title: Etiologic and other factors predicting nevus-associated cutaneous malignant melanoma.
abstract: Cutaneous malignant melanomas with histologic evidence of an associated nevus (N+) may have a different risk factor profile from that of melanomas without it (N-). To address this question, a case-only analysis of 932 people with cutaneous malignant melanoma was done to identify etiologic and other factors associated with N+ melanoma. Evidence of an associated nevus was found in 36% of melanomas. N+ melanomas were thinner (Ptrend=0.0009) and more likely to be of the superficial spreading type than other types of melanoma. Subjects with N+ melanomas were younger (Ptrend<0.0001) and reported a higher nevus density on their skin than subjects with N- melanomas [odds ratio (OR), 3.1; 95% confidence interval (CI), 1.6-6.0, for high nevus density versus no nevi]. Indicators of high accumulated sun exposure were less prevalent among subjects with N+ melanomas (OR, 0.3; 95% CI, 0.2-0.4, for melanoma location on the head and neck versus location on trunk; OR, 0.2; 95% CI, 0.1-0.4, for severe solar elastosis adjacent to the melanoma versus no elastosis; OR, 0.2; 95% CI, 0.1-0.4, for lentigo maligna melanoma subtype versus superficial spreading subtype). With the exception of solar elastosis and age, all of the aforementioned variables remained significantly associated with N+ melanomas in multivariate analyses. No associations with self-reported measures of sun exposure, sunburn, or pigmentation phenotype were apparent. Our findings provide some support for the hypothesis of etiologically separate pathways for melanoma, with N+ melanomas appearing less likely to develop in the presence of characteristics suggesting high accumulated sun exposure than N- melanomas. However, it is possible that high UV exposure causes involution of nevi, thus reducing the density of nevi in exposed skin and thereby the probability of N+ melanoma.
authors.affiliation: Division of Preventive Oncology, Cancer Care Ontario, Toronto, Canada. purduem@mail.nih.gov
authors.forename: Mark P
authors.initials: MP
authors.lastname: Purdue
authors.forename: Lynn
authors.initials: L
authors.lastname: From
authors.forename: Bruce K
authors.initials: BK
authors.lastname: Armstrong
authors.forename: Anne
authors.initials: A
authors.lastname: Kricker
authors.forename: Richard P
authors.initials: RP
authors.lastname: Gallagher
authors.forename: John R
authors.initials: JR
authors.lastname: McLaughlin
authors.forename: Neil S
authors.initials: NS
authors.lastname: Klar
authors.forename: Loraine D
authors.initials: LD
authors.lastname: Marrett
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008545:Melanoma / Q000209:etiology / Q000473:pathology*; D008875:Middle Aged; D015337:Multicenter Studies as Topic; D009508:Nevus, Pigmented / Q000209:etiology / Q000473:pathology*; D012042:Registries; D012878:Skin Neoplasms / Q000209:etiology / Q000473:pathology*; D012880:Skin Pigmentation; D013472:Sunlight / Q000009:adverse effects; D011795:Surveys and Questionnaires