{"doi":"10.1016/j.jdin.2021.04.002","title":"Comparison of community pathologists with expert dermatopathologists evaluating Breslow thickness and histopathologic subtype in a large international population-based study of melanoma","abstract":"To the Editor: As of 2019 National Cancer Institute data show that melanoma is the fifth most common cancer in the United States.1National Cancer InstituteCancer Stat Facts: melanoma of the skin. SEER.https://seer.cancer.gov/statfacts/html/melan.htmlDate accessed: April 28, 2021Google Scholar There has been a recent push to include the histopathologic subtype of nodular melanoma as an independent prognostic classifier due to the identification of associated aggressive histopathologic characteristics and shorter recurrence-free times.2Lattanzi M. Lee Y. Simpson D. et al.Primary melanoma histologic subtype: impact on survival and response to therapy.J Natl Cancer Inst. 2019; 111: 180-188Crossref PubMed Scopus (34) Google Scholar,3Dessinioti C. Dimou N. Geller A.C. et al.Distinct clinicopathological and prognostic features of thin nodular primary melanomas: an international study from 17 centers.J Natl Cancer Inst. 2019; 111: 1314-1322Crossref PubMed Scopus (17) Google Scholar We used the population-based, Genes, Environment, and Melanoma (GEM) study,4Begg C.B. Hummer A.J. Mujumdar U. et al.A design for cancer case-control studies using only incident cases: experience with the GEM study of melanoma.Int J Epidemiol. 2006; 35: 756-764Crossref PubMed Scopus (60) Google Scholar to assess the levels of agreement between community pathologists, those who originally diagnosed the melanoma, and expert study dermatopathologists, who reviewed the lesion for complete histology, histopathologic subtype, and Breslow thickness. The salient components of the GEM study were that it was population-based, multi-country size, and included disease-specific mortality data and re-review of hematoxylin-eosin–stained tissues by dermatopathologists. We evaluated how histopathologic subtype misclassification might impact the reported disease-specific mortality. Our study included 1957 individuals with a first primary melanoma diagnosed in the year 2000, at centers of the GEM study in Australia, Canada, Italy, and the United States. The Institutional Review Board approval was obtained, and the subjects signed written consent. Each patient had their hematoxylin-eosin–stained slides read initially by a community pathologist, who reported Breslow thickness and histopathologic subtype followed by an independent review by a dermatopathologist, blinded to the community pathologist report. The vital status was obtained at an average of 7.4 years. Within the study population and lethal melanoma cases, descriptive statistics were calculated and the frequency tables that compared the kappa value for the readings of community pathologists and dermatopathologists were created for Breslow thickness and histopathologic subtype. All the tests were two-sided and P < .05 was considered significant. The data were analyzed using SAS 9.4 software and the interobserver variability was calculated with Fleiss' method.5Fleiss J.L. Levin B. Paik M.C. Statistical Methods for Rates and Proportions.3rd ed. John Wiley & Sons, Inc., 2003Crossref Google Scholar The mean age of the subjects at diagnosis was 55 years and 48.5% of them were women. The kappa for Breslow thickness was 0.72 (95% CI, 0.69-0.75), demonstrating a “substantial agreement.” The kappa within lethal cases was 0.56 (95% CI, 0.45-0.66), suggesting a “moderate agreement.” The overall kappa for the histopathologic subtype of 0.27 demonstrates only a “fair agreement” (Table I), whereas that for the reviewing dermatopathologists was 0.68, indicating a “substantial agreement.” The kappa for nodular subtype had only 51.3% agreement. Within the lethal cases, the kappa value was “fair,” 0.30 (Table II).Table IConcordance of histopathologic subtype between community pathologists and dermatopathologistsDermatopathologistsCommunity pathologistsSSMNMLMMALMSCNOSOtherTotalSSM919†Numbers in bold represent the number of subjects for which community pathologists and dermatopathologists agreed.337033523NM5596†Numbers in bold represent t","journal":"JAAD International","year":2021,"id":202495,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":6,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9518,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2021-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":782575,"name":"Baillie Bronner","orcid":"0000-0002-7546-856X","position":1,"is_corresponding":false},{"id":526894,"name":"Stefano Rosso","orcid":"0000-0001-6816-2661","position":2,"is_corresponding":false},{"id":527694,"name":"Lynn From","orcid":null,"position":3,"is_corresponding":false},{"id":250486,"name":"Klaus J. 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Begg","orcid":"0000-0003-3772-1795","position":22,"is_corresponding":false},{"id":500611,"name":"Marianne Berwick","orcid":"0000-0001-5062-2180","position":23,"is_corresponding":false},{"id":782576,"name":"Isidora Autuori","orcid":"0000-0002-0288-8416","position":28,"is_corresponding":false},{"id":597119,"name":"Pampa Roy","orcid":null,"position":29,"is_corresponding":false},{"id":288021,"name":"Anne S. Reiner","orcid":"0000-0002-1258-6112","position":30,"is_corresponding":false},{"id":503374,"name":"Tawny W. Boyce","orcid":"0000-0002-8972-5539","position":32,"is_corresponding":false},{"id":310333,"name":"Terence Dwyer","orcid":"0000-0002-2091-7663","position":37,"is_corresponding":false},{"id":526893,"name":"Richard P. Gallagher","orcid":"0000-0003-2365-0391","position":39,"is_corresponding":false},{"id":468426,"name":"Joseph D. 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