Adjuvant ovarian ablation versus CMF chemotherapy in premenopausal women with pathological stage II breast carcinoma: the Scottish trial. Scottish Cancer Trials Breast Group and ICRF Breast Unit, Guy's Hospital, London

Abstract

There are no previous reports of trials that have directly compared the effects of adjuvant chemotherapy with oophorectomy in premenopausal women with node-positive breast cancer. During 10 years we recruited 332 such women who were randomised, after mastectomy or conservation therapy, to receive either ovarian ablation or cyclophosphamide/methotrexate/5-fluorouracil (CMF) chemotherapy, each with or without prednisolone 7.5 mg daily for 5 years. After a maximum follow-up of 12 years, we detected no significant overall differences in relapse rates, or in event-free or total survival for ovarian ablation compared with chemotherapy or for prednisolone versus no prednisolone, nor any suggestion of an interaction between these factors. Actuarial total survival at 8 years was 60% overall, irrespective of treatment, with a hazard ratio and 95% Cl of 1.12 (0.76-1.63) for the comparison of CMF with ovarian ablation and 1.26 (0.86-1.84) for prednisolone versus no prednisolone. Oestrogen receptor (ER) assays were done in 270 (81%) primary tumours but these results played no part in the randomisation procedure. When patient outcome was analysed in relation to the concentration of ER in the tumour, there was a statistically significant interaction between ER content and treatment, such that ovarian ablation was associated with improved survival in patients with ER concentrations 20 fmols/mg protein or more and CMF was more beneficial for patients with values less than 20 fmols/mg protein. No such interaction was seen for prednisolone therapy. Oestrogen receptor content has a role in decisions about treatment for primary breast cancer.