Hypothesis: Patients who receive hormone replacement therapy (HRT) and subsequently develop breast cancer are more likely to be diagnosed by palpation than mammography and have a higher stage of cancer at initial diagnosis.
Design: Retrospective case series.
Setting: University hospital.
Patients: Two hundred ninety-two patients with breast cancer who were postmenopausal.
Interventions: Clinical examination, mammography, and definitive therapy.
Main outcome measures: Hormone replacement therapy use, mode of cancer detection, tumor size, nodal status, stage, and survival.
Results: Patients receiving HRT prior to diagnosis had significantly more incidences of mammographically detected tumors, ductal carcinoma in situ, T1 lesions, negative nodes, and better survival rates than nonusers.
Conclusions: A history of HRT use had only beneficial and no discernible adverse effects on breast cancer detection and outcomes. These effects of HRT seem to be due to the development of less aggressive tumors rather than earlier detection.