Proceedings of the 49th Annual ASTRO Meeting
2216
Short-term Hypofractionated Adjuvant Radiotherapy With Helicoidal Tomotherapy After Radical Prostatectomy: Planning Data and Toxicity Results
C. Cozzarini1, C. Fiorino1, N. Di Muzio1, R. Valdagni2, A. Salonia1, F. Alongi1, S. Broggi1, P. Rigatti1, R. Calandrino1, F. Fazio1 1
San Raffaele H Scientific Institute, Milan, Italy, 2Direzione Scientifica, National Institute of Cancer, Milan, Italy
Purpose/Objective(s): To report on planning and toxicity findings of hypofractionated adjuvant RT with helical Tomotherapy (HTT) after radical retropubic prostatectomy (RRP) for prostate carcinoma (pCa). Materials/Methods: 50 consecutive patients (pts) previously submitted to RRP for a pT2R1, pT3a/pT3b (n = 15, 32 and 3, respectively), R0/R1 pN0 pCa, were enrolled from January 2005 to March 2006 in a Phase I-II trial to receive 58 Gy/20 fraction in 4 weeks on the tumoral bed. Applying the linear quadratic model without any repopulation correction, the 2 Gy equivalent dose (EQD2) corresponding to our scheme ranges between 62 and 73 Gy for a/b ranging from 10 to 1.5. Main endpoint of the study was to confirm that this schedule did not increase the risk of grade 2–3 acute/late sequelae and that of biochemical failure when compared to our Institutional experience with conventionally fractionated 3DCRT (68–72 Gy, 1.8 Gy/fr; n = 153 pts). A patient-reported assessment of erectile and urinary functions at baseline, at 3-month follow-up date (3-m), and every 6 months thereafter (6-m, 12-m, and so on) was also activated. Results: Concerning planning data, excellent coverage of PTV and sparing of rectum, bladder and femoral heads were reached: the fraction of PTV receiving a dose .55 Gy was between 96% and 99% and Dmax ranged between 59 and 63 Gy. The sparing of the rectum was particularly relevant: Dmean ranged between 21 and 31 Gy; median value of V40 was 25%. Median follow-up was 21 months (range 11–27). Acute G2-3 genitourinary (GU) RTOG toxicities and acute G2 upper gastrointestinal sequelae (uGI) were similar (GU 14% vs 16%; uGI 4% vs 7%) in HTT and 3DCRT groups, respectively; acute G2 proctitis were 0% vs 9% in HTT and 3DCRT group (p \ 0.05), respectively. Similarly, late Grade $2 GI sequelae were 0% vs 8.5% (p \ 0.05). Concerning late GU sequelae, there were two Grade 2 and four Grade 3 (urethral stricture requiring dilatation) RTOG toxicities after HTT: the cumulative risk of Grade $2 late GU toxicity (12%) was similar to that observed in the 3DCRT group (21/153, 14%; dilatation for urethral stricture in 12/153, 8%). Thus far, the crude incidence of urethral stricture requiring dilatation after hypofractionated HTT (8%) seems comparable to that reported after surgery alone. The ANOVA demonstrated that IIEF-erectile function domain score was not significantly decreased throughout the follow-up dates (4.3 ± 5.3 vs 4.1 ± 6.3 vs 2.1 ± 2.0 vs 10.9 ± 8.8, respectively at baseline, at 3-m, at 6-m, and at 12-m of follow-up; F = 2.296; p = 0.07). Similarly, IPSS values were not significantly increased during the same 12-m period (14.3 ± 8.2 vs 13.4 ± 8.8 vs 8.4 ± 4.7 vs 13.8 ± 8.5, respectively at baseline, 3-m, 6-m, 12-m follow-up; F = 1.995; p = 0.12). At the moment of the present analysis, all pts are bNED. Conclusions: A moderately hypofractionated regimen (58 Gy/20 fractions) with HTT post-RRP is feasible and safe. Grade 2 acute and late proctitis were significantly reduced compared to our high-dose conventionally fractionated 3DCRT experience. Author Disclosure: C. Cozzarini, None; C. Fiorino, None; N. Di Muzio, None; R. Valdagni, None; A. Salonia, None; F. Alongi, None; S. Broggi, None; P. Rigatti, None; R. Calandrino, None; F. Fazio, None.
2217
Magnetic Resonance Image Guided Salvage Brachytherapy Following Radiation in Select Men who Initially Presented With Favorable-risk Prostate Cancer: A Prospective Phase II Study
W. W. Suh1, M. Chen2, P. L. Nguyen1, C. M. Tempany3, G. S. Steele3, M. Albert1, R. Cormack1, D. L. Carr-Locke3, R. Bleday3, A. V. D’Amico1 1 Dana-Farber/Brigham & Women’s Cancer Center, Boston, MA, 2University of Connecticut, Storrs, CT, 3Brigham & Women’s Hospital, Boston, MA Purpose/Objective(s): To prospectively evaluate the late gastrointestinal (GI) and genitourinary (GU) toxicity and prostate-specific antigen (PSA) control of magnetic-resonance imaging (MRI)-guided brachytherapy used as salvage for radiation therapy (RT) failure. Materials/Methods: From 10/00 to 10/05, 25 men with a rising PSA and biopsy-proven intraprostatic cancer at least 2 years after initial RT (13 external beam, 12 brachytherapy) who had favorable clinical features (Gleason score #7, PSA \10, negative pelvic and bone imaging), received MRI-guided salvage brachytherapy to a minimum peripheral dose of 137 Gray on a Phase I/II protocol. The Kaplan-Meier method was used to estimate the rates of treatment toxicity and cancer control. Results: Median follow-up was 47 months. The 4-year estimate of grade 3 or 4 GI/GU toxicity was 30%. Thirteen percent of patients required a colostomy and/or urostomy to repair a fistula. An interval \4.5 years between radiation courses was associated with both outcomes with hazard ratio of 12.0 (95% CI = 1.4 to 100; p = 0.02) for grade 3 or 4 toxicity and 25.0 (95% CI = 1.1 to 529; p = 0.04) for colostomy and/or urostomy. The PSA control, using the Phoenix definition, was 70% at 4-years. Conclusions: MRI-guided salvage brachytherapy in select men based on presenting characteristics and post-failure PSA kinetics can achieve high PSA control rates, but complications requiring surgical intervention may occur in 10 to 15% of men. Prospective randomized studies are needed to characterize the relative cancer control and toxicity following all forms of salvage local therapy. Author Disclosure: W.W. Suh, None; M. Chen, None; P.L. Nguyen, None; C.M. Tempany, None; G.S. Steele, None; M. Albert, None; R. Cormack, None; D.L. Carr-Locke, None; R. Bleday, None; A.V. D’Amico, None.
2218
High Dose Rate (HDR) Brachytherapy Boost for Prostate Cancer Gives High Control Rate
J. P. Flynn, D. A. Kelly, T. Brookover Cancer Treatment Centers of America, Tulsa, OK Purpose/Objective(s): Men who are trying to choose a treatment for prostate cancer are faced with balancing the perceived cure rates and toxicity rates for the various treatment options. High dose rate (HDR) brachytherapy is a modern treatment that delivers
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