Breast cancer in elderly women and altered clinico-pathological characteristics: a systematic review

Breast cancer is the most common malignancy in women in terms of incidence and mortality. Age is undoubtedly the biggest breast cancer risk factor. In this study we examined clinical, histological, and biological characteristics and mortality of breast cancer in elderly women along with their changes with advancing age. We reviewed 63 original articles published between 2006 and 2016 concerning women over 70 years with breast cancer. Compared to patients 70-79 years, patients aged 80 and over had larger tumor size with fewer T1 (42.9% vs 57.7%, p < 0.01) and more T2 lesions (43.5% vs 33.0%, p < 0.01). Lymph nodes and distant metastases were more frequent, with more N + (49.5% vs 44.0%, p < 0.01) and more M1 (8.0% vs 5.9%, p < 0.01). Infiltrating mucinous carcinomas were more frequent (4.3% vs 3.7%, p < 0.01). Tumors had lower grades, with more grade 1 (23.2% vs 19.8%, p = 0.01) and fewer grade 3 (21.5% vs 25.5%, p < 0.01), and were more hormone-sensitive: PR was more often expressed (72.6% vs 67.3%, p < 0.01). Lympho-vascular invasion was less frequent in the 80 years and over (22.9% vs 29.7%, p = 0.01). Breast cancer-specific mortality was higher both at 5 years (25.8% vs 17.2%, p < 0.01) and 10 years (32.7% vs 26.6%, p < 0.01). Clinico-pathological characteristics, increased incidence, and mortality associated with aging can be explained on one hand by biological changes of the breast such as increased estrogen sensitivity, epithelial cell alterations, immune senescence, and tumor microenvironment modifications. However, sociologic factors such as increased life expectancy, under-treatment, late diagnosis, and insufficient individual screening, are also involved.