One study confirms that hormonal treatments for menopause have a low probability of developing breast cancer and that this risk increases with the duration of treatment.
A new study published on August 29, 2019 in the journal The Lancet confirms that women who are on menopausal hormone therapy (THM) are slightly more likely to develop breast cancer than others.
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An increased cancer risk of 2%
To reach this conclusion, the authors analyzed 58 epidemiological studies already published on the subject and bringing together a total of nearly 500,000 women. They were able to show that women aged 50 years under THM combining estrogen and progesterone for five years had a 8.3% risk of developing breast cancer within 20 years after the start of treatment. This risk falls to 6.3% for women of the same age without treatment and 6.8% for those following a THM containing only estrogen.
At first glance, one might think that it is better to use estrogen-only THMs than THMs that combine estrogen and progesterone. But it has already been shown that the administration of estrogen-only THM increases the risk of endometrial cancer. "For women who still have their uterus, it comes down to having to choose between the breasts or the uterus"summarizes Françoise Forette.
Ban long-term treatments
Moreover, what the researchers also observed is that the duration of prescription of the treatment played a role on the risk of breast cancer: "there is little risk after THM use for less than a year, but some increased risks with use from one to four years only and risks that increase gradually with the length of use"so write the researchers in their publication."Women who take THMs for less than one year are safe and those who take THMs for five years have a risk of about 2%, which remains low.", tempers Professor Forette.
Therefore, according to her, since "the risk is individual and we can not detect it, there is no reason to deprive women of menopausal treatment for a few months to a year".
The approach to be adopted would therefore be "no longer prescribe these very long-term treatments over a decade"but to continue to prescribe them for short periods of time to women who are very ill with menopause because they have"extraordinary effects on the quality of life"recalls the doctor.
Promote the cutaneous route
Another point to consider when prescribing: the mode of administration of THM. Because according to the findings of this study, the only hormone treatment that is not associated with an increased risk of cancer is the estrogen gel for local application to the vagina. "This type of treatment is therefore to be favored, and this also to reduce the risk of cardiovascular complications "supports Professor Forette.
In all cases, "prescribing gynecologists are extremely cautious in their prescription"remark the geriatrician.
A precautionary principle that may evaluate depending on the results of future work. Because even if this last study concerns a large number of women, it remains observational. In other words, it highlights an association but does not prove that there is a cause-and-effect relationship between breast cancer and hormonal treatment of menopause.