colon cancer

Duration of Adjuvant Doublet Chemotherapy (3 Or 6 Months) in Patients with High-Risk Stage II Colorectal Cancer

Duration of Adjuvant Doublet Chemotherapy (3 Or 6 Months) in Patients with High-Risk Stage II Colorectal Cancer

In the January 13, 2021 issue of Journal of Clinical Oncology, Timothy J. and investigators report on 3 vs 6 months of adjuvant doublet chemotherapy in patients with high risk stage II colon cancer.

PURPOSE:

Investigators report on the long-term outcomes, across 4 studies in the international duration evaluation of adjuvant chemotherapy collaborative, in patients with high-risk stage II colon and rectal cancer, provided adjuvant treatment with either CAPOX or FOLFOX for either 3 or 6 months.

PATIENTS AND METHODS:

Patients were treated with either FOLFOX or CAPOX and randomized to either 3- or 6-months of treatment.  Disease free survival was the primary endpoint, and noninferiority of 3-month treatment was defined as a hazard ratio < 1.2-versus 6-month arm. For an 80% power detection at a one-sided type 1 error rate of 0.10, a total of 542 DFS events were needed.

RESULTS:

3,273 eligible patients were randomized to either 3- or 6-months of therapy with 62% receiving CAPOX and 38% FOLFOX regimens. There were 553 disease free survival events. 5-year disease-free survival was 80.7% and 83.9% for 3-month and 6-month treatment, respectively (HR, 1.17; 80% CI, 1.05 – 1.31; P (for noninferiority) .39). This was shown to cross the noninferiority limit of 1.2. The duration of effect appeared dependent on the chemotherapy regimen although a test of interaction was negative. HR for CAPOX was reported to be 1.02 (80% CI, 0.88 to 1.17), and HR for FOLFOX was reported to be 1.41 (80% CI, 1.18 to 1.68).

The authors concluded “ Although noninferiority has not been demonstrated in the overall population, the convenience, reduced toxicity, and cost of 3-month adjuvant CAPOX suggest it as a potential option for high-risk stage II colon cancer if oxaliplatin-based chemotherapy is suitable. The relative contribution of the factors used to define high-risk stage II disease needs better understanding.”

https://ascopubs.org/doi/full/10.1200/JCO.20.01330

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