Thirty-year follow-up of chemo/hormonal therapy in node-positive breast cancer

Abstract

Results of a thirty-year follow-up of a clinical trial of chemo-hormonal therapy are reported. Eligible patients had recently diagnosed operable breast cancer, positive lymph nodes, no previous history of cancer, age less than 76 years, and no evidence of metastatic disease. A total of 311 patients were stratified by estrogen receptor (ER) status and number of axillary nodes involved with tumor. After stratification, patients were randomly assigned to one of three treatment regimens: cyclophosphamide, methotrexate and 5-fluorouracil (CMF) for 1 year; CMF chemotherapy combined with anti-estrogen therapy (tamoxifen) for 1 year; or CMF plus tamoxifen with BCG during the second year. The endpoint of the trial was a first recurrence. Factors measured at diagnosis and used in the analyses were age, body mass index, ER status, menopausal status, number of positive nodes, tumor diameter, Charlson comorbidity index, socioeconomic status, and race. Causes of death and incidence of other cancer primaries were obtained from death certificates and medical records. Patients treated with tamoxifen had a marginally longer disease-free survival (hazard ratio (HR)=0.83, 95% CI identical with [0.66, 1.04]) and statistically significant longer overall survival (HR=0.77, 95% CI identical with [0.63, 0.96]) that decreased with time. Incidence of other primary cancers and causes of death were similar for the two treatment groups. The addition of 1 year of tamoxifen to CMF therapy provides an early disease-free and overall survival advantage; however long-term effects are negligible. Similarly, the survival advantage of patients diagnosed with ER+ tumors persists for the first two decades after diagnosis.