Diagnosis of an additional in situ melanoma does not influence survival for patients with a single invasive melanoma: A registry-based follow-up study

Using a large (N= 25 493) population-based cohort from Queensland, Australia, we compared melanoma survival among cases with a single invasive melanoma only against those who also had a diagnosis of a single in situ melanoma. After adjustment for sex, age, body site, clinicopathological subtype, thickness and ulceration, it was found that there was no difference (P = 0.99) in 10-year melanoma-specific mortality following a diagnosis of an invasive lesion, whether or not an in situ melanoma was also present. We conclude that in situ melanomas do not alter the prognosis of an invasive melanoma.