Breast cancer; can longer-term hormone therapy improve outcomes?

The authors aimed to assess the benefits of prolonged use of hormone therapy to treat breast cancer in women undergoing the menopause transition.

Endocrine or hormone therapy is a type of treatment used to fight cancer cells with the presence of hormone receptors (HR+). Hormones natural to our body such as estrogen or progesterone can then aid cancer cell stimulation and growth.

Tamoxifen (Nolvadex)  is a type of hormone therapy that binds to the estrogen receptors (proteins on the cell surface that respond to estrogen hormone), preventing estrogen from binding to them, which could stimulate tumor growth. Other hormone therapies include letrozole (Femara) and exemastane (Aromasin). 

Previously, 5 years of hormone therapy has been the recommended length of treament. New studies, however, aim to evaluate the effects of prolonged use of hormone therapy, particularly in those who are peri-menopausal (going through the transition or having just transitioned to menopause). 

Several studies were conducted in search of these findings. The common aims were to evaluate the effect of the prolonged use of hormone therapy to treat women with HR+ breast cancer who may be undergoing the transition to menopause.

In one trial, 6,953 breast cancer patients who received tamoxifen for an extended period of 10 years altogether were evaluated. These patients were positive for estrogen receptor breast cancer (ER+; presence of estrogen hormone receptor proteins on cancer cells). These patients had a 25% decreased chance of developing recurrent cancer (the cancer returns). There was also a 23% reduced likelihood of death due to breast cancer. In another study of study of 12,894 ER+ breast cancer patients, patients had a 29% reduced likelihood of death due to breast cancer.

In a study of 5,170 patients who received 10 years of letrozole therapy, the risk of cancer returning was reduced by 42% while the risk of death from any cause was reduced by 18%. 

In another study of exemastane taken for 10 years in 1,589 patients, patients had a 32% reduced risk of the cancer returning. 

The authors concluded that the prolonged use of hormone therapy (10 years) was beneficial for women with breast cancer as the likelihood of recurrence and death due to the disease was decreased.

Further studies need to be carried out to provide a fully validated outcome of prolonged use of hormone therapy.

If you are currently receiving hormone therapy, discuss your future options with your doctor as you may be a suitable candidate to prolong your treatment.