ESTRO 2021 Abstract Book

S648

ESTRO 2021

and IGABT plans were revised, including delineation of the concerned organ on each CBCT, to allow detailed dosimetric analysis. Clinical efficacy (local failure-free- (LRFS), distant metastasis-free-(DMFS), regional failure -free (RFFS) cancer-specific-(CCS) and overall survival (OS)) was assessed by the Kaplan-Meier analysis complemented with Aalen-Johansen competing risk evaluation. Late side effects were scored using CTCAEv4.0. Results In total, 66 nodes (range:1-6/pts, average volume: 3.20 cm 3 , r:0.8-25.3) were boosted. Dose constraints for CTV-N D98 and PTV-N D98 were achieved in 91% and 83% of the nodes, while for organs at risks they were fulfilled in ≥ 96% of the cases. During the evaluation of 650 CBCTs only two nodes in ≤3 fractions (for the same patient) were not completely covered by PTV-N. At 3 months follow-up (FUP) all cases showed regression on imaging, including 18 pts (70%) with PET/CT, where complete metabolic regression was detected in 12/18 (67%) pts. After a median FUP of 25 months (3-52) there were no nodal failure/progression either in the boosted or in the elective RT regions. The two-years actuarial/crude rates of OS/CSS/DMFS/LFFS were 90/80, 95/88, 100/92, 90/92% respectively, in alignment with the slightly worse competing risk incidence (Figure 1). Eighty-nine percent of patients received ≥ 4 cycles of cisplatin with six ≥ Gr.3 hematologic side effect. One patient with PAO RT developed Grade 2 duodenal ulcer which fully recovered after conservative treatment. There was only one Gr.3 sigmoiditis with accompanying stenosis requiring elective surgical removal. In this case, both EBRT and IGABT plan respected the dose-constraints even at „worse-case” scenario for individual sigmoid locations.

Conclusion CovP based nodal SIB boost proved to be feasible providing excellent nodal control with low rate of late toxicity confiming its place as a standard of care approach for LAPCC.

PD-0817 Months and severity Score(MOSES)- A new approach to summarize adverse events in oncological trials N. Ranjan 1 , S. Chopra 2 , A. Mangaj 3 , S. Kannan 4 , T. Dora 5 , R. Engineer 1 , U. Mahantshetty 5 , L. Gurram 1 , P. Mittal 6 , J. Ghosh 7 , A. Maheshwari 8 , T. Shylasree 9 , S. Gupta 10 1 Tata Memorial Centre, Radiation oncology, Mumbai, India; 2 ACTREC, Tata Memorial Centre, Radiation Oncology, Mumbai, India; 3 MPCT hospital, Radiation oncology, Mumbai, India; 4 ACTREC, Tata Memorial Centre, Epidemiology and Clinical Trials Unit, Mumbai, India; 5 Homi Bhabha cancer hospital, Vizag, Radiation oncology, Vizag, India; 6 Tata Memorial Centre, Radiation Oncology, Mumbai, India; 7 Tata Memorial Centre, Medical oncology, Mumbai, India; 8 Tata memorial Centre, Gynae surgical oncology, Mumbai, India; 9 Tata Memorial Centre, Gynae surgical oncology, Mumbai, India; 10 ACTREC, Tata Memorial Centre, Medical oncology, Mumbai, India Purpose or Objective Toxicity reporting in oncology trials uses RTOG or CTCAE for adverse event reporting and captures only the maximum grade with no correlation with either temporal course or multiplicity of toxicity. We therefore propose a scoring method that takes severity and duration of toxicity into account (MOSES-Months and Severity Score) and compare it with conventional CTCAE maximum grade approach for accuracy in predicting symptomatic QOL using EORTC QLQ C30 and Cx24 considering patient reported outcomes as gold standard. Materials and Methods For the purpose of the study, patients recruited into prospective phase 3 randomized trial of postoperative IMRT (NCT01279135) were included. CTCAE grade was available at a predetermined interval as per trial protocol along with QOL. A total of six different toxicities that had a corresponding QOL question item were included for evaluation (Diarrhea, abdominal pain, anorexia, urinary incontinence, urinary frequency and Fatigue). Time weighted scores i.e. MOSES was calculated for individual toxicities (CTCAE grade score x proportionate time of follow up) and cumulative MOSES across all toxicities was determined by summating individual toxicity MOSES for all six toxicities included in study. QOL data was categorized as either substantial symptomatic QOL (symptomatic QOL for 50 % or higher number of follow ups) or not. Symptomatic QOL is taken as any score of more than one given by patients to specific QOL questions. ROC analysis was performed