504P Prognostic factors of patients with AFP-positive colorectal cancer: A case-control study

Abstract Background: α-Fetoprotein-positive colorectal cancer (AFPP-CRC) is a rare type of colorectal cancer (CRC), and there have been no comprehensive investigations on prognostic factors of AFPP-CRC. The aim of this study was to elucidate the prognostic factors of AFPP-CRC. Method: During the years of 2010 to 2020, 127 CRC patients with preoperative elevated serum AFP level were collected, after excluding the diagnosis of hepatitis, hepatocirrhosis and hepatocarcinoma. The AFPP-CRC group was matched by 1:2 to the AFPN(α-Fetoprotein-negative)-CRC group after propensity score matching (PSM) analysis. Prognostic factors were investigated using univariate and multivariate Cox regression model. Kaplan-Meier curves were performed among the concerned prognostic factors as well. Logistic regression was used in studying associated factors between good and poor prognosis groups of AFPP-CRC. Result: After adjusting for other confounding factors by PSM, AFP positivity and tumor stage were shown to be associated with poorer disease-free survival (DFS). The median of overall survival (OS) was 26.4 months versus 30.3 months when comparing AFPP-CRC group versus AFPN-CRC group (P=0.09). The median of DFS was 23.3 months in the AFPP-CRC group, as compared to 26.0 months in the AFPNCRC group (HR:1.77, 95%CI:1.22-2.57, P=0.003). Among AFPP-CRC patients, those who also had poor prognosis were characterized by microsatellite stability even after considering other confounding factors (OR, 0.18; 95%CI, 0.04-0.63; P=0.01). Conclusion: We found higher serum AFP level before surgery was associated with worse DFS in patients with CRC, even adjusting for tumor stage. Besides, AFPP-CRC with microsatellite stability might had a worse prognosis.