ESTRO 36 Abstract Book

S691 ESTRO 36 2017 _______________________________________________________________________________________________

Prophylactic paraaortic irradiation is being increasingly advocated for patients of locally advanced cervical cancer. Up to 25% of patients with FDG avid pelvic lymph nodes harbor micro-metastases in paraaortic lymph nodes, corroborating the postulated benefit of prophylactic para- aortic irradiation. However, acute toxicity was a major limiting factor when 2-dimensional extended field radiotherapy planning was used with concurrent cisplatin. With the use of intensity modulated radiotherapy (IMRT) in the form of intensity modulated arc therapy (IMAT), doses to organs at risk could be successfully reduced, limiting the treatment related toxicities. The purpose of our study was to prospectively evaluate the tolerance and acute toxicity in patients of locally advanced cervical cancer undergoing prophylactic extended field paraaortic irradiation by IMAT, with concurrent cisplatin. Material and Methods Patients of FIGO stage IIB-IIIB cervical cancer with FDG avid pelvic lymph nodes,were prospectively accrued between 2014 and 2016. All patients received 45 Gy in 5 weeks to pelvic and paraaortic target volumes, with simultaneous integrated boost (SIB) of 55 Gy in 5 weeks to gross nodal disease by IMAT (Rapidarc TM ), with weekly concurrent cisplatin of 40 mg/m 2 , followed by intracavitary brachytherapy. Acute toxicity was monitored twice a week, using CTCAE v 4.03 for gastrointestinal (GI) and genitourinary (GU) toxicity, and RTOG criteria for hematological toxicity. Treatment interruptions were taken as a surrogate for tolerance. Descriptive statistics were used to evaluate acute toxicities; multivariate analysis was used to correlate the toxicities with doses to organs at risk. Results Out of the 15 patients recruited, treatment interruptions due to acute toxicity were observed in none. No grade 3 or 4 acute toxicity was reported in GI, GU or hematological domains. Among GI toxicities, vomiting and diarrhea of ≥ grade 2 were observed in 13.3%, while nausea, anorexia and dyspepsia of ≥ grade 2 were observed in 6%. Grade 1 proctitis was reported in 26%, while none had ≥ grade 2 proctitis. Only 6% of patients experienced grade 1 GU toxicity in the form of increased frequency and cystitis, while none had ≥ grade 2 toxicity. Hematological toxicity in the form of ≥ grade 2 anemia was observed in 46%, while 13.3% of patients had ≥ grade 2 leucopenia and 6% had ≥ grade 2 thrombocytopenia. On multivariate analysis, significant correlation was observed between volume of bowel bag receiving 45 Gy (median, 142 cc) and ≥ grade 2 vomiting (p=0.003). Other dosimetric correlates of toxicity were statistically insignificant. Conclusion Extended field prophylactic para-aortic irradiation with concurrent cisplatin is well tolerated in patients of locally advanced cervical cancer with FDG avid pelvic lymphnodes, treated with IMAT. While none of our patients experienced grade 3 or grade 4 toxicities in GI, GU or hematological domains, proportion of ≥ grade 2 toxicities was within acceptable levels. EP-1303 Clinical outcomes of patients with advanced cervical cancer and percutaneous nephrostomy : An audit R. Salunkhe 1 , S. Chopra 1 , S. Kulkarni 2 , R. Engineer 1 , U. Mahantshetty 1 , N. Shetty 2 , J. Ghosh 3 , S. Gupta 3 , S.K. Shrivastava 1 1 Tata Memorial Hospital, Radiation Oncology, Mumbai, India 2 Tata Memorial Hospital, Interventional Radiology, Mumbai, India 3 Tata Memorial Hospital, Medical Oncology, Mumbai, India

Conclusion Interference of the three different treatment modalities makes it very difficult to unravel dose-effect relations for this patient group. Internal motion of the organs could have induced mismatches between planned and irradiated EBRT dose. Despite interplay effects of Cisplatin and IGABT, we found some trends i.e. correlation of early weight loss with body V43Gy, severity of vomiting and diarrhea. Consequently, rescanning for the ART patient group is now rescheduled to week 4, to adapt EBRT to reduced body volume if necessary. For GU toxicity, we recommend the combination of daily bladder volume during EBRT and IGABT to be assessed with non-rigid analyses in a larger patient group. EP-1302 Acute toxicity of prophylactic para-aortic chemoradiation for cervical cancer treated in IMAT era N. Ballari 1 , B. Rai 1 , R. Miriyala 1 , A. Bahl 1 , B.R. Mittal 2 , S. Ghoshal 1 1 Post Graduate Institute of Medical Education and Research, Radiotherapy and Oncology, Chandigarh, India 2 Post Graduate Institute of Medical Education and Research, Nuclear Medicine, Chandigarh, India

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