Implementation of the prediction model is facilitated by an easy-to-use online calculator (https://paredespawlikcalc.shinyapps.io/CRLM/, accessed on 1 June 2022) that incorporates 11 prognostic variables: age, sex, primary tumor location, American Joint Committee on Cancer (AJCC) T stage, primary tumor lymph node metastasis, number of CRLM (>1), size of the largest tumor (>5 cm), CEA level >200 ng/mL, KRAS status (unknown, wild-type or mutated), disease-free interval <12 months and preoperative chemotherapy. The gene discussed is KRAS; the disease is neoplasm.