72241 - Survival in Appendiceal adenocarcinoma in Sweden
Joel Johansson, Roland Andersson, Per Loftås, Stefan RedéenAbstract
Introduction
Appendiceal adenocarcinoma (AA) is a rare malignancy with increasing incidence that is associated with poor outcomes. Much of the existing knowledge is derived from registry-based studies, particularly the Surveillance, Epidemiology, and End Results (SEER) database in the US.
Method
This retrospective cohort study utilized data from the Swedish Cancer Registry, Swedish Cause of Death Registry and the National Patient Registry to analyse demographic characteristics and outcomes of AA patients diagnosed from 1970 to 2019. Kaplan-Meier survivor function, multivariable Cox regression analysis, standardized mortality ratio, relative survival and Poisson regression analysis was used to assess survival and factors that affect survival. Incidence was estimated by direct standardization and incidence rate ratio (IRR) from 2005 till 2019.
Result
A total of 2,436 AA patients were included, with a mean age at diagnosis of 64.2 years. Five-year survival improved over time. Increasing age and disease stage were associated with decreased survival, as well as not undergoing surgery or only exploration. Cytoreductive surgery with HIPEC and a mucinous histological subtypes were associated with improved survival. Seeking medical care for acute abdominal pain during the year prior to diagnosis did not affect mortality. Both in situ lesions and invasive AA increased from 2005 onwards. In situ lesions saw the largest increase (IRR 11,50 p<0,01).
Discussion
While survival increases over time excess mortality remains high and is increasing. Seeking medical care for acute abdominal pain during the year prior to diagnosis did not affect survival. This could have implications for conservative management of appendicitis.