ORLANDO, FL—A single shot of medroxyprogesterone acetate (MPA) may offer a safe, effective alternative to daily venlafaxine for combating hot flashes, a randomized trial shows.
Reporting here at the ASCO Annual Meeting, Charles J. Loprinzi, MD, a medical oncologist at the Mayo Clinic, explained that previous studies have shown that both venlafaxine and progestins can help to alleviate hot flashes—“a big problem for women, especially breast cancer survivors. But many physicians are afraid to give women, especially those with breast cancer, hormonal treatments.”
So the researchers decided to pit the treatments against the other, randomly assigning 198 women who suffered from severe hot flashes to a single injection of 400 mg of MPA or to 37.5 mg/day of oral venlafaxine for one week, followed by 75 mg daily.
To qualify for the study, women had to have hot flashes at least two times a day on average for at least a month. Ninety percent of the women had hot flashes four or more times a day, and about one third had hot flashes at least 10 times a day. Two thirds of the women had a history of breast cancer.
Six weeks after therapy began, about 60% of the 94 women on venlafaxine were having fewer hot flashes than at baseline. But 80% of the 94 women who had a shot of MPA reported relief.
“Another way to put it is that if you look at these women six weeks later, only 1% of women on venlafaxine had no flashes, compared with 24% of those who used MPA,” Dr. Loprinzi said. “This was highly significant.”
And six months later, when the researchers contacted a “little less than half the patients, 10% of those in the venlafaxine arm still had less than 10% of the hot flashes they had at baseline versus 27% of patients in the MPA group,” he said.
There were no major side effects among women in the study. Those taking MPA had less trouble sleeping, less constipation, and less abnormal sweating than those on venlafaxine. Women on venlafaxine, on the other hand, experienced less stress and tension, as might be expected with an antidepressant, he said.
Expert Debate Hormone Use
“The $64,000 question is whether MPA,” a synthetic form of the hormone progesterone, “is safe to give in terms of breast cancer risk,” Dr. Loprinzi said. “There's really no proof one way or the other.”
Since women in the study received just one injection, “we think any risk is so small that this is a reasonable option to consider,” he said.
If hot flashes return over time, oncologists and their patients will have to decide whether the benefits of repeat injections outweigh any possible risks based on each woman's individual history, he said.
But other oncologists disagreed about whether they would use a progestin to treat hot flashes.
Leilani Morales, MD, of the Multidisciplinary Breast Unit at University Hospital Gasthuisberg in Leuven, Belgium, said that even if MPA is slightly more effective, she's still wary of a possible risk of breast cancer.
“I'd opt for a nonhormonal medication,” she said.
But William J. Gradishar, MD, Associate Professor of Medicine at Feinberg School of Medicine at Northwestern University and Director of Breast Oncology at Northwestern Memorial Hospital, said that “while it's generally good to avoid hormones, we have to keep in mind that progesterones are actually used to treat advanced breast cancer.”
The big question, he said, is whether patients would choose an injection—even if it's just once—over an oral medication. “In my experience patients prefer a pill. But if they suffer terrible hot flashes, a shot once a month may not seem so terrible.”
One way or another, the new information “is worth sharing with the individual patient as we discuss the risks and benefits of each treatment,” Dr. Gradishar said.
Black Cohosh Shows No Benefit
Also at the meeting, a separate study of 132 women showed that the herbal remedy black cohosh does not alleviate hot flashes.
Used extensively in Europe for this purpose, black cohosh (Cimicifuga racemosa) is derived from a plant that's a member of the buttercup family.
“There was no improvement of symptoms when women took black cohosh compared with placebo,” said surgeon Barbara Pockaj, MD, of the Mayo Clinic in Scottsdale, AZ.