Prognostic Significance and Molecular Features of Colorectal Mucinous Adenocarcinomas: A Strobe-Compliant Study

Abstract

Mucinous adenocarcinoma (MC) is a special histology subtype of colorectal adenocarcinoma. The survival of MC is controversial and the prognostic biomarkers of MC remain unclear. To analyze prognostic significance and molecular features of colorectal MC. This study included 755,682 and 1001 colorectal cancer (CRC) patients from Surveillance, Epidemiology, and End Results program (SEER, 1973-2011), and Linköping Cancer (LC, 1972-2009) databases. We investigated independently the clinicopathological characteristics, survival, and variety of molecular features from these 2 databases. MC was found in 9.3% and 9.8% patients in SEER and LC, respectively. MC was more frequently localized in the right colon compared with nonmucinous adenocarcinoma (NMC) in both SEER (57.7% vs 37.2%, P < 0.001) and LC (46.9% vs 27.7%, P < 0.001). Colorectal MC patients had significantly worse cancer-specific survival (CSS) than NMC patients (SEER, P < 0.001; LC, P = 0.026), prominently in stage III (SEER, P < 0.001; LC, P = 0.023). The multivariate survival analysis showed that MC was independently related to poor prognosis in rectal cancer patients (SEER, hazard ratios [HR], 1.076; 95% confidence intervals [CI], 1.057-1.096; P < 0.001). In LC, the integrated analysis of genetic and epigenetic features showed that that strong expression of PINCH (HR, 3.954; 95% CI, 1.493-10.47; P = 0.013) and weak expression of RAD50 (HR 0.348, 95% CI, 0.106-1.192; P = 0.026) were significantly associated with poor CSS of colorectal MC patients. In conclusion, the colorectal MC patients had significantly worse CSS than NMC patients, prominently in stage III. MC was an independent prognostic factor associated with worse survival in rectal cancer patients. The PINCH and RAD50 were prognostic biomarkers for colorectal MC patients.

FIGURE 1

Survival differences between MC and NMC in (A) SEER and (B) LC. Colorectal MC patients had significantly worse cancer-specific survival than NMC patients. LC = Linköping Cancer, MC = mucinous adenocarcinoma, NMC = nonmucinous adenocarcinoma, SEER = Surveillance Epidemiology and End Results program.

FIGURE 2

The prognostic value of biomarkers in colorectal MC patients. The strong expression of PINCH (A) and weak expression of Rad 50 (B) were associated with poorer cancer-specific survival of colorectal MC patients. MC = mucinous adenocarcinoma.