MOSAIC

Population

• Patients who had undergone curative resection for stage II or III colon cancer.

Intervention

Fluorouracil plus leucovorin with oxaliplatin for six months. Doses are not stated in the abstract.

Comparator

Fluorouracil plus leucovorin for six months. Doses are not stated in the abstract.

Key results

• 1123 patients were randomly assigned to each group.
• After a median follow-up of 37.9 months, a cancer-related event occurred in 237 patients (21.1%) with fluorouracil-leucovorin plus oxaliplatin versus 293 patients (26.1%) with fluorouracil-leucovorin (HR for recurrence 0.77; P=0.002).
• Three-year disease-free survival: 78.2% (95% CI 75.6-80.7) versus 72.9% (95% CI 70.2-75.7); P=0.002 by the stratified log-rank test.

Harms

• In the oxaliplatin group, febrile neutropenia was 1.8% and grade 3 sensory neuropathy was 12.4% during treatment, falling to 1.1% at one year. Comparator rates are not given.
• Gastrointestinal adverse effects were described as low in the oxaliplatin group, without counts.
• Six patients in each group died during treatment (0.5%).

Practice impact

• Add oxaliplatin to fluorouracil-leucovorin for adjuvant treatment after resection of stage III colon cancer, and consider it only for selected high-risk stage II disease, when the disease-free survival gain outweighs neuropathy risk.

Applicability

• Patients after curative resection of stage II or III colon cancer who can receive six months of oxaliplatin-containing therapy.

Limitations

• Overall survival is not reported in the abstract.
• Stage II and stage III are combined; no stage-specific estimates are given.
• The recurrence hazard ratio has no confidence interval in the abstract.
• Drug doses are not stated.

Common misinterpretations

• This is a disease-free survival result, not an overall-survival result.
• Do not cite a stage II-only benefit; the abstract does not split stages.
• Neuropathy rates are reported only for the oxaliplatin arm.