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Nodular melanoma is less likely than superficial spreading melanoma to be histologically associated with a naevus
Author(s) -
Pan* Yan,
Adler* Nikki R,
Wolfe Rory,
McLean Catriona A,
Kelly John W
Publication year - 2017
Publication title -
medical journal of australia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.904
H-Index - 131
eISSN - 1326-5377
pISSN - 0025-729X
DOI - 10.5694/mja17.00232
Subject(s) - medicine , melanoma , breslow thickness , odds ratio , superficial spreading melanoma , dermatology , trunk , nodular melanoma , nevus , pathological , cancer , pathology , breast cancer , sentinel lymph node , ecology , cancer research , biology
Objectives: To determine the frequency of naevus‐associated melanoma among superficial spreading and nodular subtypes; and to investigate associations between naevus‐associated melanoma and other clinico‐pathological characteristics. Design, setting and participants: Cross‐sectional study of all patients with nodular and superficial spreading melanomas diagnosed between 1994 and 2015 at the Victorian Melanoma Service, Melbourne. Methods and main outcome measures: Clinical and pathological characteristics of naevus‐associated and de novo melanomas were assessed in univariable and multivariable logistic regression analyses. Results: Of 3678 primary melanomas, 1360 (37.0%) were histologically associated with a naevus and 2318 (63.0%) were de novo melanomas; 71 of 621 nodular (11.4%) and 1289 of 3057 superficial spreading melanomas (42.2%) were histologically associated with a naevus. In multivariable analyses, the odds of being associated with a naevus were higher for melanomas located on the trunk ( v head and neck: adjusted odds ratio [OR], 2.27; 95% CI, 1.73–2.96; P < 0.001), while the odds were lower for thicker tumours (adjusted OR, 0.75 per millimetre increase in Breslow thickness; 95% CI, 0.69–0.81; P < 0.001), amelanotic/hypomelanotic melanomas (adjusted OR, 0.68; 95% CI, 0.48–0.97; P = 0.035), and older age (patients 70 years or older v patients under 30 at diagnosis: adjusted OR, 0.28; 95% CI, 0.20–0.40; P < 0.001). After adjusting for confounders, the odds of an associated naevus was three times as high for superficial spreading melanomas as for nodular melanomas (adjusted OR, 3.05; 95% CI, 2.24–4.17; P < 0.001). Conclusion: Melanomas are most likely to arise in the absence of a pre‐existing naevus, particularly nodular melanomas. Public health campaigns should therefore emphasise the detection of suspicious de novo lesions, as well as of changing lesions.