Purpose: American Society of Clinical Oncology (ASCO) guidelines define high-risk prognostic features (HRFs) in stage II colon cancer and recommend limiting adjuvant chemotherapy to patients with HRFs. We evaluated the extent to which HRFs influenced decisions on adjuvant chemotherapy before and after publication of the guidelines.

Patients and methods: We reviewed data from 100 consecutive patients with stage II colon cancer resected between January 2000 and June 2007. Practice pattern in the pre-guideline era (2000 through 2004) was compared with the post-guideline era (2005-2007).

Results: The median age of the cohort was 65.8 years. A total of 60 patients had > or = 1 HRF. Overall, 38% of the patients with HRFs did not receive chemotherapy; 37.5% without HRFs did. Seventy-one percent of the patients given adjuvant chemotherapy had HRFs versus 48% of the patients not given chemotherapy. There was no association between the presence/absence of HRFs and chemotherapy (P = .25). The association between number of HRFs per individual and chemotherapy was significant (P = .0255). Bowel obstruction and T4 disease were the only individual HRFs significantly associated with chemotherapy (P = .0059 and .0294, respectively). A significant drop in use of chemotherapy for all patients occurred after publication of the guidelines, but this was caused mostly by a drop in treatment for patients with HRFs from 80% to 36% (P = .001).

Conclusion: Decisions for or against adjuvant chemotherapy did not adhere completely to ASCO guidelines. Publication of the guidelines led to a significant drop in appropriate use of adjuvant chemotherapy in high-risk patients.