Purpose: Patients older than 80 years represent a significant breast cancer population but are underrepresented in clinical trials. It is established that estrogen receptor (ER)/progesterone receptor (PR)-negative status confers a worse prognosis in patients under 70, but this is not well studied in those over 80. We examined the prognosis of patients over 80 with ER/PR-negative disease to determine whether these patients are more likely to die of breast cancer than cardiovascular disease and to study treatment patterns.
Methods: We queried the Surveillance Epidemiology and End Results (SEER) database between 1992 and 2009 for patients with invasive breast carcinoma. Primary outcomes were breast cancer or cardiovascular death; secondary outcomes were radiotherapy and surgery. Cox proportional hazard analysis and logistic regression were used to determine adjusted outcomes over time. Subset analysis was performed comparing mortality rates by stage.
Results: There were 502,807 patients, 6,933 over 80 with ER/PR-negative disease. ER/PR-negative patients over 80 faced decreased 10-year survival compared to ER/PR-positive patients (61.5, 81.4 %; p < 0.05). ER/PR-negative patients were more likely to die of breast cancer than of cardiovascular disease (25.6, 12.2 %). Adjusting for confounders, ER/PR-negative patients over 80 were more likely to die from breast cancer specifically than patients aged 50-79 years [hazards ratio (HR) 1.53, 95 % confidence interval (CI) 1.43-1.64]. This finding was consistent across all stages. Compared to younger cohorts, elderly patients with ER/PR-negative disease received less radiotherapy [odds ratio (OR) 0.42, 95 % CI 0.39-0.46] and had a trend for less surgery (OR 0.86, 95 % CI 0.69-1.07).
Conclusions: Elderly ER/PR-negative patients are more likely to die of their breast disease than cardiovascular disease. Standard treatment regimens, especially radiotherapy, should be considered for elderly patients.