EDINBURGH – Patients with moles had more than four times the risk of developing melanoma, compared with those without moles in a large record-linkage study.
The overall rate ratio for melanoma, based on person-years at risk, was 4.68 among patients with moles recorded in their medical record (95% confidence interval, 4.39-4.98), Dr. Eugene Ong reported at the 15th World Congress on Cancers of the Skin.
Rate ratios were also significantly higher for individuals with moles of both sexes and in all age groups, including those aged younger than 25 years (RR, 3.79), 25-59 years (RR, 5.02), and at least 60 years (RR, 4.68).
Prior research has shown that high numbers of melanocytic or dysplastic nevi are strong risk factors for the development of melanoma. The investigators sought to further characterize the risk of melanoma in persons with melanocytic nevus (MN) using linked hospital and mortality records covering the entire population of England from 1999 to 2011.
The analysis included 271,656 patients with a hospital or day-case record of moles and a control cohort of 10,130,417 persons with no moles recorded. Anyone diagnosed with melanoma within 1 year of study entry was excluded.
Patients with a record of moles had a significantly higher risk of developing melanoma both around the site of the mole and elsewhere on their body, and therefore may benefit from increased surveillance, said Dr. Ong of the University of Oxford, England. For patients with a mole on the trunk, the rate ratio for a melanoma on the trunk was 8.99 (95% CI, 7.69-10.46) and 5.66 for a melanoma elsewhere (95% CI, 4.97-6.42).
The investigators were unable to distinguish between different types of moles or to determine the number of moles in each patient. Further, a mole or moles were the principal reason for hospital contact for 91% of patients, so it’s likely they presented with unusual appearing moles in order for them to warrant recording, Dr. Ong acknowledged.
“So while this study does not suggest that everyone with a single mole is far more likely to develop melanoma, it does illustrate the link between moles and skin cancer. This is why it is vital people check their moles regularly and report any changes to their doctor,” he said in a statement released during the meeting, sponsored in part by the Skin Cancer Foundation.