Luteinising-hormone-releasing hormone (LHRH) agonists, have proven effective when used alone or combined with existing treatments used in the fight against hormone receptor positive breast cancer, conclude authors of an Article published in this week's edition of The Lancet.
Luteinising hormone is produced in the pituitary gland and stimulates ovulation and the production of oestrogen. LHRH agonists are molecules which mimic the action of luteinising Hormone by binding to the same receptors within the pituitary gland and thereby block the signal for ovarian production of oestrogen, which is known to stimulate the growth of breast cancer.
Professor Jack Cuzick, Cancer Research UK Centre for Epidemiology, Mathematics and Statistics, Wolfson Institute of Preventive Medicine, Queen Mary's School of Medicine and Dentistry, University of London, UK and colleagues found that for hormone receptor-positive patients, LHRH agonists were as effective as chemotherapy treatment used in these trials.
Treatment with LHRH agonists combined with chemotherapy or tamoxifen gave an additional benefit, reducing recurrence of breast cancer by nearly 13% and death after recurrence by 15%. However the combined treatments only showed the additional benefit in women under 40. LHRH agonists were ineffective for hormone receptor-negative tumours.
The researchers did a meta-analysis (a study which combines results from previous trials) of 16 trials and obtained data for 11,906 premenopausal women with early breast cancer.
The authors conclude: "The results of our analysis show that LHRH agonists provide an effective additional class of agents for the treatment of premenopausal women with hormone-sensitive breast cancer."
In an accompanying Comment, Drs Nicholas Wilcken and Martin Stockler, Department of Medical Oncology, Westmead and Napean Hosptials and University of Sydney, NSW, Australia and NHMRC Clinical Trials Centre, University of Sydney and Sydney Cancer Centre, Royal Prince Alfred and Concord Hospitals, NSW, Australia, say: "In women with higher-risk disease, chemotherapy followed by tamoxifen should still be the standard approach, with the addition of an LHRH analogue a reasonable consideration for those who remain premenopausal.
"A century of research has taught us much about endocrine therapy for breast cancer, but the most important lessons about adjuvant ovarian suppression will be learnt over the next decade."