Epidemiology and survival outcomes of mucinous adenocarcinomas: A SEER population-based study

To investigate the epidemiology, demographics and survival of mucinous adenocarcinomas (MACs), we identified 80,758 MAC patients in the Surveillance, Epidemiology and End Results (SEER) database. The reported incidence of MACs ebbed and flowed over time; however, a significant increase in reported annual age-adjusted incidences of MACs in the appendix, lung and bronchus was observed from 1981 to 2014. The demographics and outcomes of MACs differed by anatomic sites. MACs of the stomach had the largest percentage of poorly differentiated or undifferentiated tumors (41.2%), while MACs of the appendix and pancreas were associated with more advanced tumor stage (P < 0.001). MACs of the pancreas, lung and bronchus and stomach showed worse survival than other sites, despite localized, regional or distant stage (P < 0.001). In univariate and multivariate analysis, site, tumor grade, tumor stage, regional nodes, sex, race, surgery and year of diagnosis were identified as independent prognostic factors of cancer-specific survival. In conclusion, the incidence of MACs of certain specific sites, such as the appendix, lung and bronchus, is rapidly increasing. We also revealed a series of prognostic factors of MACs, including tumor sites, tumor grade and tumor stage, which may improve the current understanding of the clinical and biological patterns of MACs.