Breast Cancer Method of Detection: Screening Associated with Favorable Tumor Characteristics, Treatment, and Survival Across Age Groups.
OBJECTIVE Breast cancer method of detection (MOD) describes how a cancer is first identified: through screening or non-screening (symptomatic/incidental) presentation. We examined associations between MOD and patient demographics, tumor characteristics, treatment patterns, and survival. METHODS This retrospective cohort study included women ≥40 years diagnosed with breast cancer between 1/2019 and 12/2021, follow-up through 7/2026. MOD was classified as screen-detected or non-screen-detected. Logistic regression and chi-square tests evaluated associations with patient, tumor, and treatment variables. Kaplan-Meier and multivariable Cox regression assessed all-cause survival. RESULTS Among 1,023 women (mean age 63.5 ± 12.1 years), screen-detected cancers (n=710, 69.4%) had more favorable characteristics: earlier T stage (T0: 26.3% vs. 5.4%, p<0.001), negative lymph nodes (N0: 85.5% vs. 59.1%, p<0.001), fewer metastases (M0: 98.6% vs. 82.4%, p<0.001), and lower grade (grade 1: 18.6% vs. 7.4%, p<0.001). More received lumpectomy (72.1% vs. 50.2%, p<0.001) and fewer received neoadjuvant chemotherapy (5.2% vs. 22.5%, p<0.001). Non-screen-detected cancers were more common among the unemployed (21.0% vs. 14.0%, p=0.001), uninsured (3.8% vs. 1.7%, p=0.026), and women ≥75 years (23.3% vs. 16.1%, p=0.019). Within non-screen-detected cancers, tumor stage worsened with time since last negative screen (p<0.001). Screen-detected cancers showed superior all-cause survival (5-year: 92.9% vs. 73.6%, p<0.001). After adjustment, screen-detection was independently associated with 43% lower mortality (HR=0.57, p=0.003). Significant survival benefit persisted in women ≥75 years (HR=0.44, p=0.014). DISCUSSION Screen-detected breast cancers were associated with favorable biology, less aggressive treatment, and improved survival. These findings can inform screening guidelines and underscore the importance of incorporating MOD into cancer registries.