Rochester, MN—Women unable to use hormone replacement, including breast cancer survivors, have had few options for effectiveness treatment of hot flashes. Now, a new study suggests the drug oxybutynin can help reduce the frequency and intensity of the unpleasant menopause side effects.
Research was presented at the recent 2018 San Antonio Breast Cancer Symposium, held December 4-8.
Part of the problem is that hot flashes can be more severe in breast cancer survivors than in the general public, explained the study’s lead author, Roberto A. Leon-Ferre, MD, assistant professor of oncology at the Mayo Clinic. Leon-Ferre said that’s because:
• Chemotherapy might induce early menopause
• The use of antiestrogen medications, which are a major component of breast cancer treatment, can exacerbate the symptoms
• Hormone replacement therapy, which is sometimes prescribed to treat hot flashes, is generally not recommended for breast cancer survivors.
“Hot flashes not only impact quality of life; they can also be associated with premature discontinuation of breast cancer treatment, which may increase the risk of breast cancer recurrence and mortality,” he pointed out. “Therefore, it’s important to find effective options to treat hot flashes.”
Previous research has indicated that hot flashes may be relieved with oxybutynin, an anticholinergic agent that interferes with the activity of a neurotransmitter in the brain and in the peripheral nervous system. The drug is most commonly used to treat urinary incontinence.
Background information in a study conducted by Leon-Ferre and colleagues noted that hot flashes occur in about 75% of midlife women and are associated with quality-of-life disruption and premature endocrine therapy discontinuation among breast cancer survivors.
To examine oxybutynin as a possible treatment, a randomized, placebo-controlled trial enrolled women who had experienced hot flashes 28 or more times per week over more than 30 days. The symptoms had to be of sufficient severity to seek treatment.
Patients were randomized to receive oral oxybutynin at two doses: 2.5 mg twice a day for 6 weeks (Oxy2.5) or 2.5 mg twice a day for a week with subsequent increase to 5 mg twice a day (Oxy5), or matching placebo, in equal ratios.
Researchers administered baseline and monthly questionnaires, including a hot flashes diary, a related daily-interference scale (HFRDIS) and a symptom-experience questionnaire. The primary endpoint was improvement in both intensity and frequency.
The interim report includes the first 104 patients for which at least one postbaseline evaluation was available. Among those patients, 62% were on tamoxifen or an aromatase inhibitor for the duration of the study.
Results indicated that patients on both oxybutynin doses had a significantly greater reduction in HF score and frequency compared to placebo. Patients on Oxy2.5 had a mean change in HF score of -10 (SD 7.4) versus -5.1 (SD 9.7) with placebo, P = .003; and a mean change in average weekly number of HF of -4.6 (SD 3.1) versus -2.3 (SD 3.9), P = 0.002.
At the same time, patients on Oxy5 had a mean change in HF score of -16.2 (SD 5.1) versus -5.1 (SD 9.7) with placebo, P <.001; and a mean change in average weekly number of HF of -7.0 (SD 4.0) versus -2.3 (SD 3.9), P <.001.
The study team notes that HFRDIS revealed that patients in both oxybutynin arms experienced improvement in work, social activities, leisure activities, sleep, relations, life enjoyment, and overall quality of life. Patients on Oxy5 also had improvement in hot-flash interference with mood.
“This study, in addition to previously published work in this area, establishes that oxybutynin is an effective drug for treatment of hot flashes in patients who have relative or absolute contraindications to hormone-based therapy,” Leon-Ferre said. “We were surprised by the rapidity of the response and the magnitude of the effect, considering the relatively low dose of the drug.
“The fact that oxybutynin does not interfere with the metabolism of tamoxifen is an important consideration for breast cancer survivors, as some of the most effective non-hormonal treatments for hot flashes are thought to potentially decrease the efficacy of tamoxifen,” he added.
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Research was presented at the recent 2018 San Antonio Breast Cancer Symposium, held December 4-8.
Part of the problem is that hot flashes can be more severe in breast cancer survivors than in the general public, explained the study’s lead author, Roberto A. Leon-Ferre, MD, assistant professor of oncology at the Mayo Clinic. Leon-Ferre said that’s because:
• Chemotherapy might induce early menopause
• The use of antiestrogen medications, which are a major component of breast cancer treatment, can exacerbate the symptoms
• Hormone replacement therapy, which is sometimes prescribed to treat hot flashes, is generally not recommended for breast cancer survivors.
“Hot flashes not only impact quality of life; they can also be associated with premature discontinuation of breast cancer treatment, which may increase the risk of breast cancer recurrence and mortality,” he pointed out. “Therefore, it’s important to find effective options to treat hot flashes.”
Previous research has indicated that hot flashes may be relieved with oxybutynin, an anticholinergic agent that interferes with the activity of a neurotransmitter in the brain and in the peripheral nervous system. The drug is most commonly used to treat urinary incontinence.
Background information in a study conducted by Leon-Ferre and colleagues noted that hot flashes occur in about 75% of midlife women and are associated with quality-of-life disruption and premature endocrine therapy discontinuation among breast cancer survivors.
To examine oxybutynin as a possible treatment, a randomized, placebo-controlled trial enrolled women who had experienced hot flashes 28 or more times per week over more than 30 days. The symptoms had to be of sufficient severity to seek treatment.
Patients were randomized to receive oral oxybutynin at two doses: 2.5 mg twice a day for 6 weeks (Oxy2.5) or 2.5 mg twice a day for a week with subsequent increase to 5 mg twice a day (Oxy5), or matching placebo, in equal ratios.
Researchers administered baseline and monthly questionnaires, including a hot flashes diary, a related daily-interference scale (HFRDIS) and a symptom-experience questionnaire. The primary endpoint was improvement in both intensity and frequency.
The interim report includes the first 104 patients for which at least one postbaseline evaluation was available. Among those patients, 62% were on tamoxifen or an aromatase inhibitor for the duration of the study.
Results indicated that patients on both oxybutynin doses had a significantly greater reduction in HF score and frequency compared to placebo. Patients on Oxy2.5 had a mean change in HF score of -10 (SD 7.4) versus -5.1 (SD 9.7) with placebo, P = .003; and a mean change in average weekly number of HF of -4.6 (SD 3.1) versus -2.3 (SD 3.9), P = 0.002.
At the same time, patients on Oxy5 had a mean change in HF score of -16.2 (SD 5.1) versus -5.1 (SD 9.7) with placebo, P <.001; and a mean change in average weekly number of HF of -7.0 (SD 4.0) versus -2.3 (SD 3.9), P <.001.
The study team notes that HFRDIS revealed that patients in both oxybutynin arms experienced improvement in work, social activities, leisure activities, sleep, relations, life enjoyment, and overall quality of life. Patients on Oxy5 also had improvement in hot-flash interference with mood.
“This study, in addition to previously published work in this area, establishes that oxybutynin is an effective drug for treatment of hot flashes in patients who have relative or absolute contraindications to hormone-based therapy,” Leon-Ferre said. “We were surprised by the rapidity of the response and the magnitude of the effect, considering the relatively low dose of the drug.
“The fact that oxybutynin does not interfere with the metabolism of tamoxifen is an important consideration for breast cancer survivors, as some of the most effective non-hormonal treatments for hot flashes are thought to potentially decrease the efficacy of tamoxifen,” he added.
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