The characteristics and long-term survival of patients with colorectal liver metastases with pathological complete response after chemotherapy

Purpose: Preoperative chemotherapy is widely used for colorectal liver metastasis (CRLM). Pathological complete response (PCR) after chemotherapy indicates complete tumor regression and an extremely favorable prognosis. This study aimed to explore the characteristics and long-term survival of CRLM patients with pCR, who underwent surgery after preoperative chemotherapy. Methods: We retrospectively analyzed the clinical data of 494 CRLM patients who underwent hepatectomy after preoperative chemotherapy between January 2006 and January 2019. pCR was defined as the absence of any cancer cells on pathological examination. Results: Thirty (6.07%) patients achieved pCR after preoperative chemotherapy; 70% patients who achieved pCR did not experience recurrence and were cured after hepatectomy. The long-term prognosis of patients with pCR was extremely favorable, with 10-year overall and disease-free survivals of 85.2% and 73.7%, respectively; these were significantly better than those of patients without pCR (31.3% and 15.2%, respectively). Liver metastases <3 cm, preoperative carcinoembryonic antigen level ≤20 ng/mL, primary T stage 1-2, and right-sided primary tumors were independent predictors for pCR. Conclusion: pCR occurred in 6% of patients with CRLM after preoperative chemotherapy. Patients with a smaller tumor burden are more likely to benefit from chemotherapy and achieve pCR.