January 12, 2001

Hot flashes focus of cancer study

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Claudia Hazelwood, left, talks with Janet Carpenter, Ph.D., RN, about wearing the hot flash monitor. Women can easily carry the monitor with them during their daily activities. (Photo by Dana Johnson)

Hot flashes focus of cancer study

It’s a cruel twist of breast cancer treatment: the very drugs that may save a woman’s life may also cause severe hot flashes, and the risk of cancer recurrence rules out hormone replacement therapy for relief.

But an option could be in sight. A researcher in the Vanderbilt University School of Nursing has been awarded a $1.25 million, four-year grant to test a potential drug therapy for hot flashes induced by breast cancer treatment.

“About two-thirds of breast cancer survivors have hot flashes,” said Janet S. Carpenter, Ph.D., R.N., a member of the Vanderbilt-Ingram Cancer Center, assistant professor of Nursing and principal investigator. “About three-fourths of those women describe their hot flashes as severe, and almost half say they are extremely bothersome. In addition, about 50 percent of women report having daily hot flashes after breast cancer treatment.”

The study will test low-dose treatment, venlafaxine (Effexor), which at higher doses is prescribed as an antidepressant. Venlafaxine targets three biochemical pathways in the brain – norepinephrine, serotonin and dopamine – and it is the blocking of norepinephrine that the researches believe will affect the regulation of body temperature.

Carpenter explained that each person has a “null zone,” bounded on the high end by the temperature at which an individual begins to sweat and at the low end, the point where that person begins to shiver. Women who are prone to hot flashes appear to have a shallower null zone, she said. Levels of the stress hormone norepinephrine appear in animal studies to affect the size of the null zone.

Hot flashes occur in healthy women as a result of natural hormonal fluctuations that occur as the ovaries stop producing the female hormone estrogen. Pre-menopausal breast cancer survivors may be pushed into an artificial menopause by chemotherapy. In addition, many breast cancer survivors may also take an antiestrogen drug (tamoxifen or raloxifene) to prevent recurrence. These drugs also often cause hot flashes.

“Some women have dozens of hot flashes in a 24-hour period,” Carpenter said. “They can interfere with concentration and mood during the day and with sleep at night. Hot flashes after breast cancer treatment are often more severe than those experienced as part of natural menopause.

“For a long time, we have tended to ignore hot flashes in breast cancer survivors, but we’re now beginning to comprehend the impact on women, especially on their sleep and the fatigue associated with treatment.”

"For many patients, hot flashes are one of the most significant quality of life issues they must deal with," said Dr. David Johnson, deputy director of the Vanderbilt-Ingram Cancer Center. "Hot flashes disrupt daily activity, can interrupt sleep and may well be the source of many patients' feelings of extreme fatigue. These patients desperately need a safe and effective treatment that will provide relief."

One of the study participants, Claudia Hazelwood, 48, went into early menopause after her chemotherapy and radiation in 1999. However, when she began taking tamoxifen, she began to experience hot flashes that have interrupted her sleep and create anxiety in her work as a Vanderbilt University fund-raiser.

“I’ve struggled for about a year and it’s terrible,” Hazelwood said. “I’m not sleeping well. I’m in front of people a lot, and I worry about when I’m going to have one. Fortunately, I can control the temperature in my office myself, but I find I’m constantly turning the air conditioner on and off.”

Perhaps the hardest part, Hazelwood said, is that she was not prepared for the intensity of the hot flashes. “I thought I was through the worst of it with treatment, and then this hit me.”

The study will involve 100 women who are experiencing breast cancer treatment-induced hot flashes. Participants must be at least one month post-treatment for their first and only occurrence of breast cancer. They can be taking tamoxifen but must not be taking any medications for hot flashes or any other antidepressant.

The study is a “cross-over trial,” which means that each participant will receive treatment. Each participant takes six weeks of the drug and six weeks of placebo during the total 14-week participation period, but the order of treatment (drug-placebo or placebo-drug) varies. The study also includes recording a woman’s hot flashes during a 24-hour period each week with a special hot flash monitor that women can easily carry with them during their daily activities. Women will also be interviewed to assess mood and quality of life.

Participants will be required to make three trips to Vanderbilt for evaluation, but Carpenter and her colleagues will drive to participants’ homes or work sites to connect and disconnect the hot flash monitors. Therefore, participation is limited to women who live in Davidson and nine surrounding counties.

Women will receive $50 at their baseline hot flash monitoring and another $250 at the end of the study.

For more information, contact Carpenter via email at hot.flash@mcmail.vanderbilt.edu , via phone at 615-322-0831, or call the Vanderbilt-Ingram Cancer Center’s Cancer Information Program at 1-800-811-8480.