Effect of age and comorbidity in postmenopausal breast cancer patients aged 55 years and older

Context: Postmenopausal women aged 55 years and older have 66% of incident breast tumors and experience 77% of breast cancer mortality, but other age-related health problems may affect tumor prognosis and treatment decisions. Objective: To document the comorbidity burden of postmenopausal breast cancer patients and evaluate its relationship with age on disease stage, treatment, and early mortality. Design and Setting: Data were collected on breast cancer patients' comorbidities by retrospective hospital medical records review and merged with information on patients' tumor characteristics collected from 6 regional National Cancer Institute Surveillance, Epidemiology, and End Results cancer registries. Patients were followed up until death or for 30 months from breast cancer diagnosis. Participants: Population-based random sample of 1800 postmenopausal breast cancer patients diagnosed in 1992 stratified by 3 age groups: 55 to 64 years, 65 to 74 years, and 75 years and older. Main Outcome Measures: Extent of disease, therapy received, comorbidity, cause of death, and survival. Results: Seventy-three percent (1312 of 1800) of the sample was diagnosed with stage I and II breast cancer, 10% (n=188) with stage III and IV breast cancer, and 17% (n=300) did not have a stage assignment. Of the 1017 patients with stage I and stage II node-negative breast cancer, 95% received therapy in agreement with the National Institutes of Health consensus statement recommendation for early-stage breast cancer. Patients in older age groups were less likely to receive therapy consistent with the consensus statement (P<.001), and women aged 70 years and older were significantly less likely to receive axillary lymph node dissection as determined by logistic regression analysis (P<.01). Diabetes, renal failure, stroke, liver disease, a previous malignant tumor, and smoking were significant in predicting early mortality in a statistical model that included age and disease stage. Breast cancer was the underlying cause of death for 135 decedents (51.3%). Heart disease (n=45, 17.1%) and previous cancers (n=22, 8.4%) were the next major underlying causes. In the 30-month follow-up period, 263 patients (15%) died. Conclusion: Patient care decisions occur in the context of breast cancer and other age-related conditions. Comorbidity in older patients may limit the ability to obtain prognostic information (ie, axillary lymph node dissection), tends to minimize treatment options (eg, breast-conserving therapy), and increases the risk of death from causes other than breast cancer.