Survival for Patients With Single and Multiple Primary Melanomas

Abstract

Subsequent melanomas in patients with multiple primary melanomas (MPMs) are well known to be thinner, on average, than the prior melanomas and might therefore have a better outcome.^1-3 Whether survival is better or worse for patients diagnosed with MPMs rather than a single primary melanoma (SPM) is important for prognosis. Results from earlier studies^4-7 examining survival of patients with SPMs and MPMs offer little consistent information; the studies included few patients, limited analysis to selected stage categories, or presented crude survival estimates only. A recent assessment based on 4952 patients with stage I or II SPMs and 298 with stage I or II MPMs from a melanoma clinic suggested that patients with MPMs survived longer than those with an SPM after taking account of other prognostic factors.⁸ Among possible mechanisms for an apparent survival benefit, the authors discuss whether multiple melanomas may provoke a stronger host immune response,⁸ which might also explain better survival for patients with MPMs than for those with SPMs after diagnosis of metastatic disease.⁹ In addition, the possibility that initial and subsequent melanomas are thinner in MPMs than in SPMs has given rise to speculation that MPM may differ biologically from SPM.^2,10