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Background/objectives In melanoma management, sentinel lymph node biopsy (SLNB) is used to stage patients and to indicate prognosis. More recently, it has been used to select patients for adjuvant therapy. This study aimed to report knowledge of and attitudes towards SLNB for patients with melanoma among Australian dermatologists. Methods Mixed methods study using cross-sectional questionnaires (n = 88) and semi-structured interviews (n = 13), May-September 2019. Results Of the dermatologists surveyed, 56% thought SLNB had an important role in melanoma management, 26% were unsure and 18% thought SLNB unimportant. Of the 92% who would discuss SLNB with their patients, the main stated value of SLNB was for assessing eligibility for adjuvant therapies (79%); only 60% indicated SLNB was of value for providing prognostic information, and just over half (53%) thought it could improve staging. Interview data indicated that attitudes towards SLNB are shifting among dermatologists, driven by data from landmark clinical trials and the influence of professional networks. Accordingly, interviewees adopted one of three positions in relation to SLNB: (a) believed in utility of SLNB and adhered to the guidelines; (b) were unconvinced about utility of SLNB but adhered to the guidelines; and (c) were unconvinced about utility of SLNB and did not adhere to the guidelines. Conclusion Although most of the dermatologists surveyed were familiar with and follow the SLNB recommendations, some disagreement with and distrust of the recommendations was evident. Greater acceptance of the SLNB recommendations appeared to be driven by the improved outcomes demonstrated in stage III patients receiving adjuvant systemic therapy.

Background People at high risk of developing melanoma are usually identified by pigmentary and naevus phenotypes. Objective We examined whether associations of these phenotypes with melanoma risk differed by ambient sun exposure or participant characteristics in two population‐based, case–control studies with comparable ancestry but different ambient sun exposure. Methods Data were analysed from 616 cases and 496 controls from the Australian Melanoma Family Study and 2012 cases and 504 controls from the Leeds (UK) case–control study. Questionnaire, interview and dermatological skin examination data were collected using the same measurement protocols. Relative risks were estimated as odds ratios using unconditional logistic regression, adjusted for potential confounders. Results Hair and skin colour were the strongest pigmentary phenotype risk factors. All associations of pigmentary phenotype with melanoma risk were similar across countries. The median number of clinically assessed naevi was approximately three times higher in Australia than Leeds, but the relative risks for melanoma associated with each additional common or dysplastic naevus were higher for Leeds than Australia, especially for naevi on the upper and lower limbs. Higher naevus counts on the head and neck were associated with a stronger relative risk for melanoma for women than men. The two countries had similar relative risks for melanoma based on self‐reported naevus density categories, but personal perceptions of naevus number differed by country. There was no consistent evidence of interactions between phenotypes on risk. Conclusions Classifying people at high risk of melanoma based on their number of naevi should ideally take into account their country of residence, type of counts (clinical or self‐reported), body site on which the naevus counts are measured and sex. The presence of naevi may be a stronger indicator of a genetic predisposition in the UK than in Australia based on less opportunity for sun exposure to influence naevus development.

The contribution of melanocortin-1 receptor (MC1R) gene variants to the development of early-onset melanoma is unknown. Using an Australian population-based, case-control-family study, we sequenced MC1R for 565 cases with invasive cutaneous melanoma diagnosed between ages 18 and 39 years, 409 unrelated controls and 518 sibling controls. Variants were classified a priori into "R" variants (D84E, R142H, R151C, I155T, R160W, D294H) and "r" variants (all other nonsynonymous variants). We estimated odds ratios (OR) for melanoma using unconditional (unrelated controls) and conditional (sibling controls) logistic regression. The prevalence of having at least one R or r variant was 86% for cases, 73% for unrelated controls and 81% for sibling controls. R151C conferred the highest risk (per allele OR 2.57, 95% confidence interval 1.86-3.56 for the case-unrelated-control analysis and 1.70 (1.12-2.60) for the case-sibling-control analysis). When mutually adjusted, the ORs per R allele were 2.23 (1.77-2.80) and 2.06 (1.47-2.88), respectively, from the two types of analysis, and the ORs per r allele were 1.69 (1.33-2.13) and 1.25 (0.88-1.79), respectively. The associations were stronger for men and those with none or few nevi or with high childhood sun exposure. Adjustment for phenotype, nevi and sun exposure attenuated the overall log OR for R variants by approximately 18% but had lesser influence on r variant risk estimates. MC1R variants explained about 21% of the familial aggregation of melanoma. Some MC1R variants are important determinants of early-onset melanoma. The strength of association with melanoma differs according to the type and number of variants.

Mutation analysis of two genes involved in melanoma susceptibility (CDKN2A/p16INK4a and CDK4) was undertaken in 131 probands with a family history of melanoma. Screening of all three exons of CDKN2A and exon 2 of CDK4 by single-strand conformation polymorphism (SSCP) analysis and/or direct sequencing identified a total of 10 different CDKN2A germline mutations, including 6 not previously described in the germline. All but one has been previously proven to, or is likely to, affect the structure and function of p16INK4a. The incidence of CDKN2A mutation was 8.4% (11/131), but was significantly higher in families with three or more cases of melanoma (10/66, 15.1%) than in those in which only two relatives were affected (1/65, 1.5%). The incidence of CDKN2A mutation was also higher in families with three or more cases of melanoma and at least one member with multiple primary melanomas (6/19, 31.6%) than in similar families without multiple primary melanomas (4/47, 8.5%). One novel CDK4 variant of uncertain significance was found in a kindred that also carries a CDKN2A mutation. Genes Chromosomes Cancer 25:339–348, 1999. © 1999 Wiley-Liss, Inc.