ESTRO 2020 Abstract book

S661 ESTRO 2020

and late genitourinary (GU) and gastrointestinal (GI) toxicity assessment was performed using Common Terminology Criteria for Adverse Events (CTCAE) v4.0. Any PSA level rise of≥0.2 or more above the post-radiotherapy nadir was considered biochemical progression. Assuming p values ≤0.05 as significant, Chi-squared test was applied for statistical analysis. Kaplan-Meier method and log-rank test were adopted for survival estimates. Results RESULTS: Acute GU toxicities were G1 in 44% and G2 in 4.8%, no G≥3 events occurred. For GI toxicity, we reported G1 in 32.7% and G2 in 19.7%. With a median follow-up of 25 months (10-60), late toxicity rates were G2 GI in 4.7% and G2 GU in 1.8%; we also observed G3 GU in 1.8% of cases, consisting of 2 patients surgically treated for incontinence correction. At statistical analysis, pelvic irradiation was found significantly associated with acute G2 GI adverse events (p=0031). Actuarial 2- and 3-years biochemical-free survival were respectively 88.9% and 74.2% for the entire population, while in a subgroup evaluation, no difference in terms of biochemical control was observed between adjuvant or salvage treatment (p=0.28). All patients are alive, except for one death by cerebrovascular disease, resulting in 2- and 3-years overall survival rates of both 97.9%. Conclusion CONCLUSIONS: In our series moderate hypofractionated post-operative RT with Helical Tomotherapy resulted in a low incidence of adverse events, also collecting excellent biochemical control rates. PO-1166 IMRT versus 3D-CRT in the treatment of prostate cancer: comparison of outcomes and toxicity. W. Guo 1 , Y.C. Sun 1 1 Hebei Province Cangzhou Hospital of Integrated Traditional and Western Medicine, Department of Radiation Oncology, Cangzhou, China Purpose or Objective Prostate cancer is one of the most common cancers in the world. The potential benefits of intensity modulated radiation therapy (IMRT) over three-dimensional conformal radiation therapy (3DCRT) for prostate cancer primary radiation therapy treatment have not yet been clarified. Therefore, this meta-analysis was conducted to assess whether IMRT could improve clinical outcomes in comparison with 3DCRT in patients diagnosed with Relevant studies were identified through searching related databases till December, 2018. Hazard ratio (HR) or risk ratio (RR) with its corresponding 95% confidence interval (CI) was used as pooled statistics for all analyses. Results The incidence of grade 2 or worse acute adverse gastrointestinal(GI) event was analyzed and the pooled data revealed a clear decreasing trend in the IMRT compared with 3DCRT (RR=0.62, 95% CI: 0.45-0.84, p =0.002). IMRT slightly increased the grade ≥ 2 acute genitourinary(GU) adverse event in comparison with the 3DCRT (RR=1.1, 95% CI: 1.02-1.19, p =0.015). The IMRT and the 3DCRT of patients showed no substantial differences in grade ≥ 2 late GI adverse event (RR =0.62, 95% CI: 0.36- 1.09, p =0.1). In those included studies, there was no significant difference between IMRT and 3DCRT in grade 2– 4 late GU adverse event (RR =1.08, 95% CI: 0.77-1.51, p =0.65). There was a significant difference in biochemical control favoring IMRT (RR =1.13, 95% CI: 1.05-1.22, p =0.002). IMRT showed modest increase in biochemical control in comparison with 3DCRT. Conclusion In general, based on the above results, IMRT should be considered as a better choice for the treatment of prostate cancer. More randomized controlled trials are needed to determine the subset of patients diagnosed with PCa. prostate cancer(PCa). Material and Methods

radiation therapy (MH-IMRT) regimen of 72 Gy in 30 fractions over 6 weeks in an East Asian population. Material and Methods The outcomes of 412 consecutive prostate cancer patients who received MH-IMRT between May 2007 and December 2012 were reviewed retrospectively. The median patient age was 70.9 (range, 50–84) years. According to the NCCN criteria, 41 (10.0%) patients were classified as low-risk, 150 (36.4%) as intermediate-risk, 185 (44.9%) as high-risk, and 36 (8.7%) as very high-risk. Neoadjuvant and adjuvant androgen deprivation therapy was delivered to 296 (71.8%) and 190 (46.2%) patients, respectively. Late gastrointestinal (GI) and genitourinary (GU) toxicity rates were evaluated according to the Common Terminology Criteria for Adverse Events ver. 3.0. The overall survival, biochemical relapse-free survival rate (bRFS), late GI toxicity, and GU toxicity rates were analyzed with the Kaplan–Meier method. Results The median follow-up duration was 71.5 (range, 1.4–124.8) months. The 5-year bRFS rate was 93.2%. For patients with low-risk, intermediate-risk, high-risk, and very high-risk disease, the 5-year bRFS rates were 100%, 93.9%, 93.6%, and 80.3%, respectively. The 5-year grade ≥2 late GI and GU toxicity rates were 3.3% and 4.5%, respectively. Conclusion The study results suggest an MH-IMRT regimen of 72 Gy in 30 fractions was effective and safe for the treatment of prostate cancer in an East Asian population. PO-1165 Toxicity and outcomes of postoperative hypofractionated Helical Tomotherapy for prostate cancer F. Cuccia 1 , G. Ferrera 2 , V. Serretta 3 , G. Mortellaro 2 , F. Verderame 4 , A. Lupo 5 , D. Cespuglio 2 , L. Ognibene 6 , G. De Gregorio 1 , E. Quartuccio 1 , A. Gioia 1 , M. La Vecchia 1 , N. Luca 1 , G. Trapani 1 , V. Valenti 1 , A. Tripoli 1 , A. Lo Casto 7 1 University of Palermo, Radiation Oncology School, Palermo, Italy ; 2 ARNAS Civico Hospital, Radiation Oncology, Palermo, Italy ; 3 University of Palermo, Department of Surgical- Oncological and Oral Sciences, Palermo, Italy ; 4 Hospital Vincenzo Cervello, Department of Hematology and Oncology, Palermo, Italy ; 5 ARNAS Civico Hospital, Urology, Palermo, Italy ; 6 San Gaetano Radiotherapy and Nuclear Medicine Center, Radiotherapy Unit, Bagheria PA, Italy ; 7 University of Palermo, Section of Radiology - Di.Bi.Med., Palermo, Italy Purpose or Objective PURPOSE: The role of hypofractionation in prostate cancer is well established for the definitive setting, while it is still investigational in the post-surgery scenario. The present study reports acute and late toxicities and biochemical control rates in a retrospective series of 107 patients with prostate cancer who were treated in the post-operative setting with moderate hypofractionation delivered by METHODS: From April 2013 to August 2018, 107 patients, with median age 68 years (range, 54-84), received post- operative radiotherapy, delivering to prostate bed a total dose of 63.8 Gy (EQD2=67.4 Gy) using 2.2 Gy fractions. Adjuvant treatment (n=54) was proposed within 6 months after surgery for patients with PSA ≤0.2 ng/ml in presence of adverse features like positive margins, extracapsular extension, seminal vesicles invasion or lymph nodal involvement. Salvage therapy (n=53) was delivered 6 months after prostatectomy in case of PSA≥0.2 ng/ml or for patients with persistent post-surgery PSA. In 67% of patients, in presence of pathological adverse features (pN+, inadequate lymph nodal dissection (<10 nodes), and/or Gleason Score>8) pelvic irradiation was administered with a median dose of 49.3 Gy (range, 48- 55.1 Gy) in conventional fractionation. Concurrent hormonal therapy was prescribed in 49.5% of cases. Acute Helical Tomotherapy. Material and Methods