SEATTLE — The impact of genetic testing on skin self-examination behavior among individuals at high risk for melanoma varies with personal history of the disease and test results, according to the first prospective study of this issue in a tested population.
Of 37 individuals at high risk for melanoma because of family history, those who had previously had the disease and who learned that they carried a mutation that sharply increased risk did not alter their skin self-exam behavior. Both before testing and 2 years afterward, 73% were doing these exams about every month, as is recommended, or more often.
Individuals who had not had melanoma but who learned that they carried the mutation stepped up their skin self-exam behavior: Only 30% were doing these exams at least monthly before testing, but 60% were doing so 2 years afterward.
By contrast, individuals who had not had melanoma and who learned that they did not carry the mutation had little change in their behavior, even though regular skin self-exams are also recommended for this group: 38% were doing these exams roughly once a month or more often before testing, and 44% were doing so at follow-up.
"Researchers and genetic counselors believe that learning one's objective risk will actually motivate behavior change," said lead investigator Jennifer M. Taber at the annual meeting of the Society of behavioral Medicine.
There are several concerns, however.
"One is that individuals who test negative will feel that their risk is so low that they don't need to engage in prevention or screening behaviors anymore, that they might feel a false sense of security and not change their behavior," she explained.
"Another concern is that for those who test positive, they will feel a sense of fatalism—that there is nothing they can do, their risk is so high anyway, so why bother engaging in the behaviors," she added.
Ms. Taber, a graduate student in psychology at the University of Utah in Salt Lake City, and her coinvestigators studied 37 adults from families with very high rates of melanoma. All underwent genetic testing for the p16 mutation, which sharply increases melanoma risk, and were followed for 2 years.
Nearly a third (30%) of participants were affected carriers, meaning they had a history of melanoma and had the mutation; 27% were unaffected carriers, meaning they did not have a history of the disease and did have the mutation; and 43% were noncarriers who did not have a history of the disease and did not have the mutation.
Monthly skin self-exams are recommended for all individuals from families with high rates of melanoma, regardless of their genetic test results, Ms. Taber noted, because even those with a negative result have a lifetime probability of the disease twice that of the general population.
The investigators classified the participants' skin self-exam behavior, according to the number of these exams performed in a 6-month period, as being on target (four to eight exams); overscreening (more than eight), which may actually hamper detection of changes; and underscreening (fewer than four), which may lead to missed lesions.
Two years after testing, the percentage of participants who were either on target or overscreening remained at the same high baseline level among affected carriers (73%) and had doubled among unaffected carriers (from 30% to 60%), but had increased only slightly among noncarriers (from 38% to 44%), Ms. Taber reported.
When the results were viewed another way, the percentage of participants who improved their skin self-exam practice during the 2-year period—to comply with the once-a-month recommendation—was 46% in the affected carrier group, 60% in the unaffected carrier group, and 25% in the noncarrier group.
Compared with participants who did not improve, those who did improve reported feeling that they had more control over detecting melanoma early (4.4 vs. 3.7 points on a 5-point scale).
In a subanalysis of the noncarriers, those who were underscreening at 2 years gave as their reason being busy or forgetful, feeling unqualified to perform the exams, and/or believing that their risk was not high enough.
In addition, noncarriers who improved their skin self-exam performance had a gain in their perceived control over early detection during follow-up, whereas those failing to improve did not.
The consistent finding of a link between an improvement in self-exam behavior and perceived control over detecting melanoma early has implications for strategies to increase this behavior, Ms. Taber said.
Perhaps physicians should target control perceptions over detecting a melanoma or perhaps skin self-examination competence, she commented.
Similarly, Ms. Taber noted, the barriers cited by noncarriers who were underscreening provide valuable insight specifically for individuals having negative genetic test results.