Pathological response of colorectal liver metastases treated after induction treatment.

Background: Mortality for colorectal cancer is mainly due to liver metastases, surgical resection remains the curative treatment and use of neoadjuvant therapy improves resectability of metastases. Pathological response is an important prognostic factor.

Aim: To evaluate tumor response by Tumor regression grade (TRG) according Rubbia-Brandt et al and correlation with survival. To establish chemotherapy-related liver injury.

Methods: Thrity-eight patients resected for colorectal cancer liver metastases after neoadjuvant chemotherapy were enrolled in this study. Tumor regression grade (TRG) according to Gradding Rubbia-Brandt et al. was evaluated.

Results: Sex ratio was 1.5 with an average age of was 55 years. Twenty-five patients were in stage IV (65.7% of patients with synchronous liver metastases). Overall survival was 62% at 12 months, 42% at 24 months and 21% at 36 months. Thirty-four patients (89.5%) received Oxaliplatin and nine (23.7%) irinotecan. Twenty patients (52.6%) had no histologic response (TRG 4 and 5), nine (23.7%) had a major response (TRG 1 and 2) and nine had a partial response (TRG3). Survival was more important with major pathologic response than with partial response or no response. No statistically significant relation was found between survival and the different types of response. Chemotherapy-related liver injury were present in 21 patients (55.2%).  Conclusions: Scoring system with three grades are currently recommanded to evaluate pathological response and new histopathological data are proposed. Larger studies are required to validate these items and their utility for therapeutic decisions.