Impact of Screening Mammography on Breast Cancer Outcomes in Women Aged 80 Years and Over

Abstract

Introduction: Age remains a significant risk factor for breast cancer, yet specific breast cancer screening guidelines for women > 75 years of age are not clearly defined. We sought to compare differences in outcomes among breast cancer patients diagnosed at ≥ 80 years of age based on receipt of screening mammography. Methods: This single-institution retrospective review identified breast cancer patients diagnosed at ≥ 80 years of age from 2013 to 2020. The screened cohort underwent screening mammography within 2 years of diagnosis. Characteristics of the screened/unscreened cohorts were compared using Chi-square and t-tests. Kaplan–Meier survival analysis and log-rank testing were performed to compare overall survival (OS) and disease-free survival (DFS). Cox proportional hazard models produced unadjusted/adjusted hazard ratios (HRs) to estimate the association of receiving a screening mammogram with OS/DFS. Results: Of 174 patients, 98 were screened and 76 were unscreened. Median age was 83 years, most patients had stage I/II tumors, and most cancers were estrogen receptor-positive/human epidermal growth factor receptor 2-negative. The groups did not significantly differ in race/ethnicity, comorbidities, receptor subtype, axillary surgery, or receipt of endocrine therapy/chemotherapy. Unscreened patients were more likely to have tumors that were palpable, high grade, and advanced stage. More screened patients underwent lumpectomy, while more unscreened patients omitted surgery. With a median follow-up of 55 months, the screened cohort had improved DFS (HR 0.45, 95% confidence interval [CI] 0.301–0.665; p < 0.001) and OS (HR 0.26, 95% CI 0.126–0.544; p < 0.001). This persisted when adjusted for age, receptor subtype, and surgery. Conclusions: Breast cancer patients diagnosed at ≥ 80 years of age who received screening mammography presented with earlier-stage disease and had improved DFS and OS compared with the unscreened cohort.