Background: Malignancy of the appendix remains a rare phenomenon. There is little known about the socioeconomic disparities regarding survival amongst patients with appendiceal cancer. Hence, we investigated the differences in survival of appendiceal cancer across the racial groups. Methods: We performed a retrospective study of patients ≥18 years of age diagnosed with appendiceal cancer between 2007-2017 using data extracted from the United States Surveillance, Epidemiology, and End Results (SEER) database. Appendiceal cancer was classified as goblet cell carcinoid, mucinous adenocarcinoma, signet ring cell carcinoma, nonmucinous adenocarcinoma, and neuroendocrine tumor. Kaplan-Meier method was used to evaluate the cancer-specific survival for each racial group. We used the Cox proportional hazards regression to examine the association between mortality and patient characteristics. Effects were expressed as hazard ratios (HR) and 95% confidence intervals (CI). Results: A total of 6265 patients were identified; 4635 (74.0%) were White, 668 (10.7%) were Hispanic, 618 (9.9%) were Black, and 344 (5.5%) were Asian/Pacific Islander. The median age at the diagnosis was 57 years (Interquartile Range (IQR), 47-67), median follow-up was 32 months (IQR, 17-59 months). 3413 patients (54.2%) were female and 3771 (59.9%) were married. 5352 (85.0%) were insured. 5873 (93.3%) received surgery and 2136 (33.9%) received chemotherapy. 755 (12.0%) had goblet cell carcinoid, 2019 (32.1%) mucinous adenocarcinoma, 1126 (17.9%) nonmucinous adenocarcinoma, 442 (7.0%) signet ring cell carcinoma, and 1954 (31.0%) had neuroendocrine tumor. We found that Black patients had an increased risk of appendiceal cancer-specific mortality (HR=1.32; 95% CI 1.10-1.58). The mean appendiceal cancer-specific survival was highest amongst Whites with 92.91 months (95% CI 91.43-94.40) and the lowest amongst Blacks with 84.71 months (95% CI 80.16-89.25). Across all the patients, age, being uninsured, having Medicaid, higher stage at the time of diagnosis, receiving chemotherapy, goblet cell carcinoid, signet ring cell carcinoma, and nonmucinous adenocarcinoma subtypes were associated with a higher risk of appendiceal cancer-specific mortality. Conclusion: Significant racial disparity in appendiceal cancer-specific survival exists among appendiceal cancer SEER patients. Further research is needed to address the underlying cause of these disparities in order to improve outcomes.
Table: Bivariable and multivariable associations between patient characteristics and appendiceal cancer -specific mortality