgroups of Gleason 6-7 elevated PSA (495 RP, 392 EBRT), Gleason 8 w PSA <10 (196 RP, 76 EBRT), Gleason 8 w PSA 10 (83 RP, 84 EBRT), Gleason 9-10 (126 RP, 103 EBRT), and cT3 (79 RP, 93 EBRT). Cox proportional hazards regression was done to identify factors associated with bRFS. Results: Median age was 64.2 (61.4 RP, 67.9 EBRT, p < 0.0001), median initial PSA 16.9 (13.5 RP, 21.7 EBRT, p < 0.0001), and Gleason score 8 42.9% (45.1% RP, 39.8% EBRT, p < 0.0001). Androgen deprivation therapy (ADT) was more common with EBRT (p<0.0001). ADT was given to 25% of RP patients (median duration 3 months, > 6 months in 4%), and 99% of EBRT patients (median duration 6 months, > 6 months in 27%, > 12 months in 16%). Median PSA follow-up was 53.3 months (39.8 RP, 72.2 EBRT, p < 0.0001), with a median of 7 PSA values for RP and 13 for EBRT (p < 0.0001). Overall, bRFS was statistically significantly improved for EBRT (p < 0.0001, HR 1.56). Allowing for resolution of some of the effect of ADT, 5-year bRFS was 61% versus 74%, and 10-year bRFS was 47% v 54%, both favoring EBRT. bRFS was also higher for EBRT in subgroups of Gl 6-7 w elevated PSA (p Z 0.002; 5year 67% v 77%), Gleason 8 w PSA 10 (p Z 0.020; 5y 40% v 59%), Gleason 9-10 (p Z 0.001; 5-year 48% v 68%), and cT3 patients (p Z 0.020; 5y 39% v 59%). There was no statistically significant difference for Gleason 8 w PSA < 10 (p Z 0.086; 5-year 63% v 80%). Other univariate correlates with bRFS were initial PSA, Gleason score (though no difference for Gleason 6 v 7), and clinical T3 disease. ADT use (p Z 0.27) and duration were not correlated with bRFS in univariate or multivariate analysis. All univariate predictors (initial PSA, Gleason, T stage, EBRT v RP) remained statistically significantly associated with bRFS on multivariate analysis. Conclusions: (1) bRFS was improved for HRPCa patients treated with EBRT compared to RP. (2) This was true for all examined sub-groups except Gleason 8 w PSA <10. (3) Numerical differences of at least 10% persisted at 5 years in all subgroups, a time point exceeding the typical duration of adjuvant ADT. (4) bRFS is potentially sensitive to the variable definitions of biochemical failure for EBRT and RP. (5) Assessment of prostate cancer specific mortality requires additional follow-up. Author Disclosure: K. Stephans: None. R. Tendulkar: None. C. Reddy: None. A. Stephenson: None. E. Klein: None. P. Kupelian: E. Research Grant; Varian Medical. F. Honoraria; Accuray, Siemens Medical, Varian Medical, ViewRay. O. Patent/License Fee/Copyright; Vision Tree. Q. Leadership; ViewRay. J. Ciezki: None.
International Journal of Radiation Oncology Biology Physics
combinations of parameters that predict for each potential clinical outcome. Materials/Methods: A total of 2627 patients with prostate cancer were treated from June 1990 to March 2011 with either EBRT (median dose 81 Gy), LDR brachytherapy involving either I-125 or Pd-103, or a combination approach. Based on the NCCN risk categories, 43.6% had low risk, 28.7% had intermediate risk, and 27.7% had high risk disease. 47.4% of patients received Androgen Deprivation Therapy (ADT). BED calculations assume an alpha beta ratio of 2 and patients were treated with a BED of 91-327 Gy2 (median 200 Gy2). Patients were stratified into six outcome groups: 1) alive with no PSA failure, N Z 2066; 2) alive with PSA failure, N Z 132; 3) alive with metastatic disease, N Z 30; 4) dead with metastatic disease, N Z 46; 5) dead with PSA failure, N Z 64; 6) dead with no PSA failure, N Z 289. The median follow-up was 6.5 years (range, 2-21.5 years). The Phoenix definition of PSA failure was used. Univariate and multivariate multinomial logistic regression was used to determine the combination of risk factors that best predicts for placement in one of the five outcome groups relative to the reference group, alive with no evidence of PSA failure. Results: On univariate analysis, age, initial PSA, total BED, Gleason score (GS), and ADT each predicted for outcome group. These were used in multivariate models to identify combinations of predictors. Higher PSA (OR 1.03; p < .001), lower total BED (OR 1.02; p < .001), ADT use (OR 1.72; p Z .02), and higher GS (OR 2.86, p Z .002 for GS 8-10 compared to 6; OR 2.22, p Z .026 for GS 8-10 compared to 7) predicted for group 2. Higher GS predicted for group 3, though the result did not reach statistical significance (OR 3.10, p Z .088 for GS 8-10 compared to 6). Not surprisingly, older age predicted for placement in groups 4, 5, and 6 (OR 1.05, 1.05 and 1.12; p Z .031, .039, and < .001, respectively). In addition to older age, higher PSA (OR, 1.03, p < .001), lower total BED (OR 1.02, p < .001) and higher GS (OR 2.86, p < .001 for GS 8-10 compared to 6; OR 2.22, p < .001 for GS 8-10 compared to 7) predicted for group 4. This same set of variables predicted for group 5 (OR 1.03, p < .001; OR 1.03, p < .001; OR 6.50, p < .001; and OR 2.99, p Z .01, respectively). In addition to older age, lower total BED (OR 1.01, p < .001) predicted for group 6. Conclusions: The strongest predictors of biochemical control are Gleason Score, PSA, BED, and ADT. ADT use does not appear to confer a survival benefit whereas BED does for all outcomes involving death, including death with PSA failure, and death with metastatic disease. These results might be used as predictive models for these six possible outcomes. Author Disclosure: S.R. Blacksburg: None. S. Kerns: None. N.N. Stone: G. Consultant; Amgen, Ferring, Janssen, Diversified Conference Management, Prologics LLC, Niohn MediPhysics. R.G. Stock: None.
empty bladder by a transurethral catheter and simulated with 3 mm CT scan. PTV was created adding margins (5 mm lateral, anterior and posterior, 10 mm cranio-caudally) to the CTV (prostate and proximal seminal vesicles); MRI fusion (T2 phase) was used in the same position. Applying Timmerman protocol, we prescribed 45 Gy in 5 F to the 95% of the PTV and the 99% of this volume received the 90% of the dose (univ.surv.equ.dose 147.8 Gy). Dose constraints: Urethral lumen was surrounded with 2 mm for avoiding inside hotspots (no more than 105%). Rectal wall contour was divided in anterior (no more than 80%, dose max. 105% and 3 cc 90%) and posterior (dose max. 45%). The plans were realized with VMAT treatment planning system and radiation therapy was delivered with a HDMLC, through 2 VIMAT arcs, with 6 MV energy. Results: Mean follow-up was 7 months (range, 1-14 months). Acute side effects evaluated treatment unit through the CTCAE criteria were: G.I. toxicity (endoscopy 2 weeks after RT): G0 86%, G1 14%, G2 0%, G3 0%, and acute G.U. toxicity was G0 73%, G1 27%, G2 0%, G3 0%. The mean PTV volume was 70.6 cc (range, 31.8-157.7 cc) and mean gel volume injected was 10.9 cc (range, 3.8 cc-22.05 cc). Mean rectum-prostate displacement was: superiorly 12.9 mm half level 14.3 mm, inferiorly 9.3 mm. Anterior rectal volume mean dose was 15.3 Gy (range, 7.95-29.5 Gy). Correlation (R2 0.08) was found between the imparted energy to the rectal tissue and its maximum gel caused distance. Conclusions: Our preliminary data suggests that the use of Space-OAR gel can reduce dramatically the rectal mucosa acute toxicity because of his displacement far from the PTV, and allow to treat bigger PTV volume (more than 60 gr.) otherwise excluded in no-gel population; this allows to apply Timmerman SABR regimen in the planned time for a wider prostatic cancer patients, offering a well- tolerated short course of radiation therapy. We need more follow-up for testing the biochemical control and late toxicity. Author Disclosure: A. Tagliagambe: None. T. Torri: None. A. Tofani: None. G. Piacentini: None. V. Marchetti: None. S. Luxardo: None. G. Marcozzi: None. E. Lorenzini: None. V. Pepe: None. R. Timmerman: None.
2435 Phase 1 Study of Stereo-Ablative Radiation Therapy With the Use of SpaceOAR Hydrogel as Definitive Treatment of Prostate Cancer: Preliminary Experience A. Tagliagambe,1 T. Torri,1 A. Tofani,1 G. Piacentini,1 V. Marchetti,1 S. Luxardo,1 G. Marcozzi,1 E. Lorenzini,1 V. Pepe,1 and R. Timmerman2; 1 Civic Hospital of Carrara, Carrara, Italy, 2Southwestern University Medical Center, Dallas, TX Purpose/Objective(s): Ultrahypofractionation according to Timmerman experience with 9 Gy per fraction (F) times 5 (total 45 Gy in 2.5 weeks) is a feasible dose for the stereo-ablative treatment of prostate cancer, but potentially toxic for rectal mucosa. Materials/Methods: From November 2011 we selected 15 patients according with these criteria: Age < 80 years; P.S. 0-1; Stage T1a-T2b, Gleason score 3+3 with PSA 20 ng/mL or 7 with PSA 15 ng/mL. No mayor surgery/radiation therapy on pelvis; absence of ulcerative proctitis evaluated by endoscopy; no adenopathy detected by CT/MRI or extraprostatic abnormal uptake studied with Pet-choline scan. Space-Oar gel between anterior rectal wall and posterior prostate and 3 fiducial markers were implanted through a transperineal approach. Subsequently, each patient was immobilized with thermoplastic mask in a prone position and
2436 Hypofractionated SBRT Versus Conventionally Fractionated EBRT for Prostate Cancer: Comparison of PSA Slope and Nadir M. Anwar, V. Weinberg, A. Chang, I.J. Hsu, M. Roach, and A.R. Gottschalk; University of California San Francisco, San Francisco, CA Purpose/Objective(s): Patients with early stage prostate cancer face a challenge in selecting from a variety of curative radiation therapy options, including external beam radiation therapy (EBRT) and brachytherapy implants. To offer patients the shortened treatment time associated with brachytherapy, yet avoid a surgical procedure, patients have been prospectively treated with hypofractionated stereotactic body radiation therapy (SBRT) with dosimetry modeled after high dose rate (HDR) brachytherapy. While long term follow-up is needed to assess treatment efficacy, rapid post-treatment PSA decline and low PSA nadir have been associated with improved clinical outcomes. The purpose of this study was to compare the PSA response over time between conventionally fractionated EBRT and SBRT in newly diagnosed localized prostate cancer. Materials/Methods: One hundred four patients (pts) with low to lowintermediate risk prostate cancer (GS 3+3, PSA < 20 or 3+4, PSA < 15) treated with standard fractionated EBRT (> 70.2 Gy, < 76 Gy) without hormones to the prostate only were identified from a prospectively collected cohort of patients treated (1997-2006). Patients were excluded if they failed therapy by the Phoenix definition. All included pts had at least 1 year of follow-up and 3 serial PSAs. Out of 71 pts that were treated with SBRT to the prostate to 38 Gy in 4 daily fractions, 43 also met the same criteria. Of the eligible patients, 47 and 26 patients treated with EBRT and SBRT, respectively, had increasing PSA follow-up over the 3 years with a sufficient number to calculate the slope for each interval. PSA nadir and rate of change in PSA over time (e.g., slope) were calculated from the completion of RT to 1, 2 and 3 years post RT.
Volume 87 Number 2S Supplement 2013
Poster Viewing Abstracts S371
Results: The median PSA nadir and slope for patients treated with EBRT was 0.80, 0.50, 0.40 ng and 0.07, 0.02, 0.01 ng/mL/month for durations of 1, 2 and 3 years post-RT, respectively. Similarly, for SBRT, the median PSA nadir and slope were 0.70, 0.40, 0.24 ng and 0.09, 0.06, 0.05 ng/mL/ month. The PSA slope for SBRT was steeper than EBRT at 2 and 3 years following RT (p < 0.01 for each year), although similar during year 1. These results were also observed when limited to patients with more complete PSA follow-up each year. For this more complete subset, patients had a lower PSA nadir 3 years after treatment with SBRT that trended towards significance when compared to those treated with EBRT (p Z 0.07). Conclusions: Patients treated with hypofractionated SBRT experienced a more rapid and sustained decline in PSA 2 and 3 years following completion of RT than with EBRT, and in addition for those with continuous long term follow-up, a lower PSA nadir. This adds further support to a low a/b for prostate cancer, resulting in a higher bioequivalent dose with hypofractionation. Author Disclosure: M. Anwar: None. V. Weinberg: None. A. Chang: None. I.J. Hsu: None. M. Roach: None. A.R. Gottschalk: None.
2437 Influence of Vascular Comorbidities and Race on Erectile Dysfunction After Prostate Cancer Radiation Therapy Y. Wang,1 L. Tian,2 P. Rossi,2 D. Watkins-Bruner,2 W. Hsiao,3 S. Cooper,2 X. Yang,2 and A. Jani2; 1University of Tennessee Health Science Center College of Medicine, Memphis, TN, 2Department of Radiation Oncology, Emory University School of Medicine, Atlanta, GA, 3Department of Urology, Emory University School of Medicine, Atlanta, GA Purpose/Objective(s): Vascular comorbidities (VCs) (hypertension [HTN], diabetes [DM], and hyperlipidemia [HL]) are known factors related to erectile dysfunction (ED) in men. However, no data are yet available for the effects of VC on ED incidence after prostate-cancer radiation therapy (XRT). We analyzed the influence of VC on post-XRT ED, and further explored ED incidence by race. Materials/ Methods: We reviewed 732 charts of patients (267 white and 465 African American [AA]) who received prostate external beam radiation therapy (XRT and/or brachytherapy) with or without hormone therapy between 1999 and 2010. The number of pre-XRT VC (0, 1, 2, or 3) was determined by medical history and medication list. ED (defined by use of erectile aids or by documentation of moderate or high sexual dysfunction on patient history) was determined pre-XRT as well as 1, 2, and 4 years post-XRT. Results: ED incidence progressively increased from 22% pre-XRT to 58% 4 years post-XRT (p < 0.01). Additionally, ED incidence significantly increased with number of VC- 4-year incidence between patients with 1 vs 0 (p Z 0.02), 2 vs 0 (p < 0.01), 3 vs 0 (p < 0.01), 3 vs 1 (p < 0.01), and 3 vs 2 (p Z 0.04) VC (2 vs 1 VC was non-significant). Compared with the white patients, ED incidences were slightly higher for the AA group with 0, 1, 2 and 3 co-morbidities at 4 years follow-up (but statistically nonsignificant). Conclusions: The number of VC have a significant effect on development of post-XRT ED. Pre- and post-XRT ED appear to be independent of race
Poster Viewing Abstract 2437; Table and time-point
ED incidence for all patients by VC Post-XRT ED
Number of VCs 0 1 2 3 Overall
Pre-XRT ED
1 year
2 years
4 years
15% 19% 26% 35% 22%
39% 48% 55% 71% 52%
41% 55% 59% 73% 56%
44% 56% 63% 75% 58%
when number of VC are considered. Our results can be used to guide physicians in counseling patients on the incidence of ED by number of VC and as preliminary data for prospective efforts aimed at reducing post-XRT ED. Author Disclosure: Y. Wang: None. L. Tian: None. P. Rossi: None. D. Watkins-Bruner: None. W. Hsiao: None. S. Cooper: None. X. Yang: None. A. Jani: None.
2438 High-Risk Prostate Cancer: Radiation or Surgery? K. Stephans,1 R. Tendulkar,1 C. Reddy,1 A. Stephenson,1 E. Klein,1 P. Kupelian,2 and J. Ciezki1; 1Cleveland Clinic, Cleveland, OH, 2 University of California Los Angeles, Los Angeles, CA Purpose/Objective(s): High-risk prostate cancer (HRPCa) represents a heterogeneous population of patients. No randomized data is available comparing treatment with prostatectomy (RP) to external beam radiation (EBRT). This review of a large registry compares outcomes between RP and EBRT for HRPCa. Materials/Methods: A total of 1,555 patients with NCCN HRPCa and at least two post-treatment PSAs treated by either RP (n Z 900) or EBRT (biologically corrected dose of at least 78 Gy, n Z 655) between 1996 and 2010 were identified. Biochemical failure was defined as initiation of salvage therapy, or PSA >0.40 for RP and nadir + 2 for EBRT. Biochemical relapse free survival (bRFS) was compared using the log-rank test overall, and in subgroups of Gleason 6-7 elevated PSA (495 RP, 392 EBRT), Gleason 8 w PSA <10 (196 RP, 76 EBRT), Gleason 8 w PSA 10 (83 RP, 84 EBRT), Gleason 9-10 (126 RP, 103 EBRT), and cT3 (79 RP, 93 EBRT). Cox proportional hazards regression was done to identify factors associated with bRFS. Results: Median age was 64.2 (61.4 RP, 67.9 EBRT, p < 0.0001), median initial PSA 16.9 (13.5 RP, 21.7 EBRT, p < 0.0001), and Gleason score 8 42.9% (45.1% RP, 39.8% EBRT, p < 0.0001). Androgen deprivation therapy (ADT) was more common with EBRT (p<0.0001). ADT was given to 25% of RP patients (median duration 3 months, > 6 months in 4%), and 99% of EBRT patients (median duration 6 months, > 6 months in 27%, > 12 months in 16%). Median PSA follow-up was 53.3 months (39.8 RP, 72.2 EBRT, p < 0.0001), with a median of 7 PSA values for RP and 13 for EBRT (p < 0.0001). Overall, bRFS was statistically significantly improved for EBRT (p < 0.0001, HR 1.56). Allowing for resolution of some of the effect of ADT, 5-year bRFS was 61% versus 74%, and 10-year bRFS was 47% v 54%, both favoring EBRT. bRFS was also higher for EBRT in subgroups of Gl 6-7 w elevated PSA (p Z 0.002; 5year 67% v 77%), Gleason 8 w PSA 10 (p Z 0.020; 5y 40% v 59%), Gleason 9-10 (p Z 0.001; 5-year 48% v 68%), and cT3 patients (p Z 0.020; 5y 39% v 59%). There was no statistically significant difference for Gleason 8 w PSA < 10 (p Z 0.086; 5-year 63% v 80%). Other univariate correlates with bRFS were initial PSA, Gleason score (though no difference for Gleason 6 v 7), and clinical T3 disease. ADT use (p Z 0.27) and duration were not correlated with bRFS in univariate or multivariate analysis. All univariate predictors (initial PSA, Gleason, T stage, EBRT v RP) remained statistically significantly associated with bRFS on multivariate analysis. Conclusions: (1) bRFS was improved for HRPCa patients treated with EBRT compared to RP. (2) This was true for all examined sub-groups except Gleason 8 w PSA <10. (3) Numerical differences of at least 10% persisted at 5 years in all subgroups, a time point exceeding the typical duration of adjuvant ADT. (4) bRFS is potentially sensitive to the variable definitions of biochemical failure for EBRT and RP. (5) Assessment of prostate cancer specific mortality requires additional follow-up. Author Disclosure: K. Stephans: None. R. Tendulkar: None. C. Reddy: None. A. Stephenson: None. E. Klein: None. P. Kupelian: E. Research Grant; Varian Medical. F. Honoraria; Accuray, Siemens Medical, Varian Medical, ViewRay. O. Patent/License Fee/Copyright; Vision Tree. Q. Leadership; ViewRay. J. Ciezki: None.