Abstract A136: Sex differences in cancer stage at diagnosis of non-reproductive solid organ tumors in the US, 2015-2019

Abstract Background: Men are more likely to die from cancer than women, which may partly be explained by differences in stage at diagnosis. This pan-cancer investigation aims to evaluate sex-based differences in the odds of being diagnosed at regional or distant stages versus localized stage for non-reproductive solid organ tumors. We hypothesize that, with few exceptions, men will have significantly greater odds of being diagnosed with cancer at later stages compared to women. Methods: We used data from the Surveillance, Epidemiology, and End Results (SEER) 22 database (2015-2019). We conducted multiple polytomous logistic regression to assess the association between sex and stage of disease (localized versus regional or distant) at the time of diagnosis for 40 cancer sites, adjusted for age, race and ethnicity, and year of diagnosis. Results: In a cohort of 1,883,742 cancer patients (56.7% male, 43.3% female), men had significantly higher odds of later-stage diagnosis for 23 cancer sites compared to women. The sites with the largest odds ratios (OR) include the tongue (regional stage: OR=2.49, 95% confidence interval (CI)=2.35, 2.62; distant stage: OR=2.48, 95%CI=2.26, 2.72); salivary gland (regional: OR=2.00, 95%CI=1.82, 2.19; distant: OR=2.14, 95%CI=1.89, 2.42); stomach (regional: OR=1.65, 95%CI=1.58, 1.72; distant: OR=1.53, 95%CI=1.47, 1.60); and thyroid (regional: OR=1.76, 95%CI=1.71, 1.81; distant: OR=2.50, 95%CI=2.33, 2.68). Conversely, men were significantly less likely to be diagnosed at the later stages for seven cancer sites, including the anus (regional: OR=0.89, 95%CI=0.83, 0.95; distant: OR=0.76, 95%CI=0.69, 0.85); peritoneum (regional: OR=0.32, 95%CI=0.22, 0.46; distant: OR=0.22, 95%CI=0.16, 0.30); larynx (regional: OR=0.59, 95%CI=0.55, 0.63; distant: OR=0.88, 95%CI=0.80, 0.97); and bladder (regional: OR=0.82, 95%CI=0.79, 0.86; distant: OR=0.71, 95%CI=0.68, 0.75). Conclusion: These findings underscore the importance of recognizing and addressing sex-based differences in cancer detection and diagnosis. For most cancer sites we examined, men were significantly more likely to be diagnosed at the regional or distant stages than the localized stage when compared to women. These results may be explained by differences in health care utilization; typical symptoms being based on one sex; and genetic and hormonal differences. Further investigation is warranted to elucidate the mechanisms driving sex-based differences in stage at diagnosis and to identify effective, targeted intervention strategies aimed at reducing diagnostic disparities. Citation Format: Beth J. Maclin, Meredith S. Shiels, Prema Bhattacharjee, Sarah S. Jackson. Sex differences in cancer stage at diagnosis of non-reproductive solid organ tumors in the US, 2015-2019 [abstract]. In: Proceedings of the 18th AACR Conference on the Science of Cancer Health Disparities; 2025 Sep 18-21; Baltimore, MD. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2025;34(9 Suppl):Abstract nr A136.