Prognostic importance of tumour deposits with and without concurrent lymph node metastases in patients with stage III colon cancer.

BACKGROUND: Tumour deposits (TD) are associated with poor prognosis in patients with colon cancer. However, the current staging system only acknowledges TD in patients without lymph node metastases (LNM). This study investigated the prognostic impact of TD with or without LNM in patients with stage III colon cancer. METHODS: This was a national retrospective cohort study using the Danish Colorectal Cancer Group database, including patients with stage III colon cancer who underwent curative surgery between 2017 and 2022. Patients were stratified into 3 groups: TD alone; LNM alone; and TD and LNM. The primary endpoint was overall survival (OS). RESULTS: Of the 18 395 patients registered during the study period, 10 241 underwent surgery with curative intent and 9807 had a TD assessment. Of the 3543 stage III CRC patients included, 1091 had TD (30.8%). Of these, 884 had TD and LNM (25.0%), whereas 207 had TD alone (5.8%). Patients with TD and LNM had significantly poorer survival than those with LNM alone (5-year OS 52.2% versus 69.2%; P < 0.001). On subgroup analyses, the presence of TD was associated with poorer OS across all N categories. On multivariable analysis, TD was independently associated with all-cause mortality (hazard ratio 1.25; 95% confidence interval 1.08 to 1.43; P = 0.002). Patients with TD only were significantly less likely to receive adjuvant chemotherapy than those with LNM or TD and LNM (42.5% versus 52.2% and 55.9%, respectively; P = 0.002). CONCLUSION: TD are common in patients with stage III colon cancer and are associated with poorer prognosis across all N categories.