Appendiceal adenocarcinoma: Analysis of SEER database.

Abstract

e18097 Background: Appediceal cancers (AC) are rare, and often found on appendectomies. Adenocarcinomas represents approximately two-thirds of all AC. We performed the analysis of SEER database to understand the overall incidence and survival trends. Methods: We analyzed SEER database: Incidence - SEER 18 RegsResearch Data + Hurricane Katrina Impacted Louisiana Cases, Nov 2015 Sub (1973-2013 varying). Cases diagnosed of AC between 1988 and 2013 were identified. Trend of incidence rate was calculated. Relative survival rates (RSR) were calculated stratified by age, gender, race, stage, histological subtypes which were divided into mucinous, non-mucinous and signet ring cell carcinoma (SRCC). We calculated survival difference for patient diagnosed before and after 2000. Results: Age adjusted incidence rate of appendiceal adenocarcinoma was 0.4 cases per 100,000 person years. Overall incidence rate increased on average 3.7% per 100,000 person years (P < 0.05). The highest increase was seen in SRCC (4.8% per 100,000 person years). Survival was worst in SRCC (5 years RSR-28.40%) compared to other types (5 year RSR- 61.0% and 52.90% for mucinous and non-mucinous carcinoma (P < 0.01). Survival significantly improved for patients diagnosed after 2000 for mucinous (5 years RSR -51.90% and 64.30%) and SRCC (5 year RSR-18.0% and 31.0%), respectively before and after 2000 in each category. No improvement in survival was found in non-mucinous carcinomas since 2000. While survival among different histological types was not different for localized disease, it was significantly better for regional or distant stages in mucinous cancers when compared to non-mucinous cancers (P < 0.01). Elderly patient ( > 65 years) showed significantly poor survival for mucinous and non-mucinous carcinomas, while there was no variation in survival based on age for SRCC. Moreover, females showed significantly poor survival (P < 0.05) compared to males for SRCC, while no variation in survival based on gender for other types. Survival was not different among different races. Conclusions: Incidence of appendiceal adenocarcinomas is increasing. The highest increase is seen in SRCC which has the worst survival. Survival from mucinous adenocarcinomas has improved significantly in last decade.