Evaluating safety of whole-body hormone replacement therapy in breast cancer survivors

This study aimed to investigate the safety and risk of disease recurrence in breast cancer survivors who were treated with systemic (whole-body) hormone replacement therapy (HRT). 

This study concluded that use of HRT increased the risk of disease recurrence in these patients.   

Some breast cancer (BC) treatments induce early menopause. Menopause is where a woman stops having menstrual cycles and is no longer able to get pregnant naturally. Natural menopause occurs at around the age of 51, usually after 45 years of age. It happens when the ovaries stop working and female sex hormones (such as estrogen and progesterone) drop to a very low level. In women with BC menopause can come very early due to the treatments for BC. 

The symptoms of treatment-induced menopause can negatively affect quality of life (QoL) and adherence to hormone therapy in BC survivors. HRT can be used in women with early menopause to alleviate thses symptoms. However, many BCs can grow in response to female sex hormones. Therefore, the use of HRT in BC survivors may lead to an increased risk of disease recurrence in these patients. The safety of HRT in BC survivors is still under investigation.  

This study involved data from previous trials that investigated the risk of disease recurrence with the use of HRT in BC survivors. This study analyzedd data from 4 trials involving 4,050 patients with BC. Of these patients, 2,022 patients received HRT in the form of estrogen/progesterone combination or tibolone (Livial). 2,023 patients were assigned to the control group that received a placebo or no HRT.  

HRT significantly increased the risk of BC recurrence by 46% compared to the placebo.  

The risk of BC recurrence with the use of HRT was significantly increased in patients with hormone-receptor-positive disease (by 80%). The risk of recurrence was also increased in those with hormone receptor-negative disease (by 19%), but this was not statistically significant. 

This study concluded that the use of HRT was associated with an increased risk of BC recurrence in BC survivors, particularly in those with hormone receptor-positive disease.  

This study did not differentiate among the different types of hormone therapy and treatment duration. Further studies are needed.