People with the most dangerous type of skin cancer tend to stay out of the sun and wear extra sunscreen the year after being diagnosed. But a new small study suggests those precautions don't last.
Two to three years after being diagnosed with melanoma, people spent as many days in the sun and were exposed to at least as much UV radiation as their peers without the disease, researchers found.
"Something tells us that they relax more when time passes by after diagnosis," Dr. Luise Idorn, the study's lead author from Bispebjerg Hospital in Copenhagen, Denmark, said.
"We think they just regress back to old habits."
Rates of melanoma have been rising in the United States, according to the American Cancer Society. It predicts over 76,000 new melanomas will be diagnosed in 2013.
People who have had melanoma have a higher than average chance of getting it again. But that risk can be reduced if they cover up and stay out of the sun, Idorn told Reuters Health.
To see how well patients protect themselves, she and her colleagues tracked 20 people during the three summers after they were diagnosed with melanoma.
They compared those patients to another 20 melanoma-free people who mirrored the patients in their age, gender and skin type.
All study participants recorded the time they spent in the sun and use of sunscreen in daily diaries. They also wore watches that measured UV radiation exposure.
During the first summer after patients were diagnosed with melanoma, they spent fewer days in the sun without sunscreen than people in the comparison group, the researchers found.
However, patients' daily UV radiation dose rose by 25 percent from the first summer to the second, and increased again in the third summer. People without melanoma, on the other hand, were exposed to similar levels of radiation across all three years.
UV exposure tended to be higher among patients than people without skin cancer by the third summer. But that difference was small and could have been due to chance, Idorn and her colleagues reported Wednesday in JAMA Dermatology.
Half of the cancer-free group and 60 percent of people with melanoma reported getting sunburned at least once during the study period, they added.
"I would have thought that a diagnosis of melanoma would change their behavior. This study indicates they may be more cautious, but only the first year after diagnosis," Idorn said.
"It's disturbing results that these patients who are really at quite high risk of a second melanoma are not reducing their sun exposure," Brenda Cartmel, from the Yale School of Public Health in New Haven, Connecticut, said.
"This is surprising," added Cartmel, who has studied people's behavior after a skin cancer diagnosis but wasn't involved in the new study.
The researchers noted that their study was small and did not include information on sun exposure from before participants developed melanoma.
"It may be more difficult than we realize for people who really enjoy the sun to stay out of it," Idorn said. "It may be a habit or a way of living that is difficult to abstain from, even after a cancer diagnosis."
Dermatologist Dr. Brundha Balaraman from Washington University School of Medicine in St. Louis said she found the results "not entirely surprising" because skin cancer is more common among people who spend lots of time in the sun to begin with.
"It would be interesting to assess sun behaviors before and after the diagnosis of melanoma to determine whether a patient improves from his personal baseline," Balaraman, who also didn't participate in the new research, said in an email.
According to Idorn, there's a need for more studies, including focus groups of people with melanoma, to figure out how doctors can help patients reduce their time in the sun.
Cartmel said she and her colleagues are working on those types of studies now.
"I don't think what we are going to advise people to do is going to be different," she said. "I just think somehow we need to get that message over maybe in a different way."