Current clinical practice of adjuvant chemotherapy for patients with 'high-risk' Stage II colorectal cancer in Japan: a questionnaire survey in the JCOG Study Group.

While the major Western guidelines recommend adjuvant chemotherapy for patients having Stage II colorectal cancer (CRC) with 'high-risk' features, e.g., pT4 and lymphovascular involvement, the survival benefit has not been confirmed. To understand the actual clinical practice for this patient subgroup in Japan, we performed a questionnaire survey of specialist institutions regarding two topics: institutional policy of adjuvant chemotherapy, and the percentage of patients receiving adjuvant chemotherapy among 'high-risk' Stage II CRC patients. Among the 55 responders out of 60 institutions (response rate, 91.7%), 80.0% did not routinely administer adjuvant chemotherapy for 'high-risk' Stage II patients. The median percentage of 'high-risk' Stage II patients receiving adjuvant chemotherapy was 25%, with ≤30% in 35 institutions, and >60% in 12. In summary, performance of adjuvant chemotherapy for patients with 'high-risk' Stage II CRC varied substantially, even among these specialist institutions, and a majority of patients received no adjuvant chemotherapy.