Patients with either familial or sporadic melanoma had a two- to three-times elevated risk for next melanoma based on the number of previous melanomas, with a notable risk in younger patients, according to recently published study results.
Researchers used the Swedish Family-Cancer Database of cancer cases retrieved from the Swedish Cancer Registry to identify 65,429 patients with invasive or in situ melanoma who received a diagnosis during the study period. There were 61,179 patients with sporadic melanoma and 4,250 patients with familial melanoma, and all patients were studied for next melanoma incidence.
The study’s main outcome measures were standardized incidence ratios (SIRs) expressing risk of next melanoma, for which the researchers calculated the incidence of next (second, third, fourth or fifth) melanoma in patients who had received a diagnosis of one, two, three or four previous melanomas compared with the risk of first melanoma in the Swedish population overall.
There was a stable two- to three-times elevated risk observed for patients with either familial or sporadic melanoma when numbers of previous melanomas were increased. The SIR for patients with a single previous melanoma was 2.5 (95% CI, 2.3-2.8) for familial melanoma and 2.3 (95% CI, 2.3-2.4) for patients with sporadic melanoma. The SIR for patients with four previous melanomas was 2.3 (95% CI, 1.3-3.9) for patients with familial melanoma and 2.7 (95% CI, 1.8-3.9) for patients with sporadic melanoma.
Patients with familial melanoma who received a diagnosis at younger than 40 years (SIR = 4.7; 95% CI, 3.6-4.6) had a higher overall risk of second melanoma. Young patients (aged < 40 years) with familial melanoma had a notable risk during the first 5-year follow-up after the first melanoma, with and SIR of 6.1 (95% CI, 4.0-9.0) for interval up to 1 year, and an SIR of 19 (95% CI, 10-31) for 4 to 5 years. The patients in the same age group with sporadic melanoma had notable risk within the first year of follow-up (SIR=5.3; 95% CI, 4.3-6.4), which remained steadily elevated afterward.
The researchers concluded it is possible younger patients have a distinct etiology, making it important for them to be referred for clinical genetic testing. – by Bruce Thiel
Disclosures: The researchers report no relevant financial disclosures.