title: Multiple primary melanomas among 16,570 patients with melanoma diagnosed at Kaiser Permanente Northern California, 1996 to 2011.
abstract: BACKGROUND
  Published rates of cutaneous multiple primary melanoma (MPM) vary widely.
  
  
  OBJECTIVE
  We examined incidence of and risk factors associated with MPMs among Kaiser Permanente Northern California members.
  
  
  METHODS
  We estimated MPM incidence among 16,570 patients with melanoma from 1996 through 2011. We compared characteristics between patients with MPMs and single primary melanomas and estimated crude and adjusted hazard ratios of MPMs using Cox models.
  
  
  RESULTS
  In all, 15,448 patients had a single melanoma and 1122 had MPMs. Patients with MPMs were older and more often male, non-Hispanic white, and partnered. Subsequent primary melanomas were diagnosed after a mean of 3.83 (SD 3.61, median 2.82) years and were more likely in situ and thinner than initial tumors. The risk of a subsequent melanoma decreased from 2% in the first year after diagnosis to a stable approximately 1% rate through 15 years of follow-up.
  
  
  CONCLUSIONS
  We lacked data on some known melanoma risk factors and had small numbers of non-white patients and certain tumor subtypes.
  
  
  CONCLUSIONS
  The risk of MPMs, although highest in the first year after diagnosis, remains stable thereafter. Those at highest risk of MPMs are older, male, white, and partnered. Clinicians should be aware of the rate of MPMs and recognize high-risk subgroups.
authors: Department of Dermatology, The Permanente Medical Group, Walnut Creek, California. Electronic address: Megan.m.moore@Kp.org.
authors: Megan M
authors: MM
authors: Moore
authors: Department of Social and Behavioral Sciences, Harvard School of Public Health, Boston, Massachusetts.
authors: Alan C
authors: AC
authors: Geller
authors: Division of Research, Kaiser Permanente Northern California, Oakland, California.
authors: E Margaret
authors: EM
authors: Warton
authors: Division of Research, Kaiser Permanente Northern California, Oakland, California.
authors: Joan
authors: J
authors: Schwalbe
authors: Division of Research, Kaiser Permanente Northern California, Oakland, California; Department of Dermatology, The Permanente Medical Group, Walnut Creek, California.
authors: Maryam M
authors: MM
authors: Asgari
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D002140:California / Q000453:epidemiology; D015331:Cohort Studies; D016208:Databases, Factual; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007345:Insurance Claim Review; D008297:Male; D008545:Melanoma / Q000453:epidemiology* / Q000473:pathology; D008875:Middle Aged; D009378:Neoplasms, Multiple Primary / Q000453:epidemiology* / Q000473:pathology; D016609:Neoplasms, Second Primary / Q000453:epidemiology* / Q000473:pathology; D015995:Prevalence; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D018570:Risk Assessment; D017678:Sex Distribution; D012878:Skin Neoplasms / Q000453:epidemiology* / Q000473:pathology; D016019:Survival Analysis; D000096142:Cutaneous Malignant Melanoma
keywords: incidence; melanoma; multiple primary melanoma; risk; screening; skin cancer