Breast Cancer Method of Detection: Screening Associated With Favorable Tumor Characteristics, Treatment, and Survival Across Age Groups.

Abstract

Objective: Breast cancer method of detection (MOD) describes how a cancer is first identified: through screening or nonscreening (symptomatic or 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 January 2019 and December 2021, with follow-up through July 2026. MOD was classified as screen-detected or non-screen-detected cancer. Logistic regression and χ² 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% versus 5.4%, P < .001), negative lymph nodes (N0: 85.5% versus 59.1%, P < .001), fewer metastases (M0: 98.6% versus 82.4%, P < .001), and lower grade (grade 1: 18.6% versus 7.4%, P < .001). More received lumpectomy (72.1% versus 50.2%, P < .001) and fewer received neoadjuvant chemotherapy (5.2% versus 22.5%, P < .001). Non-screen-detected cancers were more common among the unemployed (21.0% versus 14.0%, P = .001), uninsured (3.8% versus 1.7%, P = .026), and women ≥ 75 years (23.3% versus 16.1%, P = .019). Within non-screen-detected cancers, tumor stage worsened with time since last negative screen (P < .001). Screen-detected cancers showed superior all-cause survival (5-year survival: 92.9% versus 73.6%, P < .001). After adjustment, screen detection was independently associated with 43% lower mortality (hazard ratio = 0.57, P = .003). Significant survival benefit persisted in women ≥ 75 years (hazard ratio = 0.44, P = .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.