Abstract 3744: Risk of esophageal and stomach malignancies in people with AIDS

Abstract

Abstract Introduction: The risks of infection related malignancies are strongly increased in people with HIV infection, especially for cancers where the infectious agent is directly associated with the tumor cells. H. pylori infection cause stomach cancer but is thought to be protective against esophageal cancer. Earlier studies have shown H. pylori only to be related to stomach cancers of the non-cardia and not the cardia anatomic site. Thus, we hypothesized that the rates of non-cardia compared to cardia stomach cancers in immune suppressed individuals will be most elevated. In this study, the risk of esophageal and stomach cancer was compared between people with AIDS and the general population by histological and anatomic sites. Methods: We utilized data from the HIV/AIDS Cancer Match Study, a linkage of 15 U.S. population-based HIV/AIDS and cancer registries during 1980-2007. To compare the risk of stomach and esophageal malignancies in people with AIDS to the general population, standardized incidence ratios (SIRs) were calculated by histological and anatomic sites. Associations with immune suppression were assessed by testing for trends in SIRs across AIDS relative time (60 months before AIDS diagnosis until 120 months after diagnosis) with Poisson regression. Results: During 1980-2007 among 597,073 people with AIDS, 915 stomach and 222 esophageal malignancies were registered. Overall for malignancies of the stomach and esophagus SIRs were 5.6 (95% confidence interval [CI] 5.2-6.0) and 2.3 (95% CI 2.0-2.6), respectively. At both sites, most of the increased risk was driven by excess of lymphomas. Compared to the general population, the risk of stomach adenocarcinoma was elevated in the non-cardia region of the stomach (SIR=1.6; 95% CI 1.2-1.9), but not in the cardia (SIR=1.1; 95% CI 0.8-1.6). Overall SIR for stomach non-mucosa-associated lymphoid tissue (MALT) lymphomas was close to eight times higher compared to MALT lymphomas (SIR=40; 95% CI 37-43, vs. SIR=5.5; 95% CI 3.5-8.2). When we examined SIRs across AIDS relative time we observed significant trends in SIRs with increasing time since AIDS for MALT (p-trend=0.02) and non-MALT lymphomas (p-trend<0.01), but not for the other histologies. For esophageal cancer increased SIRs were found: squamous cell carcinoma (1.5; 95% CI 1.2-1.8), adenocarcinoma (1.7; 95% CI 1.3-2.2) and lymphoma (123; 95% CI 94-158). An increased risk was also observed for squamous cell carcinoma of the abdominal/lower esophagus (SIR=1.7; 95% CI 1.1-2.5). Conclusion: Among people with AIDS the risks of stomach and esophageal malignancies are 6 and 2-fold higher than in the general population, respectively. Elevated risks for stomach adenocarcinoma in people with AIDS were limited to the non-cardia, the anatomic site that is most strongly associated with H. pylori infection. Further, risk of both stomach and esophageal lymphomas were especially elevated in people with AIDS. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3744. doi:10.1158/1538-7445.AM2011-3744