[Adjuvant treatment of colon cancer MOSAIC study's main results]

Oxaliplatin in combination with 5-fluorouracil/leucovorin (LV5FU) improves the response rate and survival of patients with metastatic colorectal cancer. The objective of the Mosaic study was to evaluate the efficacy of this association in the adjuvant treatment of stage II and III colon cancer. This international study, including 2,246 patients, compared the efficacy of standard treatment with LV5FU2 alone to that of oxaliplatin-LV5FU (Folfox4 regimen) following R0 resection of the primary tumour. Both treatments were administered every two weeks for six months. At 3-year follow-up, the risk of relapse was decreased by 23% in the Folfox4 group (p = 0.002). The protocol was well tolerated, with an identical overall mortality during treatment (0.5%) in both groups. The main specific complication, peripheral sensory neuropathy was reversible in the great majority of cases. A new analysis at 4-year follow-up (median 48.6 months) confirmed the superior efficacy of the Folfox4 regimen compared to the standard treatment, the reduction in relapse risk being 24% (p = 0.0008). On the strength of these results, oxaliplatin was granted a marketing authorization for the indication adjuvant treatment of stage III colon cancer. Based on the data currently available, physicians should consider adjuvant treatment for stage II patients, making each individual decision for treatment on a case-by-case basis.