Tumor deposits in stage III colon cancer

Colorectal cancer (CRC) remains one of the primary causes of cancer mortality worldwide (1). The tumor node metastasis (TNM) classification, which is based on tumor extent, lymph node involvement, and presence of distant metastasis, is still the most commonly used approach to inform patient prognostication and decision making in clinical management. This classification helps to stratify patients into different risk levels of cancer recurrence and survival after curative resection, and guides the appropriate use of systemic adjuvant therapy. Systemic adjuvant therapy can improve the overall survival of patients with stage III colon cancer by around 3–5%, but is associated with a risk of significant side effects and a small risk of death (2,3). Better stratification is therefore needed to distinguish between patients at higher risk of recurrence who are more likely to benefit from adjuvant therapy, and those at lower risk of recurrence who have a better chance of cure by surgery without adjuvant therapy.