An updated scoring system for prediction of survival after resection of colorectal liver metastases: addition of KRAS status as an important risk modifier

Colorectal liver metastases (CRLM) were traditionally associated with a very poor prognosis after resection, with some historical series reporting 5-year survival rates as low as 14% for completely resected multiple metastases (1). However, as modern chemotherapy and surgical techniques have evolved, there has been much progress made in improving survival for this unique group of patients, with 5-year survival approaching 55% with R0 resection (2). However, not all CRLM are the same, with very different biological behaviour and ultimately oncologic outcomes in different patients.