Efficacy of neoadjuvant chemotherapy in patients with high-risk resectable colorectal liver metastases

Background: The role of preoperative neoadjuvant chemotherapy (NAC) in patients with resectable colorectal liver metastases (CRLM) remains undetermined. This study aimed to assess the efficacy of NAC in patients with resectable CRLM, especially in high-risk subgroups for recurrence, with special reference to synchronicity and the CRLM grade in the Japanese classification system. Methods: A retrospective analysis of a multi-institutional cohort who was diagnosed with resectable CRLM was performed. CRLM was classified into three grades (A, B, and C) according to the combination of H stage (H1: ≤ 4 lesions and ≤ 5 cm, H2: ≥ 5 lesions or > 5 cm, H3: ≥ 5 lesions and > 5 cm), nodal status of the primary tumor (pN0/1: ≤ 3 metastases, pN2: ≥ 4 metastases), and the presence of resectable extrahepatic metastases. Results: Among 222 patients with resectable CRLM, 97 (43.7%) had synchronous CRLM. The surgical failure-free survival (SF-FS) of patients with synchronous CRLM (without NAC) was significantly worse than that of patients with metachronous CRLM (P = 0.0264). The SF-FS of patients with Grade B/C was also significantly worse than that of Grade A (P = 0.0058). Among the 53 patients with synchronous and Grade B/C CRLM, 31 were assigned to NAC, and all of them underwent liver surgery. In this high-risk subgroup, the SF-FS and OS in the NAC group were significantly better than those in the upfront surgery group (P < 0.0001 and P = 0.0004, respectively). Conclusions: Patients with synchronous and Grade B/C CRLM could be good candidates for indication of NAC.