Experts Establish Optimal Durations of CAPOX and FOLFOX for High-Risk CRC

Treatment durations of 3 months and 6 months for capecitabine plus oxaliplatin (CAPOX) or fluorouracil, leucovorin, and oxaliplatin (FOLFOX) therapy, respectively, are optimal for patients with high-risk, stage II colorectal cancer (CRC), according to findings from the TOSCA trial (JAMA Oncol. 2020 Feb 13. Epub ahead of print).

“The addition of oxaliplatin to the standard 6-month fluorouracil-based adjuvant chemotherapy in stage II colorectal cancer has been reported to reduce the risk of relapse although it does not increase survival,” explained Fausto Petrelli, MD, Medical Oncology Unit, ASST Bergamo Ovest, Treviglio, Italy, and co-investigators.

Dr Petrelli et al sought to determine the noninferiority and toxic effects of 3 months versus 6 months of oxaliplatin-based adjuvant chemotherapy plus CAPOX or FOLFOX to figure out the optimal treatment durations of each.

A total of 1254 patients with stage II, resected CRC who had been randomized to receive 3 months or 6 months of CAPOX or FOLFOX were included in the analysis.

A hazard ratio (HR) of at least 1.2 between the 3-month and 6-month chemotherapy arms was set to reject the null hypothesis of noninferiority.

The median follow-up time frame was 62 months. For the 3-month arm, 5-year relapse-free survival (RFS) was 82.2% versus 88.2% in the 6-month arm, with an estimated HR of 1.41 (95% CI, 1.05-1.89; P = .86 for noninferiority).

With CAPOX, the 5-year RFS was similar between both treatment arms, whereas with FOLFOX, the 6-month treatment arm had an 8.56% better 5-year RFS than the 3-month arm. Of note, the rate of neurotoxicity was approximately 5 times lower with the 3-month versus 6-month regimen.

“In the 3-month arm, the treatment was significantly less toxic than in the 6-month arm. Noninferiority was not shown for 5-year [RFS],” Dr Petrelli and colleagues said.

“However, a possible regimen effect was observed, suggesting that either 3 months of CAPOX or 6 months of FOLFOX therapy can be used whenever an oxaliplatin doublet is indicated for treatment of patients with stage II [CRC],” they concluded.—Kaitlyn Manasterski