Temporal trends and correlates of stage at diagnosis, receipt of treatment, and survival among men newly diagnosed with breast cancer in the United States.

Abstract

212 Background: Male breast cancer is rare, accounting for approximately 1% of all breast cancer diagnoses and 0.5% of all cancer diagnoses among men in the US. Despite its commonly delayed diagnosis and treatment and poor prognosis, existing research on male breast cancer has been limited by small sample sizes or older data. This study aimed to examine temporal trends and correlates of stage at diagnosis, treatment, and survival among men newly diagnosed with breast cancer in the US using two decades of nationwide cancer registry data. Methods: Men aged ≥18 years newly diagnosed with stages 0-IV breast cancer from 2004 to 2023 were identified from the National Cancer Database (n=26,969). We evaluated temporal trends in stage, timely treatment initiation ≤30 days, receipt of surgery, surgery type, and survival by 5-year interval. Logistic regressions and Cox proportional hazard models were used to examine the associations of key patient sociodemographic and treatment facility characteristics and each outcome. Results: Among men newly diagnosed with breast cancer, most were over 65 years (52.4%) and racialized as non-Hispanic White (77.7%). The stage distribution remained stable 2004 to 2023 (75.0% diagnosed with stages 0-II); however, the proportion initiating treatment ≤30 days declined substantially from 76% in 2004 to 36% in 2022, and five-year survival increased over time from 75.5% in 2004-2008 to 77.7% in 2019-2023 (adjusted Hazard ratio (aHR): 2019-2023 vs 2004-2008: 0.86 (0.78-0.95)). Sociodemographic and facility characteristics remained largely stable over time. Compared to men with private insurance, men with Medicaid (adjusted odds ratio (aOR) 0.65 (0.56–0.75)), Medicare and aged ≥65 years (aOR 0.56 (0.48–0.65)), Medicaid–Medicare dual eligibility (aOR 0.53 (0.47–0.60)) and without insurance (aOR 0.41 (0.35–0.48)) were less likely to have early-stage diagnosis (stages 0-II). Similarly, being without private health insurance was also associated with delayed treatment initiation and worse survival. Men treated at National Cancer Institute–designated facilities had lower odds of timely treatment initiation (aOR 0.57 (0.50-0.65)) yet had better survival (aHR: 0.86 (0.75-0.99)) compared with those treated at community facilities. Meanwhile, being racialized as non-Hispanic Black or Hispanic and residing in areas with higher poverty levels were also associated with later stage, delayed treatment, and worse survival outcomes. Conclusions: Health insurance coverage, sociodemographic characteristics, and facility type were associated with differences in diagnosis stage, care, and survival among men newly diagnosed with breast cancer. Targeted interventions to ensure access to high-quality care are important for this understudied population.