Updated analysis of SWOG-directed Intergroup Study 0116: A phase III trial of adjuvant radiochemotherapy versus observation after curative gastric cancer resection

Journal of Clinical Oncology, 05/17/2012

Smalley SR et al. – Intergroup 0116 (INT-0116) demonstrates strong persistent benefit from adjuvant radiochemotherapy. Toxicities, including second malignancies, appear acceptable, given the magnitude of RFS and OS improvement. LRF reduction may account for the majority of overall relapse reduction. Adjuvant radiochemotherapy remains a rational standard therapy for curatively resected gastric cancer with primaries T3 or greater and/or positive nodes.

Methods

  • In all, 559 patients with primaries >/= T3 and/or node-positive gastric cancer were randomly assigned to observation versus radiochemotherapy after R0 resection.
  • Fluorouracil and leucovorin were administered before, during, and after radiotherapy.
  • Radiotherapy was given to all LRF sites to a dose of 45 Gy.

Results

  • Overall survival (OS) and relapse-free survival (RFS) data demonstrate continued strong benefit from postoperative radiochemotherapy.
  • The hazard ratio (HR) for OS is 1.32 (95% CI, 1.10 to 1.60; P = .0046). The HR for RFS is 1.51 (95% CI, 1.25 to 1.83; P < .001).
  • Adjuvant radiochemotherapy produced substantial reduction in both overall relapse and locoregional relapse.
  • Second malignancies were observed in 21 patients with radiotherapy versus eight with observation (P = .21).
  • Subset analyses show robust treatment benefit in most subsets, with the exception of patients with diffuse histology who exhibited minimal nonsignificant treatment effect.

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