Background: Currently, there are limited data on prognostic factors in metastatic colorectal cancer (mCRC) patients treated with chemotherapy. Prognostic factors in colorectal cancer remain varied in each situation when considering their use in different contexts.

Objective: To analyze the independent prognostic factors of mCRC in patients receiving chemotherapy.

Materials and Methods: Data from 156 mCRC patients completely treated by first-line chemotherapy were collected between 2013 and 2018. A retrospective observational cohort study was conducted to evaluate the survival analysis and prognostic factors. A univariate and multivariate Cox’s proportional-hazards model were used to explore and identify the independent prognostic factors for overall survival. An analysis of the restricted mean survival time (RMST) method was used to estimate the event-free time from zero to 24 months.

Results: Median overall survival was 18.3 months (96% CI 15.31 to 20.95). The multivariate Cox’s proportional-hazards model revealed two rognostic factors for decreased survival, poor Eastern Cooperative Oncology Group (ECOG) performance status greater than or equal to 2 (HR 2.05, 95% CI 1.08 to 3.86; p=0.027) and hypoalbuminemia lower than 3.5 g/dL (HR 3.47, 95% CI 2.10 to 5.75, p<0.001). Analysis of the RMST method was used to estimate the event-free time from zero to 24 months in the group receiving first-line oxaliplatin-based chemotherapy, secondline oxaliplatin-based chemotherapy, and second-line irinotecan-based chemotherapy. It was found that only the group receiving second-line oxaliplatin-based chemotherapy had significantly longer survival time than the comparison groups, with an adjusted mean of survival time of 21.12 months (different mean 5.99, 95% CI 3.99 to 8.00, p<0.001).

Conclusion: Poor ECOG performance status greater than or equal to 2, and hypoalbuminemia lower than 3.5 g/dL can be used as prognostic factors in mCRC patients receiving chemotherapy.

Keywords: Survival; Prognostic factors; Metastatic colorectal cancer; Chemotherapy

DOI: 10.35755/jmedassocthai.2023.01.13726

Received 17 May 2022 | Revised 20 October 2022 | Accepted 28 October 2022