Prognosis of a Heterogeneous TRG Pathological Response to Neoadjuvant Chemotherapy in Patients who Undergo Resection for Colorectal Liver Metastases

Optimal management of colorectal liver metastasis (CRLM) is based on a combination of chemotherapy and surgical resection. The tumor regression grade (TRG) score is a histological scoring system to evaluate response to chemotherapy. The prognosis of a heterogeneous response in cases of multiple metastases has not been evaluated according to the TRG score. All patients who underwent liver resection for multiple CRLM after neoadjuvant chemotherapy in two tertiary centers from January 2015 to April 2019 were retrospectively included. Oncological characteristics and outcome between TRG 1–2–3 (good response group), TRG 4–5 (poor response group) and heterogeneous TRG (good and poor TRG among different lesions within the same patient) groups were compared. Among the 327 patients included, 134 (41.0