Patients With Melanoma Do Not Maintain Cautious Behavior About Limiting Exposure to UV Radiation From the Sun
Patients with cutaneous malignant melanoma “do not maintain the cautious sun behavior they exhibit just after … diagnosis,” even though they are at increased risk for developing a second primary melanoma, data from a Danish study suggested. Based on measurements obtained from personal electronic ultraviolet (UV) radiation dosimeters in a wristwatch, and a sun diary, the study found that patients’ daily doses of UV radiation increased 25% from the first to the second summer after diagnosis with cutaneous malignant melanoma. From the first to the third summer, the increase was 33%.
The study involved 21 patients with cutaneous malignant melanoma and 21 matched controls, with data analyzed for 40 patients. “After the second year of follow-up, patients’ UV [radiation] dose was higher than that of controls, who maintained a stable UV [radiation] dose,” Luise Winkel Idorn, MD, PhD, and colleagues from the University of Copenhagen reported in JAMA Dermatology. After looking separately at the 3 years of follow-up, the only statistically significant differences between patients and controls were that, compared to controls in the first year of follow-up, patients had fewer days with body exposure without using sunscreen (median, 1 vs 4 days, P = .003) and more days applying sunscreen on the upper extremities (median, 9.5 vs 0, P = .01).
Greater UV Radiation Exposure During Vacations Abroad
The dosimeters measure time-stamped UV radiation doses in standard erythema dose (SED) every fifth second and store a mean of the measurement every 5 minutes. The estimated increase for patients was 0.3 SED each year (P = .02). Looking just at days with body exposure, the estimated increase was 0.6 each year (P = .03) and at days on vacation or holidays, the estimated increase was 1.2 SED each year (P = .009).
The sun exposure diary included questions about exposing the shoulders or upper body outdoors, being on vacation or holiday (specifically abroad), and using sunscreen (and if so, what sun protection factor and on what areas of the body). “No difference was found between groups in the number of days with body exposure or the number of days using sunscreen in the second and third years of follow-up,” the investigators stated.
Patients spent more days abroad, with a mean of 7 days per person vs 3 days for controls, and more of those days, 53% vs 46% for controls, in sunnier climes than northern Europe (southern and eastern Europe, Africa, Asia, and South America). “This is disturbing because [cutaneous malignant melanoma] in general is believed to be caused by high intermittent UV [radiation] doses—a UV [radiation] exposure pattern that is associated with body exposure and holidays spent in sunny countries,” the authors noted.
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