Abstract Book

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ESTRO 37

multivariate Cox regression analysis was used to assess differences between groups. Results Mean age at diagnosis was 65 years (42-80). All patients underwent radical prostatectomy combined with pelvic lymphadenectomy in 47.1% of cases. Adjuvant RT was performed in 113 patients and salvage RT in 183 (9 for local recurrence). The distribution of patients by pT stage was pT2a-b(30.3%), pT2c (35%), pT3(29%) and pT4(2.3%). Upgrade in Gleason score between biopsy and prostatectomy was experienced by 46.7% of patients. Positive surgical margins were reported in 56.5% of cases. Neoadjuvant androgen ablation before surgery was given to 36.5%. Mean pre-RT PSA of 0.46ng/ml (0-12.8) and mean dosis to surgical bed was of 70Gy (60-76Gy). Mean follow-up was 58.85 months (1-153 months). Overall survival at 5 and 10 years was 98.1% and 94.3%, respectively and BRFS at 5 and 10 years was 76.5% vs. 61.8%, respectively. The timing of RT (ART vs. SRT) and pre-RT PSA <0.5 ng/ml were significant predictors of longer BRFS. NLR median was 2,7 and we do not known any relation with outcome I our patients nor in adjuvant group and nor in salvage group Conclusion Postoperative radiation therapy provides excellent long- term overall survival with an aceptable BRFS. Pre-RT PSA <0.5ng/ml and adjuvant RT were predictors of better outcomes. NLR was not significantly associated with poor OS or recurrence-free survival or BRFS in our series. EP-1554 Treatment outcomes and toxicities of IMRT for more than 1000 Japanese patients with prostate cancer. H. Tanaka 1 , M. Ito 1 , T. Yamaguchi 1 , K. Esaki 1 , M. Hayashi 2 , S. Ogawa 2 , S. Kamei 3 , S. Ishihara 3 , F. Hyodo 1 , M. Matsuo 1 1 Gifu University, Radiology, Gifu, Japan 2 Kizawa Memorial Hospital, Radiation Oncology, Minokamo, Japan 3 Kizawa Memorial Hospital, Urology, Minokamo, Japan Purpose or Objective Studies on intensity-modulated radiation therapy (IMRT) for prostate cancer using a large sample size (> 1000) in Asia are yet to be conducted. All the large population studies were performed in Western countries.Because the physique and prostate glands of Asians are smaller than those of Westerners, the outcomes and toxicity might differ between Asian and Western patients. This study aimed to evaluate the treatment result of IMRT in a large number of Japanese patients with prostate cancer. Material and Methods A total of 1091 patients with localized prostate cancer were recruited between March 2006 and July 2014. All tumors were histologically confirmed as adenocarcinomas. The median patient age was 70 years (range, 38-80 years). The median PSA level at diagnosis was 8.53 ng/ml (range, 2.65-370.00 ng/ml). A total of 427 (39.1%), 331 (30.3%), 38 (3.5%), 125 (11.5%), 122 (11.2%), 39 (3.6%), and 9 (0.8%) patients had cT1c, T2a, T2b, T2c, T3a, T3b, and T4, respectively. The patients had a Gleason Score (GS) of ≤6 (n=316 [29.0%]), 7 (n=482 [44.2%], 8 (n=175 [16.0%]), 9 (n=104 [9.5%]), and 10 (n=14 [1.3%]).The patients were stratified into low- (n=205 [18.8%]), intermediate- (n=450 [41.2%]), high- (n=345 [31.6%]), very high-risk (n=91 [8.3%]) groups according to the National Comprehensive Cancer Network classification. All patients were irradiated via IMRT at a dose of 74-78 Gy with or without androgen-deprivation

therapy. The mean follow-up period was 50 months (range, 2-120 months). Median age 73 (38-80) Median PSA 8.53 (2.65-370.0) T stage < T1c 427 T2a 331 T2b 38 T2c 125 T3a 122 T3b 39 T3 9 GS ≤ 6 316 7 482 8 175 9 104 10 14 NCCN risk group Low 205 Intermediate 450 High 345 Very High 91 ADT use Yes 646 No 445 Results The biochemical failure-free rate (BFFR), the clinical failure-free rate, and the overall survival rate at the 5- year follow-up for all patients was 91.3%, 96.2%, 99.1%, respectively. In univariate analysis, the prostate-specific antigen (PSA) levels (≤20 vs. >20 ng/ml) were significantly correlated with BFFR. A trend toward higher BFFR was noted in patients with a Gleason score (GS) of ≤7 than in patients with GS ≥8. In multivariate analysis, only PSA (≤20 vs. >20 ng/ml) was significantly correlated with BFFR. The cumulative incidence rate of gastrointestinal and genitourinary toxicity (≥grade 2) at the 5-year follow-up was 11.4% and 4.3%, respectively.

Conclusion The findings of this study indicate that IMRT is well tolerated and is associated with both good long-term tumor control and excellent outcomes in patients with localized prostate cancer.