Current Management of T1 Colon Cancer in Denmark: A Nationwide Cohort Study.

ABSTRACT

OBJECTIVE: To describe the management of T1 colon cancer in a retrospective study of a national cancer registry. BACKGROUND: There is increasing interest in the potential of local excision (LE) as an organ-preserving treatment for early colon cancer. However, accurate identification of patients who may have lymph node metastases (LNM) and require further surgery is a major challenge. METHODS: Patients diagnosed with T1 colon cancer in Denmark from 2016 to 2020 were included and divided according to treatment polypectomy (referred to as LE), upfront colectomy and completion colectomy. Primary outcome was the proportion of patients diagnosed by LE. Secondary outcomes included the rate of LNM, the association of histopathological risk factors with LNM, and overall survival. RESULTS: 1,749 patients were included, and 1,022 patients (58.4%) underwent initial LE. The rate of R1 margins after initial LE was 31.0%. Colectomy was performed in 1,160 patients (upfront in 727, completion in 433), of whom 58.3% had pT1 cancer. The rate of LNM was 11.5%. Rates of LNM were similar in patients undergoing upfront or completion colectomy (10.2% vs 12.4%, P=0.392), and in patients with any single histopathological risk factor compared to those with none (8.9% vs 10.6%, P=0.565). Although overall survival was significantly shorter in patients undergoing LE alone, no association between survival and treatment strategy was found on multivariable analysis. CONCLUSIONS: LE is the most common mode of diagnosis in patients with T1 colon cancer and does not negatively impact survival and postoperative outcomes. Current strategies to stratify patients to completion surgery appear insufficient, and more robust predictors are needed.