Paul Basilio, MDLinx | July 24, 2017
A new study from the Perelman School of Medicine at the University of Pennsylvania debunks the common practice of foregoing antiperspirant while receiving radiation therapy for breast cancer. The findings were published in Radiotherapy and Oncology.
Women who are undergoing daily radiation therapy for breast cancer are often told by their physicians to avoid applying antiperspirant out of a concern that it could cause greater radiation damage to the skin, but Penn researchers have found the suggestion is not grounded in sound science.
The study showed that about 8 in 10 patients reported their doctors told them to avoid antiperspirant during treatment, and roughly the same number of doctors claim to make that recommendation as well.
“Going without antiperspirants entirely for a 3-6 week course of radiotherapy can have a negative impact on a patient’s quality-of-life,” said the study’s lead author Brian C. Baumann, MD, who recently completed his residency in Radiation Oncology at Penn and is a member of Penn’s Leonard Davis Institute of Health Economics. “Our study suggests that antiperspirants can be safely used during breast radiotherapy without risking increased skin side effects.”
The study had two key areas: first, it established that it’s still common practice for physicians to advise breast cancer patients to avoid antiperspirants during radiotherapy. Second, it debunked the myth that the use of these antiperspirants increases the amount of radiation the skin receives, thus causing more damage to the skin.
Oncolink, an online cancer service dedication to patient and provider education, was used for the first part of the study. It is run by Penn’s Radiation Oncology unit.
Researchers developed a survey to assess the percentage of providers who still advise against antiperspirant use during radiation, as well as the percentage of patients who received that advice.
Of the 105 doctors and nurses who responded and who regularly manage radiation dermatitis for their patients, 86 (82%) said they regularly tell patients not to use antiperspirants during their course of radiation treatment. Of the 92 patients who responded, 73 (79%) say their healthcare providers advised them to avoid using antiperspirant for the duration of their treatment.
“While the sample size of the survey is relatively small, the percentage of patients who received the advice to avoid antiperspirants and the percentage of providers who routinely offer this advice was very similar,” said Dr. Baumann, who is currently an Assistant Professor of Radiation Oncology at Washington University in St. Louis. “We cannot make any conclusions about the exact prevalence of this recommendation, but we think the results strongly suggest that the recommendation remains popular.”
The prescription persists despite a lack of scientific evidence. Clinical trials have not shown an increase in skin side effects as a result of antiperspirant use, but this does not appear to have had an effect on clinical practice. Dr. Baumann says this shows that providers either do not know about these studies or they are skeptical of the results.
“There can be a discrepancy between the ways we measure skin toxicity in clinical trials versus the problems patients report to their healthcare providers,” he said. “The current skin toxicity scoring system has important limitations. It does not take pain or itching into account, for example, so it is possible that the studies may have missed a clinically meaningful effect because of the limitations of the measurement tool.”
To address that discrepancy, researchers sought to find whether antiperspirants actually do increase the surface dose of radiation on the skin with the use of optically stimulated luminescent dosimeters (OSLDs)–a common device for measuring the amount of surface radiation absorbed with each dose.
Three squares of paper were used. One square had nothing on it, one square had a thick coating of standard antiperspirant, and one had a thick coating of extra-strength antiperspirant. The squares of paper were placed in the beam’s path, and the OSLDs measured the absorbed radiation dose.
“We found no significant difference in surface dose with or without antiperspirant,” Dr. Baumann said.
His team also moved the beam to four different angles, but results were the same.
The antiperspirants in the study contained aluminum zirconium tetrachlorohydrex glycine, a common metal found in underarm products. The standard antiperspirant contained 15% of the metal, while the extra strength product had 25%.
“We specifically wanted to know if the radiation could hit that metal and scatter, sending radiation off target and into other, healthy parts of the skin, but any difference in surface dose we found was within the margin of error,” Dr. Baumann said. “This study shows providers should be more liberal in letting patients use antiperspirants during radiation treatment, which may improve patient quality-of-life.”