ESTRO 2021 Abstract Book

S1032

ESTRO 2021

Medical Oncology, Mumbai, India; 7 Tata Memorial Hospital, Medical oncology, Mumbai, India; 8 Tata Memorial Hospital, Surgical oncology, Mumbai, India

Purpose or Objective The role of neoadjuvant chemo-radiotherapy (NACTRT) in upper rectal and recto-sigmoid cancers is controversial. Most of these patients receive upfront surgery followed by adjuvant chemotherapy. There is no randomized trial to compare the role of NACTRT vs upfront surgery in the upper rectum, to the best of our knowledge. The objective of this study is to compare the disease free survival and overall survival in patients treated with upfront surgery, with those who received NACTRT. Materials and Methods A retrospective analysis of the patients treated consecutively from the prospectively maintained database, having adenocarcinoma of upper rectum and recto-sigmoid junction, treated during 2013-2018, at our institute was done. The two groups compared were Group A (43 patients) who had received NACTRT and underwent surgery and Group B (37 patients) who underwent upfront surgery. Post surgery, patients in both groups received 4-6 cycles of adjuvant chemotherapy as indicated. The primary objective was to calculate disease free survival, and secondary objective was to calculate overall survival of both the groups. Results Out of the 80 patients, 43 had poor prognostic features and received NACTRT (Group A) and 37 (46%) who did not have high risk features, underwent upfront surgery (Group B). The T and N stage of group A was higher as compared to the patients of group B. The difference was significant in N stage (p=0.001). All 43 patients of group A had down-staging of the tumour on histopathology which was evaluated using Mandard tumour regression score, with 10 patients having complete pathological response. (TRG 1/5). In group A, 26 patients had Circumferential resection margin (CRM) positive on baseline MRI. After NACTRT, 23(88%) of these patients had CRM negative (p= 0.050). In Group A, 10 (23%) patients had recurrence, whereas in Arm B, 15(40.5%) (p=0.15) had recurrences. Local recurrences were similar in both the groups i.e. 2 in Group A and 6 in Group B (p=0.171). 23 (29%) of the 80 patients developed distant metastasis, 9 (21%) in Group A vs 15 (38%) in Group B (p=0.07). The median follow up was 45 months for both groups. The median follow up in the NACTRT arm was 52 months (range:13- 84 months) and that in the surgery arm was 46 months (range:1-78 months). There was a trend towards better disease free survival of Group A compared to Group B. Median DFS being 38 months (range: 6- 76 months) for Group A whereas it was 30 months (range: 4-73 months) for Group B (p=0.067). The median overall survival in arm A was 46 months (range: 15-82 months) and 37 months in Arm B (range: 3–73 months) (p=0.094). Treatment related toxicity was not significant in group A.