Compliance and Toxicity of Total Neoadjuvant Therapy for Rectal Cancer: A Secondary Analysis of the OPRA Trial

Abstract

Patients with locally advanced rectal cancer treated with total neoadjuvant therapy (TNT) may achieve organ preservation without a compromise to oncologic outcomes. However, reports on patient compliance with TNT and with treatment-related toxicities are limited. The OPRA trial assessed organ preservation rates and oncologic outcomes in patients with clinical stage II/III rectal adenocarcinoma randomized to induction chemotherapy followed by chemoradiation (INCT-CRT) or chemoradiation followed by consolidation chemotherapy (CRT-CNCT). Systemic chemotherapy consisted of 8 cycles (16 weeks) of fluorouracil, leucovorin, and oxaliplatin (FOLFOX) or 5 cycles (15 weeks) of capecitabine and oxaliplatin (CAPEOX). Patients received >4500 cGy of radiation with sensitizing capecitabine or fluorouracil. In this report, we compare compliance and treatment-related toxicity in patients receiving INCT-CRT versus CRT-CNCT. Additionally, we evaluate the association of compliance to chemotherapy, compliance to chemoradiation, and toxicity with organ preservation and disease-free survival (DFS). Of the 324 patients randomized, fewer patients started chemoradiation in the INCT-CRT group compared with the CRT-CNCT group (93% vs 98%, P=.03), and fewer patients started systemic chemotherapy in the CRT-CNCT group compared with the INCT-CRT group (94% vs 99%, P=.04). Order of TNT did not affect the ability to complete all intended cycles of FOLFOX (86% INCT-CRT vs 83% CRT-CNCT, P=.60) or CAPEOX (74% INCT-CRT vs 77% CRT-CNCT, P=.80). A total of 97% of INCT and 98% of CRT-CNCT patients received >4500 cGy radiation (P=.93). Sixty-four patients (41%) treated with INCT-CRT and 57 CRT-CNCT patients (34%) experienced a grade 3+ adverse event (P=.30). Compliance and toxicity were not associated with organ preservation or DFS. We identified only minor differences in treatment compliance between patients treated with INCT-CRT and CRT-CNCT. No difference in adverse events was observed between groups. Treatment compliance and toxicity did not correlate with organ preservation rates or DFS.