KRAS mutation is predictive of worse results after metastasectomy or adjuvant chemotherapy with hepatic arterial infusion (HAI) pump in the treatment of liver metastases in colorectal cancer patients. However, the KRAS mutation effect on tumor response in patients treated with HAI chemotherapy is unknown
Between March 18th and 19th, SSO 2021(International Conference on Surgical Cancer Care) took place in virtual format. At this event, a retrospective analysis was presented which investigated the effects of the KRAS mutation on tumor response in patients with unresectable colorectal liver metastases, treated with HAI pump chemotherapy. Maximal tumor response and objective response rate were assessed with computed tomography imaging; the objective response rate was defined as a cross-sectional decrease in target lesions by more than 50%.
Researchers reviewed cases from 25 patients with unresectable liver metastases from colorectal cancer who were treated with HAI chemotherapy between August 2017 and May 2019. The average age was 59 years and 13 (52%) were male. The median number of liver lesions was 12 and almost all patients (n = 24) underwent chemotherapy before starting HAI therapy. The median number of cycles administered through the HAI chemotherapy pump was equal to six.
The team observed an overall decrease in liver tumor burden of 63.5%, with an objective response rate of 80%, and 40% of patients converting to resectable status.
Eleven (44%) patients had KRAS mutation. When compared to the wild–type, mutated KRAS tumors had a lower response rate (7 of 11 [64%] versus 13 of 13 [100%]; P = 0.03) and response magnitude (median = 58% versus 70%; P = 0.04). There were fewer patients mutated KRAS tumors converted to resectable during HAI therapy (2 of 11 versus 8 of 13; P = 0.05).
Authors conclude that the KRAS gene mutational status in patients with colorectal cancer and the presence of unresectable liver metastases has a worse response to chemotherapy with HAI.