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Multiple primary melanomas most likely in first year after initial melanoma diagnosis

The risk for multiple primary melanomas was greatest in the first year after initial melanoma diagnosis, with patients who were older, male, white and partnered being at higher risk, according to recently published study results.

Researchers estimated multiple primary melanoma incidence among 16,570 Kaiser Permanente Northern California members diagnosed with melanoma between 1996 and 2011. Characteristics of patients with multiple primary melanomas and single primary melanomas were compared.

The cohort included 15,448 patients with single primary melanomas and 1,112 patients with multiple primary melanomas. In the multiple primary melanoma cohort, 172 patients developed a third melanoma and 64 patients had four or more subsequent primary melanomas.

Compared with patients with single primary melanomas, patients with multiple primary melanomas at initial melanoma diagnosis were more likely to be older (mean age, 64.4 years vs. 61 years), male (65.8% vs. 55.5%), non-Hispanic white (94.4% vs. 92.3%), and partnered (59.8% vs. 53.2%). A mean time of 3.38 years took place between time of diagnosis of initial primary melanoma and subsequent primary melanoma, 2.78 years between the second and third tumor and 2.15 years between the third and fourth tumor. Subsequent primary melanomas were more likely to be in situ and thinner, compared with the initial tumor.

There was a decrease in subsequent melanoma risk from 2% in the first year after diagnosis to a relatively stable rate of approximately 1% through a follow up of 15 years.

Study limitations included a small number of non-white patients (7.7% in the single primary melanoma group, 5.6% in the multiple primary melanoma group), the researchers reported.

“More intensive screening in the initial year after diagnosis may be indicated to identify new incident or prevalent cancers, but screenings should be continued thereafter,” the researchers concluded. “This may ultimately lead to earlier detection and decreased melanoma morbidity and mortality in these patients at high risk.” – By Bruce Thiel

Disclosure: Moore reports no relevant financial disclosures. Please see the full study for list of other researchers’ relevant financial disclosures.