Hormone medications can increase the risk of brain tumors, research shows
Millions of women around the world who take certain hormone drugs for birth control and to control conditions such as endometriosis may be at increased risk of rare, usually benign, brain tumors, researchers say.
Scientists found that long-term use of certain progestin medications was linked to a greater risk of meningioma, which are tumors (usually non-cancerous) that form in tissues around the brain.
But while the risk of meningioma was higher in women who took the drugs for more than a year, a leading expert said the finding should not worry past or current users as the increased risk remained “extremely small”.
Progestins are similar to the natural hormone progesterone. They are used in contraceptives, in gynecological conditions such as endometriosis and polycystic ovary syndrome, and in hormone replacement therapies used during menopause.
A handful of high-dose progestins is which is already known to increase the risk of meningioma, but in the latest study published in the BMJResearchers from the French National Agency for the Safety of Medicines and Health Products examined eight more commonly used forms of the hormone.
Most meningiomas are usually not cancerous and grow slowly, but because they can put pressure on the brain they often need to be removed surgically. The tumors are rarely life-threatening, but the surgery involved carries risks, not least to the brain structures near the tumors, which can sometimes be damaged.
Using data from the French national healthcare system, the researchers identified 18,061 women, with an average age of 58 years, who had undergone surgery to remove intracranial meningiomas between 2009 and 2018. By comparing each case with five healthy, matched controls, the researchers found that long-term use – that is, more than twelve months – of three progestins was associated with a greater risk of meningioma requiring surgery.
Two oral pills, medrogestone and promegestone, were associated with a 4.1- and 2.7-fold increased risk of meningioma, respectively; and medroxyprogesterone acetate, a birth control injection sold as Depo-Provera, was associated with a 5.6-fold increased risk. Because the study is observational, it cannot prove that the hormones cause the tumors. No excess risk was found for progesterone, dydrogesterone or commonly used hormonal intrauterine systems.
In a statement, Pfizer, the manufacturer of Depo-Porvera, said: “We are aware of this potential risk associated with long-term use of progestins and, in coordination with regulatory authorities, are updating product labels and patient information. leaflets with the correct wording.”
Writing in the journal, the researchers call for more research into the safety of the hormones, especially injectable medroxyprogesterone acetate. The shots are rarely used in Britain and the rest of Europe, but 74 million women worldwide receive them, meaning “the number of attributable meningiomas could potentially be high,” they write.
Prof. Paul Pharoah, a cancer epidemiologist who spent 20 years studying hormone-related cancers at the University of Cambridge before setting up a laboratory at Cedars-Sinai Hospital in California, said there were many different types of progestins and no link to meningioma was found. for those commonly used in Great Britain.
“Women who use commonly used birth control pills or hormone replacement therapy are not at increased risk of meningioma,” said Pharoah, who was not involved in the French study. “It is important that women do not stop taking their contraceptive pills without consulting their doctor.”
Based on UK cancer data registries, it is expected that around four in a thousand 30-year-old women will develop a meningioma by the age of 80. Taking medroxyprogesterone acetate for more than a year increases the risk by about fivefold, the BMJ study shows. suggests that this figure would rise to 20 per thousand.
“The risk of meningioma is extremely small,” Pharoah said. “If I were currently using Depo-Provera for the benefits of a long-acting injectable contraceptive, I would continue to do so. In short, current or former users of Depo-Provera do not have to worry about their very small risk of meningioma.”