October 10, 2013 | by Roberta Nichols
Once burned, twice shy? It would seem that anyone who has been diagnosed with melanoma – the most deadly type of skin cancer – would be doubly cautious about their future exposures to the sun.
Not so, according to a new study in JAMA Dermatology, published online Oct. 2.
Because ultraviolet radiation (UVR) is the primary risk factor for developing cutaneous malignant melanoma (CMM), and CMM patients are at heightened risk of developing a second primary melanoma, researchers sought to shed light on the behavior of patients over a three-year period following diagnosis.
First author Luise Winkel Idorn, M.D., Ph.D., of Bispebjerg Hospital and the University of Copenhagen, Denmark, and her colleagues analyzed data from 40 participants, including 20 patients with CMM and 20 control subjects who did not have the disease but who were matched to patients by sex, age, occupation and skin type.
From May 7 to Sept. 22, 2009, April 17 to Sept. 15, 2010, and May 6 to July 31, 2011, researchers studied each participant an average of 74 days each year, measuring their exposure to UVR in two ways. Patients and control subjects wore wristwatches with electronic dosimeters that continuously monitored their sun doses, and they also kept diaries to document their number of exposures and sun protection measures.
"Our findings suggest that patients with CMM do not maintain a cautious sun behavior in connection with an increase in UVR exposure, especially on days with body exposure, when abroad, and on holidays," they continued.
Patients’ daily UVR dose increased 25 percent from the first to the second summer after diagnosis and 33 percent from the first to the third summer following diagnosis, according to a JAMA Dermatology press release.
"This study confirms a few other retrospective studies that had similar findings – that people with melanoma don’t change their long-term sun behavior," said Jae Jung, M.D., Ph.D., assistant professor of dermatology at City of Hope who was not involved in the research.
Though the study reflects patterns of behavior Jung has seen in some of her own patients, she suspects that a larger study might demonstrate differences in behavior based on age. "In my personal experience, younger patients will forget to sun protect but older patients are much more careful."
"I think the sample size is small and although they used objective devices to measure UVR, their overall assessment still includes a patient-reported sun diary," she said.
Like dieters keeping a food log who may not record every morsel eaten, those keeping track of sun exposures may not document every instance they stepped into the sunshine without slathering on sunscreen. "And the amount of sun that their skin is exposed to is not accurate since the UVR device cannot account for SPF or clothing," she added.
Still, Jung was impressed by the study's prospective design that allowed researchers to study changes in sun behavior within the same population for three consecutive summers.
She sees similarities between UVR overexposure and the obesity epidemic. "Everyone knows how to eat healthy and exercise – we just don’t do it – even patients who have had bariatric surgery," she said.
Sometimes skin cancer patients simply ignore warnings, like those with melanoma and a family history of the disease who continue to frequent indoor tanning booths.
Even some patients who conscientiously try to protect themselves from the sun are often unsuccessful due to their occupations (such as farming or construction work), hobbies (such as gardening, hiking or sports) or family obligations (such as kids’ soccer games), Jung said.
Jung always reinforces the importance of sun protection with all of her patients – especially those with skin cancer.
"This article just reinforces the fact that we need more effective tools to help our patients," she said. "The education and knowledge are there – the patients just aren’t doing it."
Learn more about skin cancer on our skin cancer information page.
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