[The efficacy and safety of surgical treatment after neoadjuvant chemotherapy for cT4N+ colon cancer]

Objective: To evaluate the safety and efficacy of surgical treatment after neoadjuvant chemotherapy (NCT) for patients with cT4N+ colon cancer, and to explore whether the indication of NCT for colon cancer can be extended from cT4b to cT4N+ . Methods: The clinical data of 40 patients with cT4N+ colon cancer who underwent neoadjuvant chemotherapy followed by surgical treatment was retrospectively analyzed. The safety of neoadjuvant chemotherapy, surgical complications, R0 resection rate, tumor regression grade and prognosis were evaluated. Results: Of the 40 patients, 23 were male and 17 were female; the median age was 57 years old. All patients were well tolerated with chemotherapy, and only one case (1/40, 2.5%) had grade 3 chemotherapy-related adverse event. They all underwent surgery after chemotherapy, and 95.0% (38/40) achieved microscopically clear resection (R0). Of the 11 patients with cT4b, 54.5% (6/11) had undergone multivisceral resection (MVR). Postoperative pathological results showed that 12 patients had moderate to severe tumor regression, including one(1/40, 2.5%) achieved pathologic complete response (pCR). 29(72.5%) and 22 (55.0%) patients achieved down-staging of tumor T stage and N stage, respectively. The occurrence of surgical complications was 22.5% (9/40), including one case of anastomotic leakage (1/40, 2.5%). The 3-year disease-free survival and overall survival of the whole group were 75.0% and 80.0%, respectively. Conclusion: Surgery after neoadjuvant chemotherapy is safe and effective for patients with cT4N+ colon cancer, therefore indications for neoadjuvant chemotherapy for advanced colon cancer can be extended to cT4N+ stage.