The suspicion that hormone replacement therapy (HRT), a common treatment for menopause, may be related to an increase in the increased risk of developing ovarian cancer appears to be confirmed according to the data of a work published in ‘The Lancet’ and where 52 epidemiological studies of 21,488 women with ovarian cancer, almost all of North America, Europe and Australia has been reviewed.
The data indicate that women who have been on HRT for a few years have nearly 40% more likely to develop ovarian cancer than women who have never received HRT.
Although the use of HRT declined rapidly a decade ago, this decline has stabilized, and about 6 million women continue this treatment only in the UK and US. In addition, existing WHO guidelines in US and Europe on THS not mention ovarian cancer and previous studies have been too small to reliably assess the risks of their consumption over a short period of time.
The results showed that there was a significant increase in the risk of developing ovarian cancer in current or recent users (ie, women who took HRT for the past 5 years), and even though this risk decreased with time after stopping treatment, those who had used HRT for at least 5 years had a slightly increased risk of ovarian cancer 10 years later.
In addition, the researchers say the effect of HRT on the risk of developing ovarian cancer is the same for the two main types of hormone replacement therapy-therapies containing estrogen alone or combining estrogen and progestin. Also, the proportional increase in risk was not significantly affected by the age at which he began taking HRT, body size, prior use of oral contraceptives, hysterectomy, alcohol or family history of breast or ovarian cancer.
The study also found that of the 4 main types of existing ovarian cancer, increased risk was observed for the two most common types (serous and endometrioid ovarian cancers) only, and not for the two less common. The definite risk of ovarian cancer, even with consumption of less than 5 years of HRT, is directly related to current usage patterns – most women continue therapy for less than two years and has implications to review current guidelines.