ESTRO 36 Abstract Book

S721 ESTRO 36 2017 _______________________________________________________________________________________________

No 52% 48% Linfovascular invasion: -Yes -No 22% 78% Results All patients received complete treatment. There were no complications during marker placement. With a median follow-up of 3.7 months (range 1-13 months ), the RTOG/EORTC acute urinary toxicities were grade 1 in 34,7 % and grade 2 in 21,7 %. Neither urinary stress nor incontinence was influenced by radiation therapy. Maximal acute gastrointestinal toxicities were grade 1 in 13%. There was no adverse events ≥ grade 3. Conclusion Present Hypo-IMRT with IGRT schedule for irradiation of prostate bed after radical prostatectomy reduces the length of treatment by 2 week as compared to other treatment regimens commonly used, is feasible and well tolerated with no severe acute effects side. Longer follow- up is needed to determine late impact of if this low rate of acute toxicity and the biochemical control EP-1358 Prostate postoperative hypofractionated radiotherapy: a single institution experience with Tomo S. Gomellini 1 , B. Shima 1 , R. Barbara 1 , C. Caruso 1 , A.D. Andrulli 1 , U. De Pula 1 1 azienda ospedaliera san giovanni addolorata, specialità- radioterapia, roma, Italy Purpose or Objective During the last decades, many studies of hypofractionated radiotherapy have been published in the prostate cancer field, due to the stronger radiobiological evidences of a low alpha/beta ratio for the prostate cancer ranging around 1.5 , demonstrating a trend in improvement in the hypofractionated groups in terms of Local Control and Biochemical Control if compared to the standard fractionation, with a substantial equivalence of acute and late toxicities. Very few publications are at the moment available in the postoperative setting. This is a single institution experience with Tomotherapy of hypofractionated radiotherapy in adjuvant and salvage treatmens. We report the preliminary results of acute and late toxicities. Material and Methods Between February 2012 and October 2015 27 patients underwent an hypofractionated radiotherapy with Tomotherapy in our Institute. Seven pts received adjuvant treatment for the presence of risk factors for local relapse at hystological examination at the surgery, while 20 pts underwent a salvage radiotherapy for biochemical relapse after prostatectomy. All patients did a regimen in 23 fractions for a total dose of 57.5 Gy and 59.8 Gy. Patients characteristics are reported in table 1 Results The acute and late urinary and rectal toxicities have been evaluated by the use of the C.T.C.A.E. 4.02 and the SOMA- LENT modified Scales. We lost 2 patients during the follow up period (1 patients died for other cause and 1 patients was not found anymore).The acute and late toxicities are reported below. The acute GU-G2 and GI-G2 toxicities were 18.5% and 14.8% respectively. One patient (3.7%) experimented a subacute rectal toxicitiy ≥ G3, (dilatation for rectal substenosis within 6 months from the end of RT). The late GU-G2 and GI-G2 toxicities were 8% and 0% respectively. Only 1 patient (4%) had a urinary late G3 toxicity (urethral dilations for substenosis) while none patients had a rectal late toxicity ≥ G3. Conclusion Many of the randomized and not randomized trials regarding hypofractionation have been published in the elective treatment setting with very few datas available in the postoperative group with the alert for the acute and late toxicities reported in the different published series. Even if this is a very small experience with a limited number of patients, we had very few toxicities but future and larger series are necessary to better understand the

real impact of hypofractionated radiotherapy in postoperative prostate cancer setting. EP-1359 Pain response in a Population-based study of Radium-223 for Metastatic Prostate Cancer S. Tyldesley 1 , S. Parimi 2 , E. Tsang 3 , F. Bachand 4 , M. Aparicio 5 , G. Duncan 5 , K. Sunderland 6 , R. Olson 7 , H. Pai 8 , A. Alexander 8 , V. Lapointe 5 , K. Chi 9 1 BC Cancer Agency - Vancouver, Radiation Oncology, Vancouver, Canada 2 BC Cancer Agency, Medical Oncology, Victoria, Canada 3 BC Cancer Agency, Medical Oncology, Vancouver, Canada 4 BC Cancer Agency, Radiation Oncology, Kelowna, Canada 5 BC Cancer Agency, Radiation Oncology, Vancouver, Canada 6 BC Cancer Agency, Genitourinary Cancer Outcomes Unit, Vancouver, Canada 7 BC Cancer Agency, Radiation Oncology, Prince George, Canada 8 BC Cancer Agency, Radiation Oncology, Victoria, Canada 9 BC Cancer Agency, Medical Oncology, Viancouver, Canada Purpose or Objective Randomized trials have demonstrated the survival and quality of life benefit of Radium (Ra 223) for pts with Castration Resistant Prostate Cancer (CRPC) with symptomatic bone metastases. Alkaline Phosphatase (ALP) level and response is correlated with survival after Ra 223. The British Columbia Cancer Agency (BCCA) is the single provider of Ra223 in BC since 2013. The BCCA also has a provincial Prospective Outcomes and Support Initiative (POSI) using the Brief Pain Inventory (BPI). Objective: To assess the baseline pain, pain response, and relationship of pain response to ALP response in patients treated with Ra 223 at a population based level. Material and Methods All patients that started radium 223 between Sep 2013 and Feb 2016 had the required minimum potential to complete 6 cycles at time of analysis. Since June 2015, all patients treated with radium 223 completed POSI questionnaires including BPI at each visit. Pain medication was group as none, non, weak, or strong opiod; a change between groups was categorized as an increase or decrease. ALP and PSA were recorded at consult and prior to each Ra223 dose. A worst pain improvement of at least 2 units on the 10 point scale was considered a pain response. ALP response was defined as a >30% decrease from baseline. Correlation between pain and ALP response was assessed using a Phi statistic. Results 91 patients started Ra223 during the entire study period. 34 patients completed at least baseline BPI , and had at least one follow-up BPI. Of these cases, 90% had pain, 80% had a pain score of at least 3, and 26% scored at least 7 at baseline. Of those with baseline pain of 3 or higher, 37% had a pain improvement of at least 2 units during the course of Ra 223. Of these responding patients, 30% had also received EBRT during Ra223 course, and 90% had stable or improved pain medication group. The ALP response rate was the same in those with and without a pain response (Phi -0.12, p=0.96). Comparing participants with pain response <2 versus at least 2 units, the ALP response (>30%) was similar (58% vs 57%) (0.96). Of note, the median number of prior treatments for CRPCs (abiraterone, enzalutamide, chemotherapy or investigational agents) was 2 (with a range 0-5), reflecting a heavily pretreated cohort. Conclusion In this population based study of Ra 223, the vast majority of patients have pain at baseline. 37 % of patients had improvement of pain during Ra 223 treatment, although analysis was confounded by use of EBRT. No correlation