Retrospective analysis of a Bi-National Colorectal Cancer Audit to characterize stage II colon cancer patients who were offered adjuvant chemotherapy.

Background: Adjuvant chemotherapy for stage II colon cancer is a controversial area with treatment often reserved for patients with high-risk clinicopathological features. The aim of this study was to characterize which patients with stage II disease were offered adjuvant chemotherapy in an Australian and New Zealand setting.

Methods: Data was retrospectively collected from the prospectively maintained Bi-National Colorectal Cancer Audit. Data from all patients with their first episode of stage II colon cancer from January 2007 to January 2019 were included.

Results: A total of 3763 patients were identified in the Bi-National Colorectal Cancer Audit database with stage II colon cancer, of which 715 were offered chemotherapy (19%). Patients were at significant greater odds of being offered chemotherapy for stage II disease if they were <55 years old, from an urban area, discussed in a multidisciplinary team (MDT) meeting, had a greater operative urgency, a lower American Society of Anesthesiologists score, had a T4 tumour or had less than 12 lymph nodes harvested.

Conclusion: In Australia and New Zealand the appropriate patients with high-risk features are more likely to be offered chemotherapy in line with current guideline recommendations; however, this may not be the case for regional patients. A large proportion of patients were not discussed at MDT meeting- given the decision to provide adjuvant chemotherapy for stage II disease remains a controversial area, and the likely small survival benefit offered by adjuvant chemotherapy, appropriate patient selection is critical and best discussed in an MDT setting.