Abstract 1834: Sex disparities in cancer mortality

Proceedings: AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010; Washington, DC INTRODUCTION: Previous research has noted that cancer mortality rates are higher for males than females, but no extensive analysis of this has been conducted. We wanted to study the extent of sex disparities in cancer mortality and if these disparities persist after adjustment for characteristics of the person and cancer. METHODS: We extracted U.S. vital statistics mortality data and cancer incidence and survival data from the SEER*Stat system for 36 cancers and undertook age-adjusted mortality rates and survival analyses. For the age-adjusted mortality rate analyses we extracted mortality count, person-years, and mortality rate per 100,000 for each cancer, stratified by sex and age for the period 1977-2006. Male-to-female mortality rate ratios (MRRs) were calculated. For each cancer, we plotted sex-specific mortality rates and male-to-female MRRs. For the survival analyses, we extracted patient id, age and date of diagnosis, sex, primary site, stage, grade, survival time, vital status and cause of death. Relative hazards for the 5-year period following diagnosis were estimated from Cox proportional hazard models adjusted for age, stage, grade, and year of diagnosis. RESULTS: For the vast majority of cancers, age-adjusted mortality rates were higher among males than females; the 5 cancers with the highest male-to-female MRR were lip (5.51, 95% confidence interval (CI):5.05-6.03), larynx (5.37, 95%CI:5.29-5.45), hypopharynx (4.47, 95%CI:4.30-4.65), esophagus (4.08, 95%CI:4.05-4.11) and urinary bladder (3.36, 95%CI:3.34-3.39). Only 3 cancers had a higher mortality rate among females than males: peritoneum, omentum and mesentery (MRR=0.39, 95%CI:0.38-0.41); gallbladder (0.56, 95%CI:0.55-0.57); and anus, anal canal and anorectum (0.78, 95%CI:0.75-0.81). The survival analyses indicated that males had a significantly increased risk of death, relative to females, for the cancers: anus, anal canal and anorectum (hazard ratio: 1.21, 95%CI:1.03-1.44); colon and rectum (1.08, 95%CI:1.07-1.09); floor of mouth (1.29, 95%CI:1.04-1.59); larynx (1.09, 95%CI:1.01-1.18); liver and intrahepatic bile duct (1.20, 95%CI:1.14-1.26); lung and bronchus (1.19, 95%CI:1.17-1.20); pancreas (1.06, 95%CI:1.03-1.08); small intestine (1.16, 95%CI:1.04-1.29); and soft tissue including heart (1.12, 95%CI:1.03-1.21). Females had higher mortality risks for the cancers tongue (0.87, 95%CI:0.81-0.94) and urinary bladder (0.83, 95%CI:0.81-0.86). DISCUSSION: Male cancer mortality rates were higher than equivalent female rates for the majority of cancers studied. Moreover, males also had higher risk of cancer mortality following diagnosis, relative to females, for many cancers even after adjustment for age of diagnosis, stage, grade and year of diagnosis. These observations indicate that there are sex differences in exposure and/or endogenous metabolic processes which modify risk of both cancer incidence and cancer mortality following diagnosis. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1834.