Breast cancer screening in women aged 75 and older: Insights from an aging region in Japan.

Objective: In Japan, breast cancer incidence and mortality are rising with population aging. Screening may be associated with lower mortality but raises concern about overdiagnosis in older adults. Current guidelines provide no clear upper age limit. This study assessed screening in women aged ≥75 in an aging region. Methods: We retrospectively analyzed 289 women aged 75-98 years (median 81) diagnosed with breast cancer at Japan Red Cross Ishinomaki Hospital (2011-2020). Patients were classified as screened (population-based screening) or non-screened (symptom- or incidentally-detected). The primary outcome was all-cause mortality. Comparisons used Mann-Whitney U, chi-square, or Fisher's exact tests. Survival was analyzed by Kaplan-Meier and log-rank tests; prognostic factors by Cox models. Results: Of 289 patients, 46 (15.9 %) were screened and 243 (84.1 %) non-screened. Screened patients were younger, had smaller tumors, fewer lymph node metastases, and more surgery. Screening was associated with lower mortality in univariate but not multivariable analysis. No breast cancer-specific deaths occurred in the screened group versus 25 (10.3 %) in the non-screened group ( Conclusions: Screening was not an independent predictor of survival but was associated with absence of breast cancer-specific deaths, supporting further studies in elderly populations.