Background: Prognostic biomarkers are increasingly important in the management of advanced colorectal cancer (ACRC). The aim of the present study was to evaluate the correlation of Kirsten rat sarcoma-2 virus oncogene (KRAS) mutation status with elevated carcinoembryonic antigen (CEA) levels in ACRC patients and their association with patients’ survival.
Methods: Patients with metastatic colorectal cancer were identified by a retrospective review of the Albany Medical Center cancer registry data from January 2006 to December 2014. Demographic, clinical, laboratory, and treatment data were retrieved after a manual review of patients’ electronic medical records. Only patients with complete data on CEA levels and KRAS mutation status were included in our analysis. Elevated CEA levels were defined as more than 3 ng/mL.
Results: Sixty-one patients with complete data were identified. Mean age was 58 years (SD 13.7, range 26-87), and 33 of them (54.1%) were male. In 23 out of 61 patients (37.7%), the rectum was involved. The pathologic diagnosis for all the patients was adenocarcinoma. Thirty-nine of 61 patients (63.9%) had wild-type KRAS (wKRAS) and 22 (36.1%) mutated KRAS (mKRAS). Out of 22 patients with mKRAS, 21 (95.5%) had elevated CEA levels prior to first treatment compared to 26 out of 39 (66.7%) with wKRAS (P = 0.011). The median CEA levels prior to treatment for patients with mKRAS was 57.5 ng/mL (IQR 12.6-79.8, range 1.8-16,512) compared to 7.8 ng/mL (2.13-17.7, 0.2-2,027; P = .037) in patients with wKRAS. Among patients with mKRAS and elevated CEA levels, the 1- and 5-year survival rates were 61.9% (13/21) and 0%, respectively, while the mean survival was 16.5 months (SD 10.6, range 1-42). The 1- and 5-year survival rates as well as mean survival for patients with wKRAS and elevated CEA levels were 84.6% (22/26), 3.8% (1/26), and 29.1 months (17.9, 8-84; P = .005) while for those with wKRAS and normal CEA levels were 91.7% (11/12), 25% (3/12), and 43.6 months (29.8, 1-108; P = .14), respectively.
Conclusion: Almost all ACRC patient with mKRAS have elevated CEA levels prior to first systemic therapy. ACRC patients with mKRAS and elevated CEA levels have lower survival rates.
