NEW YORK (Reuters Health) – In patients receiving first-line treatment for metastatic colon cancer, planned complete discontinuation of chemotherapy had a negative impact on duration of disease control and progression-free survival in the multicenter GERCOR OPTIMOX2 study.

The objectives of discontinuing chemotherapy include avoiding the toxicity of oxaliplatin and improving patients’ quality of life, the authors explain in the September 28th Journal of Clinical Oncology.

Dr. Aimery de Gramont from Hopital Saint-Antoine in Paris and colleagues randomized 202 patients to either a maintenance arm — six cycles of folinic acid, fluorouracil, and oxaliplatin (FOLFOX) followed by leucovorin and fluorouracil until progression – or a chemotherapy-free interval arm, with no treatment after the six FOLFOX cycles. In both groups, FOLFOX was resumed when progression developed.

The median duration of disease control was 13.1 months in the maintenance group, significantly longer than the 9.2 months in the chemotherapy discontinuation group (9.2 months) and representing a 29% reduction in the risk of oxaliplatin failure, the authors said.

The median duration of progression-free survival was also longer in the maintenance group (8.6 months) than in the chemotherapy discontinuation group (6.6 months), according to the report.

Median survival and objective tumor response rates were similar in the 2 groups.

Objective response rates after reintroduction of FOLFOX were similar between the groups, the researchers note.

The researchers say, however, that despite the results of the study, “we believe that chemotherapy discontinuation could be safely considered for selected patients, but the chemotherapy-free interval cannot be prescheduled before therapy commences, because individual responses cannot be predicted.”

“Thus,” the authors conclude, “the optimal strategy in patients with metastatic colorectal cancer remains to be defined in a heterogeneous population for whom different goals must be pursued: a high response rate in the subgroup amenable to surgery in case of good tumor response or in the subgroup of poor prognosis, sequential therapy in patients with asymptomatic disease, and now chemotherapy-free intervals in another subgroup of patients that requires further characterization.”

Reference:
J Clin Oncol 2009.