Survival after Curative Resection for Stage I Colorectal Mucinous Adenocarcinoma

Abstract

Background: The prognostic value of the mucinous adenocarcinoma histotype on the early stages especially for stage I colorectal cancer (CRC) is still unclear. This study determined the clinicopathologic characteristics and long-term outcome of stage I colorectal mucinous adenocarcinomas (MAC). Methods: Among the total of 503 patients with stage I CRC (56 having MAC and 447 having non-MAC) who underwent radical resection, the correlation between clinicopathological factors and MAC was analyzed. Multivariate analysis was performed to determine whether mucinous histotype itself was an independent prognostic impact in stage I patients. Results: MACs were observed more frequently located in the colon than rectum (p=0.046), more frequently displayed the microsatellite instability (MSI) phenotype (p=0.023) and had a greater frequency of T2 stage (p=0.001). The rate of recurrence was 13.5% and the cancer-specific mortality was 4.3% among all stage I CRC patients. There was no difference in disease-free survival and overall survival between MACs and non-MACs. On multivariate analysis, older age (p=0.030，hazard ratio: 2.62), rectal cancer (p=0.025, hazard ratio: 5.42), lymphovascular invasion (LVI) (p<0.001, hazard ratio: 9.74), and microsatellite stability (MSS) phenotypes (p=0.023, hazard ratio: 4.21) were independently associated to poor survival of stage I CRC. A high carcinoembryonic antigen (CEA) level (p=0.031, hazard ratio: 1.95), rectal cancer (p=0.045, hazard ratio: 1.64), LVI (p=0.002, hazard ratio: 3.95) and MSS phenotypes (p=0.012, hazard ratio: 2.98) were independently related to short disease-free survival of stage I CRC.Conclusions: Compared with non-MAC, MAC patients had more T2 patients and more MSI phenotypes in stage I CRC at presentation, but the mucinous histology is not a significant predictor of recurrence and prognosis in stage I CRC.