Incidence and Survival of Appendiceal Mucinous Neoplasms: A SEER Analysis

The aim of this study is to characterize the changes in the incidence, presentation, surgical treatment, and survival of patients with appendiceal mucinous neoplasm (AMN) over the past 4 decades using nationwide cancer surveillance data.

Patients with the diagnosis of AMN were identified in the Surveillance Epidemiology and End Results (SEER) database. Information on demographics, disease characteristics, and surgical treatment was collected. Temporal changes in AMN incidence, characteristics of cases, and survival were analyzed from 1973 to 2011. Determinants of overall survival (OS) were examined using both crude and multivariable Cox proportional hazard models.

The overall incidence rate of AMN increased on average 3.1%/1,000,000 persons-years (P<0.001). A significant decline in the age at diagnosis was observed (P=0.014). The proportion of patients presenting with distant disease at diagnosis also significantly increased (P=0.004). Five-year survival of patients with distant stage AMN increased at a rate of 3.5%/y between 1984 and 2006 (P<0.001). Median OS was not reached for localized and regional stage disease. Median OS for distant stage disease was 42 months.

There has been an increase in the overall incidence of AMN with an observed increase in the proportion of younger age and distant stage at diagnosis. The OS has improved over time.