Conclusions: VD3 increases the sensitivity of PC3 cells to ionizing radiation. VD3 represses RelB transcription and suppresses the expression of RelB target genes in PC3 cells. Suppression of RelB expression may serve as an effective means to enhance the efficacy of radiation treatment for prostate cancer. Author Disclosure: Y. Xu, None; F. Fang, None; S. Josson, None; D. St. Clair, None; W. St. Clair, None. 2209 Intensity Modulated Radiation Therapy for Prostate Cancer: Preliminary Results on Treatment Morbidity Compared to 3-D Conformal Radiation Therapy A. V. Kirichenko, K. Ruth, E. M. Horwitz, M. K. Buyyounouski, S. J. Feigenberg, D. Y. Chen, A. Pollack Fox Chase Cancer Center, Philadelphia, PA Purpose/Objective(s): To compare treatment related morbidity between Intensity Modulated Radiation Therapy (IMRT) and 3-D conformal radiation therapy (3D-CRT) in patients treated for prostate cancer at a single institution between 1995 - 2004. Materials/Methods: There were 928 patients treated between 5/1995 - 8/2001 with 3-DCRT (median follow-up of 63.3 months) and 489 patients treated with IMRT between 8/2001 - 5/2004 (median follow-up of 29.9 months). The two cohorts of patients had similar T-stage, pretreatment PSA (median 8.2 ng/mL in the 3D-CRT group and 6.7 ng/mL in the IMRT group, and Gleason score. Androgen deprivation (AD) was given to 21% patients in the 3D-CRT group and 25% in the IMRT group. Other patient characteristics examined were diabetes (15%), irritable bowel syndrome (2%), TURP (10%), and BPH (12%), which were included in the multivariate analyses (MVAs). The prescription dose for IMRT ranged from 74 –78 Gy with 95% of the PTV receiving 100% of the dose. 3D-CRT patients received a median peripheral CTV dose of 72 Gy (range 70 –79 Gy) prescribed to 95% isodose line; patients were excluded if RT dose was  70 Gy. The IMRT and 3D-CRT groups were compared by Kaplan-Meier survival estimates, logistic regression and Cox proportional hazards regression MVA. The MVAs included pre-treatment PSA, Gleason score, T-stage, RT dose, treatment to the whole pelvis/lymph nodes, TURP, BPH, irritable bowel syndrome, diabetes, and AD therapy. Results: The patients were well matched for PSA, T-stage and Gleason score. Acute GU and GI toxicity did not differ between the IMRT and 3D-CRT patients. Larger treatment volumes were associated with increased acute toxicities; patients with whole pelvis 3D-CRT treatment or IMRT to the prostate plus lymph nodes were twice as likely to have acute toxicity compared to the smaller fields (HR=2.1, p0.0001). IMRT was associated with reduced late grade  2 GI toxicity (p=0.009 log rank test); the 3-year actuarial risk for late Grade  2 GI toxicity was 6.2% vs 10.4% for IMRT vs 3D-CRT. MVA showed IMRT patients were at decreased risk of GI reactions compared to 3D-CRT (HR = 0.6, p=0.0499). Larger treatment volume was the only other significant predictor of late GI toxicity (hazard ratio = 1.7, p=0.003). Late GU toxicity was slightly increased in IMRT patients in univariate analysis, but the difference was not significant (log rank p=0.06). The 3-year estimated GU toxicity rate was 8.4% vs 5.7% for IMRT vs 3D-CRT. After adjustment for significant predictors including TURP and BPH using Cox proportional hazards MVA, the IMRT vs 3D-CRT difference was not significant (p=0.11). Conclusions: Despite higher RT doses, patients treated with IMRT experienced less late GI toxicity compared with 3D-CRT patients. There was no detectable difference in late GU toxicity. Patients treated with both IMRT and 3D-CRT had favorable toxicity profiles overalls, which could be explained by the specifics of treatment technique. Author Disclosure: A.V. Kirichenko, None; K. Ruth, None; E.M. Horwitz, None; M.K. Buyyounouski, None; S.J. Feigenberg, None; D.Y. Chen, None; A. Pollack, Varian, B. Research Grant. 2210 The Prognostic Value of Survivin in Locally Advanced Prostate Cancer: A Study Based on RTOG 8610 M. Zhang 1 , A. Ho 2 , E. Hammond 3 , W. Sause 3 , M. Pilepich 4 , W. Shipley 1 , H. Sandler 5 , L. Khor 6 , A. Pollack 6 , A. Chakravarti 1 1 Massachusetts General Hospital, Boston, MA, 2 American College of Radiology, Philadelphia, PA, 3 LDS Hospital, Intermountain Health Care, Salt Lake City, UT, 4 University of California, Los Angeles, CA, 5 University of Michigan Medical Center, Ann Arbor, MI, 6 Fox Chase Cancer Center, Philadelphia, PA Purpose/Objective(s): Survivin is a member of the inhibitor of apoptosis family that has been implicated in both control of apoptosis and regulation of cell division. Survivin and three known splice variants (delta-Ex3, 2B, and 3B) can have both pro-survival and pro-death functions. Given that these Survivin isoforms can exist in distinct subcellular compartments and that isoform-specific antibodies have not demonstrated high reliability when used for immunohistochemistry in formalin-fixed tissues, we examined the prognostic value of both nuclear and cytoplasmic Survivin expression using an antibody sensitive to all Survivin isoforms in men with locally advanced prostate cancer who were enrolled in Radiation Therapy Oncology Group (RTOG) protocol 8610. Materials/Methods: RTOG 8610 was a phase III randomized study comparing the effect of radiotherapy (RT) plus short-term androgen deprivation (STAD) with RT alone. Of the 456 eligible and analyzable cases, 68 patients had suitably-stained tumor material for nuclear Survivin analysis and 65 patients for cytoplasmic Survivin. Nuclear and cytoplasmic expression levels of nuclear Survivin were determined by immunohistochemical staining using anti-Survivin polyclonal antibody (NOVUS). The Automated Cellular Imaging System (ACIS) was used to quantify the percentage of cells with Survivin immunostaining (Survivin ACIS Mean Index %) and the intensity of Survivin immunostaining (Survivin ACIS Intensity Score). Impact of Survivin expression on overall survival, local progression, distant metastasis, and disease-specific survival was examined using Cox proportional hazards model. Results: Higher levels of nuclear Survivin appeared to be associated with improved outcome in this patient population. Compared to those with nuclear Survivin ACIS Intensity Scores 191.2, those who had nuclear Survivin ACIS Intensity Scores 191.2 had significantly improved prostate cancer survival (p=0.05, hazard ratio=0.45). On multivariate analysis, nuclear Survivin ACIS Intensity Scores 191.2 were significantly associated with improved overall survival (p=0.02) and prostate cancer survival (p=0.02). In contrast, higher Mean Index % of cytoplasmic Survivin immunostaining was significantly S326 I. J. Radiation Oncology ● Biology ● Physics Volume 66, Number 3, Supplement, 2006