Breast cancer tumor histopathology, stage at presentation, and treatment in the extremes of age

Abstract

Background Given presumed differences in disease severity between young (≤ 45 years) and elderly (≥ 75 years) women with breast cancer, we sought to compare tumor histopathology, stage at presentation, patterns of care, and survival at the extremes of age. Methods Adults with stages 0–IV breast cancer in the National Cancer Database (2004–2015) were categorized by age (18–45 years, 46–74 years, ≥ 75 years) and compared. Kaplan–Meier curves were used to visualize unadjusted overall survival (OS). A Cox proportional-hazards model was used to estimate the effect of age group, including adjustment for tumor subtype [hormone receptor [HR]+/HER2−, HER2+, triple-negative (TN)]. Results Of the 1,201,252 patients identified, 13% were ≤ 45 years and 17.5% were ≥ 75 years. Women ≤ 45 years were more likely to have higher pT/N stages and grade 3 disease compared to older patients; however, rates of de novo cM1 disease were comparable (3.7% vs 3.5%). HER2+ and TN tumors were more common in those ≤ 45 years (HER2+ : 18.6% vs 9.2%; TN: 14.9% vs 8.2%), while HR+/HER2− tumors were more likely in women ≥ 75 years (69.3% vs 51.3%) (all p < 0.001). Younger patients were more likely to undergo mastectomy vs lumpectomy (56% vs 34%), and receive chemotherapy (65.8% vs 10.2%) and radiation (56.2% vs 39.5%). After adjustment, OS was worse in older patients (older HR 2.94, CI 2.86–3.03). Conclusions High-risk tumor subtypes and comprehensive multimodal treatment remain significantly more common among younger women (≤ 45 years) with breast cancer, yet, elderly women are similarly diagnosed with incurable de novo metastatic disease. Tailored screening and treatment strategies are critical to prevent age-related disparities in breast cancer care.