The addition of oxaliplatin did not extend overall survival (OS) in patients with stage II and III colon cancer, but did extend OS in the subgroup aged younger than 70 years, found the US NSABP C-07 trial, published in the Journal of Clinical Oncology.

In the earlier MOSAIC trial, published in 2004, investigators showed that oxaliplatin added to fluorouracil (FU) and leucovorin (LV) significantly improved disease free survival (DFS) in patients with colon cancer, thereby establishing oxaliplatin as part of the standard of care for adjuvant treatment of early-stage colon cancer.

However, although there was a survival benefit for stage II and III patients combined, on further analysis the benefit was restricted to patients with stage III disease. Additionally a pooled analysis of recent trials, including MOSAIC, suggested that the benefits may be restricted to patients younger than 70 years.

In the current study Greg Yothers and colleagues, from the University of Pittsburgh (PA, USA), set out to investigate whether the effects of oxaliplatin varied in selected patient subsets. In the study 2,409 patients with stage II or III colon cancer who had undergone potentially curative surgical resection were randomly assigned to either FULV (n=1,209) or FLOX (FULV plus oxaliplatin, n=320).

Results showed that at eight years follow up 362 patients died in the FULV group versus 320 patients in the FLOX group (HR 0.88 95% CI 0.75-1.02, p=.08). Additionally at eight years 503 disease free survival event s occurred on FULV versus 432 on FLOX (HR 0.82, 95% CI 0.72-0.93; P.002).

Furthermore, the study showed that the effects of oxaliplatin did not differ by stage of disease, but did differ according to age group. Overall survival of patients taking oxaliplatin was found to be significantly better for those aged under 70 in comparison with those over 70 (P =.039).

"The use of oxaliplatin with fluoropyrimidine therapy is appropriate for most patients with stage III colon cancer and perhaps selected patients with high-risk stage II colon cancer. In patients of advanced age, caution is warranted in selecting patients for oxaliplatin therapy," write the authors. Consideration, they add, should be given to the patient's overall state of health and potential for tolerating adverse events.

Source: G Yothers, M J O'Connell, CJ Allegra, et al. Oxaliplatin as adjuvant therapy for colon cancer: updated results of NSABP C-07 trial, including survival and subset analyses. Journal of Clinical Oncology 2011, 28: 3768- 3774.