Breast cancer among older women: The influence of age and cancer stage on survival

Abstract

Purpose of study: To describe the association between increasing age and survival among women aged over 65 years, diagnosed with breast cancer.

Materials and methods: A historical prospective cohort study, comparing 3270 breast cancer patients to 13,163 non cancer age matched controls. Baseline characteristics and cancer data gathered from the Israeli Central Bureau of Statistics (1995), the Israel Cancer Registry (2000-2010). Baseline measurements included age, socioeconomic status. Cancer stage at diagnosis was clustered as stage I, stage II-III and metastatic. Cox Proportional Hazards regression models were used to determine Hazards Ratios (HR) for mortality.

Results: Between ages 65-69 and ≥85, metastatic disease rose from 3.9% to 23.4% and stage I disease declined from 58.6% to 30.1%. At age 80-84, 50% life expectancy among controls, stage I, and stage II-III disease was 95,92 and 90 months respectively, compared to 2 months for metastatic disease. Compared to controls, between the age 65-69 to ≥85, adjusted HR's progressively decreased among subjects with stage I from HR 0.96 (95% CI 0.69-1.33) to 0.60 (95%CI 0.36-1.01), stage II-III from HR 3.26 (95%CI2.58-4.12) to HR 1.60 (95%CI 1.22-2.09), and metastatic disease from HR 57.40 (95%CI 39.56-83.29) to HR 20.76 (95%CI 14.73-29.24).

Conclusions: This study describes the increasingly poor prognosis and short life expectancy observed among women aged ≥80 diagnosed with metastatic breast. In contrast, our findings confirm the positive prognosis associated with rising age, among older women presenting with stage I breast cancer, among whom survival was similar, if not slightly better, than non-cancer age matched controls.

Keywords: Breast cancer; Geriatric assessment; Palliative care; Survival.