Menopause
Hot flush treatment has anti-breast cancer activity, research finds

Megestrol, a hot flush drug for breast cancer patients, may also curb tumours when added to standard hormone therapy, an early trial has found.
The PIONEER trial tested megestrol acetate, a synthetic form of progesterone, alongside anti-oestrogen treatment in post-menopausal women with ER-positive breast cancer.
After two weeks, patients on the combination saw greater falls in tumour growth rates than those on anti-oestrogen therapy alone.
Dr Richard Baird from the University of Cambridge, who led the trial, said: “On the whole, anti-oestrogens are very good treatments compared to some chemotherapies.
“They’re gentler and are well tolerated, so patients often take them for many years. But some patients experience side effects that affect their quality of life.
“If you’re taking something long term, even seemingly relatively minor side effects can have a big impact.”
Around three-quarters of breast cancers are ER-positive, meaning tumours have high levels of oestrogen receptors and grow in response to the hormone.
Patients are typically offered anti-oestrogen drugs to reduce oestrogen levels and slow growth. However, these can trigger menopause-like symptoms including hot flushes, joint and muscle pain, and potential bone loss.
Low-dose megestrol has already been shown to ease these side effects, helping patients continue treatment. The Cambridge-led trial suggests it may also improve the treatment’s effect against the cancer itself.
The trial recruited 198 patients at ten UK hospitals, randomised into three groups: one receiving only the anti-oestrogen letrozole; one receiving letrozole with 40mg daily megestrol; and one receiving letrozole with 160mg daily megestrol.
Both megestrol doses showed comparable effects in boosting letrozole’s ability to block tumour growth.
Laboratory work by professor Jason Carroll and colleagues showed that progesterone stops ER-positive cancer cells dividing by indirectly blocking the oestrogen receptor.
Professor Carroll said: “These were very promising lab-based results, but we needed to show that this was also the case in patients.
“There’s been concern that taking hormone replacement therapy – which primarily consists of oestrogen and synthetic versions of progesterone (called progestins) – might encourage tumour growth.
“Although we no longer think this is the case, there’s still been residual concern around the use of progesterone and progestins in breast cancer.”
Dr Rebecca Burrell, joint first author, said: “In the two-week window that we looked at, adding a progestin made the anti-oestrogen treatment more effective at slowing tumour growth.
“What was particularly pleasing to see was that even the lower dose had the desired effect.
“Although the higher dose of progesterone is licenced as an anti-cancer treatment, over the long term it can have side effects including weight gain and high blood pressure.
“But just a quarter of the dose was as effective, and this would come with fewer side effects.
“We know from previous trials that a low dose of progesterone is effective at treating hot flushes for patients on anti-oestrogen therapy.
“This could reduce the likelihood of patients stopping their medication, and so help improve breast cancer outcomes. Megestrol – the drug we used – is off-patent, making it a cost-effective option.”
Further studies will be needed to confirm whether the drug has the same beneficial effects over longer treatment periods.
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