Intergroup randomized phase III study of adjuvant FOLFIRI, FOLFOX, or 5-FU/leucovorin for stage II/III rectal cancer: ECOG-ACRIN E3201.

BACKGROUND: Adjuvant 5-FU monotherapy was previously the standard treatment for stage II/III rectal cancer. This study compared adjuvant FOLFIRI, FOLFOX, and 5-FU/LV. METHODS: Eligible patients had T3-T4 N0 or Tany N1-3 rectal adenocarcinoma ≤12 cm from the anal verge and received pre-operative or postoperative 5-FU chemoradiotherapy (CRT). Patients were randomized to adjuvant FOLFIRI (8 cycles), FOLFOX (8 cycles), or 5-FU/LV weekly (6/8 weeks; 3 cycles). The trial planned to enroll 3,150 patients but was closed early following activation of an alternative adjuvant rectal cancer study including bevacizumab (E5204). The primary endpoint was overall survival (OS); secondary endpoints included disease-free survival (DFS), sphincter preservation, tolerability, and quality of life (QOL). RESULTS: The trial enrolled 225 patients (179 randomized) before early closure. Grade 3/4 toxicity occurred in 59%, with neutropenia, leukopenia, and diarrhea being the most common. At a median follow-up of 9.7 years, no significant OS or DFS differences were observed. The rate of sphincter preservation was numerically higher with FOLFIRI and FOLFOX versus 5-FU/LV, but the difference was not statistically significant. CONCLUSION: FOLFOX and FOLFIRI can be safely administered after CRT in rectal cancer patients safely with expected toxicities. Due to early trial closure and small sample size, the survival analysis was underpowered to detect a significant difference between regimens. CLINICALTRIALS.GOV IDENTIFIER: NCT00068692.