endocrine therapy in breast cancer

Combined data from four randomised trials involving 314 women aged less than 35 years indicate that women with hormone receptor positive tumours who did not have endocrine therapy after their chemotherapy had significantly worse disease-free survival than women with hormone receptor negative tumours.15 For premenopausal women with hormone receptor positive cancers, endocrine therapy currently comprises tamoxifen, ovarian suppression or both. Ovarian suppression can be achieved through surgical, radiotherapeutic or chemical means, which should be discussed with the woman as appropriate. Ovarian ablation by surgery or irradiation has been shown to improve long-term survival in women aged younger than 50 years, particularly in the absence of chemotherapy.1 Luteinizing hormone-releasing hormone (LHRH) agonists such as goserelin are effective in suppressing ovarian function chemically; this effect is potentially reversible following cessation of treatment.120 More is known about tamoxifen, which significantly improves recurrence-free and overall survival in women of all age groups and is recommended for most women with oestrogen receptor positive tumours (Level I).116


Treatment with tamoxifen for five years reduces the risk of disease recurrence by up to half in premenopausal women with oestrogen receptor positive cancers.116 This relative reduction in risk will be translated into different absolute benefits depending on individual patient factors.


Ongoing clinical trials are examining whether treatment with tamoxifen for more than five years is beneficial. An average effect of tamoxifen alone in women less than 50 years old would be to improve 10-year disease-free survival from 80% to 85% (small node negative tumour) or from 55% to 65% (small node positive tumour).118 Ovarian suppression may have similar effects. Indeed, in two recently published trials temporary ovarian suppression with goserelin for two years was found to be as effective for disease-free survival as chemotherapy,121 and ovarian
suppression plus tamoxifen was more effective than chemotherapy.122