Second primary melanoma tied to better survival than single primary lesions

Patients who present with second primary melanomas have better survival and thinner lesions than those presenting with single primary melanomas, reveals a study.

“Patients with single primary melanomas have an increased risk of developing subsequent melanomas,” the authors said. “Secondary tumours diagnosed within and after 3 months are termed ‘synchronous’ and ‘asynchronous,’ respectively.

This retrospective cohort study compared tumour distributions and survival characteristics between patients with second primary melanomas and those with single primary melanomas. The authors obtained data from an institutional database from 14,029 patients with a diagnosis of a primary melanoma seen between 1970 and 2004.

Both the synchronous and asynchronous cohorts showed significantly improved survival probabilities than the single primary cohort (p=0.04 and p=0.002, respectively).

Single primary lesions appeared substantially thicker than the first-identified synchronous and asynchronous lesions (2.2 vs 2.0 and 1.7 mm, respectively). Moreover, synchronous lesions were more often anatomically concordant than asynchronous lesions (55.7 percent vs 38.2 percent; p<0.001).

“Our reported tumour distributions support the role of full body skin examinations, with attention to the region of initial diagnosis,” the authors said.

This study was limited by its single-centre design and the incomplete records for second primary melanoma Breslow depth and histopathology.