Pathological response grade of colorectal liver metastases treated with neoadjuvant chemotherapy

Background: The complete resection of liver metastases from colorectal cancer is the major determinant of longterm survival. The effectiveness of current chemotherapy regimens has made treatment algorithms more flexible and resulted in many different options. Recently, the pathological response to chemotherapy has emerged as another important prognostic marker. Different systems have been used to grade the pathological response in these patients. Methods: This study prospectively evaluates the prognostic value of the pathological response grade (PRG) in liver metastases treated with neoadjuvant chemotherapy. Results: Between 2002 and 2006, 50 patients were treated with a sandwich chemotherapy regimen and underwent liver resection. Complete resection was achieved in 45 patients (90%). A strong pathological response to chemotherapy (<10% viable tumour cells in all lesions) was seen in 17 patients (34%). It was associated with a statistically significant longer overall survival (P = 0.019) and was also identified on multivariate analysis as an independent predictor of survival (odds ratio = 243). Conclusions: This pilot study demonstrates the prognostic potential of the PRG, which could be used clinically to select patients for an aggressive multimodal adjuvant algorithm. Larger multicentre studies are required to validate this particular grading system. The keys to longterm survival are resectability and chemo-responsiveness.