An individual’s clinical risk factors could help guide skin cancer screening and identify those at high risk for melanoma who could benefit from surveillance, according to a study published in JAMA Dermatology.
“Number of nevi, family history of melanoma, and a history of multiple primary melanomas are among the strongest risk factors for developing a first or subsequent melanoma,” wrote study authors led by Caroline G. Watts, MPH, of the University of Sydney in Australia. “Further characterization of individuals with these risk factors, and of the clinical features associated with their melanomas, may assist in the identification and treatment of this higher-risk subgroup and could improve our understanding of the etiological heterogeneity of melanoma.”
The researchers looked at 2,727 patients diagnosed with melanoma (in situ or invasive) from 2006 to 2007. Patients with higher-risk melanoma had a younger average age at diagnosis, were less likely to have a melanoma on their head or neck, and were less likely to have the lentigo maligna subtype compared with lower-risk patients.
Those in the high-risk melanoma group had an average age of 62 at diagnosis (compared with age 65 in the low-risk group; P < .001). Twenty-five percent of the higher-risk patients were younger than 50, compared with 16% in the lower-risk group. Prior studies have shown that onset at a younger age is associated with a genetic predisposition to melanoma.
Among higher-risk patients, 41% of patients with many nevi had melanoma on the trunk compared with 29% in the lower-risk group (P < .001). Those with a family history were more likely to have melanomas on the limbs (57% vs 42%; P < .001), and 21% of those with a personal history had melanoma on the head and neck compared with 15% in the lower-risk group (P = .003).
Both the higher- and lower-risk groups had similar proportions of men and women and both groups had similar socioeconomic distributions and proportions of patients from urban and rural areas.
Thirty-nine percent of the patients included were defined as higher-risk—those with a family history of melanoma, many moles, and a prior personal history of melanoma. Among patients with a higher melanoma risk, having many nevi (62%) was the most common risk factor followed by a personal history of skin cancer (42%) and a family history of melanoma (28%).
On average, the higher-risk patients had a higher proportion of superficial spreading melanomas than lower-risk patients (49% vs 45%), fewer lentigo maligna melanomas (12% vs 15%; P = .007), and a lower proportion of melanomas larger than 1 mm in thickness (29% vs 32%; P < .001).
A limitation of the study was the analysis of risk factors based on physician recall and patient medical records.
“Individuals at higher risk of developing melanoma are likely to benefit from increased surveillance including whole-body skin checks and monitoring of nevi,” the authors wrote. “The results of our study suggest that a person’s risk factor status might be used to tailor their surveillance program in terms of starting age and education about skin self-examination, or more intensive surveillance.”