Dermatology: Practical and Conceptual Research Letter | Dermatol Pract Concept. 2025;15(2):5219 1 Diversity Gaps in Clinical Practice Guidelines for Cutaneous Malignancies: A Focus on Melanoma, Basal Cell Carcinoma, and Squamous Cell Carcinoma Courtney A. Chau1, Subin Lim2, Rachel Granovsky3, Lillian Sidky3, Eudora Lee3, Gabriela A. Cobos2 1 Icahn School of Medicine at Mount Sinai, New York, USA 2 Department of Dermatology, Tufts Medical Center, Boston, USA 3 Tufts University School of Medicine, Boston, USA Key words: Clinical Practice Guidelines, Skin Neoplasms, Melanoma, Basal Cell Carcinoma, Squamous Cell Carcinoma Citation: Chau CA, Lin S, Granovsky R, Sidky L, Lee E, Cobos GA. Diversity Gaps in Clinical Practice Guidelines for Cutaneous Malignancies: A Focus on Melanoma, Basal Cell Carcinoma, and Squamous Cell Carcinoma. Dermatol Pract Concept. 2025;15(2):5219. DOI: https://doi.org/10.5826/dpc.1502a5219 Accepted: December 17, 2024; Published: April 2025 Copyright: ©2025 Chau et al. This is an open-access article distributed under the terms of the Creative Commons Attribution- NonCommercial License (BY-NC-4.0), https://creativecommons.org/licenses/by-nc/4.0/, which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original authors and source are credited. Funding: None. Competing Interests: None. Authorship: All authors have contributed significantly to this publication. Corresponding Author: Gabriela A. Cobos, MD. Department of Dermatology, Tufts Medical Center. 260 Tremont Street, 13 th and 14 th floors, Boston, MA 02116. ORCID ID: 0009-0002-9470-2881. E-mail: gabriela.cobos@tuftsmedicine.org Introduction The lack of diversity in dermatology research samples is well documented. An analysis revealed that 61% of United States dermatology guidelines did not include skin of color keywords [1]. No research has examined diversity in the re- search informing the American Academy of Dermatology (AAD) cutaneous malignancy guidelines. This study eval- uated patient diversity in the studies supporting the AAD treatment guidelines for cutaneous squamous cell carcinoma (cSCC), basal cell carcinoma (BCC), and melanoma. Case Presentation References supporting treatment recommendations were extracted from the AAD melanoma, BCC, and cSCC clini- cal guidelines. From each reference, publication year, study design, allocation model, clinical trial phase, study loca- tion(s), sample size, sex, age, race, and ethnicity data, if available, were recorded. References that precluded access to the abstract and body were excluded (N=4). Analysis was conducted using R 4.1.2 (R Foundation for Statistical Computing, Vienna, Austria). 2 Research Letter | Dermatol Pract Concept. 2025;15(2):5219 The guidelines for melanoma, cSCC, and BCC contained 147, 59, and 94 treatment-related references, respectively. Experimental designs (N=109, 36.3%) and retrospective chart reviews (N=91, 30.3%) were the most cited. North America (N=99, 33.0%) and Europe (N=89, 29.7%) were the most frequent study locations. Only 5.3% of studies reported patients from South America, Asia, or Africa (Table S1). Only 45/248 (18.1%) references with patient-level data (melanoma: 9.6%, cSCC: 20.9%, BCC: 30.0%) reported race and/or ethnicity (Table 1). White/Caucasian was the most reported race, with 25/45 references (55.6%) report- ing exclusively white samples. Population-based cohorts of melanoma, cSCC, and BCC cases had 96.5%, 90.0%, and 90.0% white patients, respectively [2,3]. The BCC references reported higher percentages of white patients compared to the population-based cohort (P=0.002, Wilcoxon signed- rank test). Of 45 studies reporting race and/or ethnicity, 23 (51.1%), 18 (40.0%), and 9 (20.0%) had study sites in North America, Europe, and Australia/Oceania, respectively. The distribution of study locations in the race-reporting ref- erences was not different from the overall distribution of study locations (Fisher’s exact text, P=0.9029). Conclusion Our study highlights the lack of diversity reported in the patient populations of research informing cutaneous ma- lignancy treatment guidelines. Over 50% of race- reporting references had exclusively white patients. While white pop- ulations have the highest skin cancer risk, skin of color patients have a higher mortality rate, often due to delayed detection [4]. Therefore, skin of color representation in treatment-related research is essential, despite white pre- dominance in cases. Only 18.1% of studies with patient-level data reported race or ethnicity, corroborating the issue of ra- cial and ethnic underreporting in dermatology research. An evaluation of the AAD atopic dermatitis guideline references also demonstrated racial underreporting and underrepresen- tation [5]. Limitations include potential data collection in- consistencies between researchers and exclusion of studies published after the guidelines (2017/2018). Additionally, only 18.1% of studies reported race and/or ethnicity, lim- iting the generalizability of the claim of limited diversity. Some studies may not have reported race or ethnicity due to population homogeneity or sensitivity of the topic. None- theless, race and ethnicity remain underreported. Improving diversity and including South America, Africa, and Asia in research is imperative for developing treatment guidelines that apply to all patients. References 1. Pan CX, Yang K, Nambudiri VE. Assessment of the represen- tation of black, indigenous and people of colour in dermatol- ogy clinical practice guidelines. Br J Dermatol. 2022;187(3): 443-445. DOI: 10.1111/bjd.21273. PMID: 35349171. 2. Paulson KG, Gupta D, Kim TS, et al. Age-Specific Incidence of Melanoma in the United States. JAMA Dermatol. 2020;156(1): 57-64. DOI: 10.1001/jamadermatol.2019.3353. PMID: 31721989. 3. Lukowiak TM, Aizman L, Perz A, et al. Association of Age, Sex, Race, and Geographic Region With Variation of the Ratio Table 1. Patient Characteristics Reported in the Treatment-Related References. Melanoma (N=125) cSCC (N=43) BCC (N=80) Sample size, median (IQR) 212 (58.5 – 677.5) 151 (41.5 – 613.5) 124.5 (42.5 – 301.25) Percentage of female participants, median (IQR) 42.7 (38.1 – 53.1) 39.3 (24.7 – 46.5) 38.7 (32.9 – 46.9 Age range, median (IQR) 64.25 (52 – 71) 59 (39 – 70) 57 (44 – 67) Mean age, median (IQR) 65 (56.65 – 69.25) 66 (62.7 – 70.075) 66 (62.1 – 68) Median age, median (IQR) 59 (52 – 68.25) 68 (66.5 – 75.5) 66.5 (62 – 68.625) Race/Ethnicity percentage of participants, median (IQR) 12 (9.6) 9 (20.9) 24 (30.0) White 99.6 (98.2 – 100) 97.9 (92.9 – 100.0) 100 (97.3 – 100) Black 0 (0 – 0) 0 (0 – 0) 0 (0 – 0) Asian 0 (0 – 0.05) 0 (0 – 0) 0 (0 – 0) Hispanic or Latino 0 (0 – 0.2) 0 (0 – 2.5) 0 (0 – 0) American Indian or Alaska Native 0 (0 – 0) 0 (0 – 0) 0 (0 – 0) Native Hawaiian or Pacific Islander 0 (0 – 0) 0 (0 – 0) 0 (0 – 0) More than one race 0 (0 – 0) 0 (0 – 0) 0 (0 – 0) Unknown 0 (0 – 0) 0 (0 – 0) 0 (0 – 0) N=number of references with patient level data. Research Letter | Dermatol Pract Concept. 2025;15(2):5219 3 of Basal Cell to Cutaneous Squamous Cell Carcinomas in the United States. JAMA Dermatol. 2020;156(11):1192-1198. DOI: 10.1001/jamadermatol.2020.2571. PMID: 32845319. 4. Gupta AK, Bharadwaj M, Mehrotra R. Skin Cancer Concerns in People of Color: Risk Factors and Prevention.  Asian Pac J Cancer Prev. 2016;17(12):5257-5264. Published 2016 Dec 1. DOI: 10.22034/APJCP.2016.17.12.5257. PMID: 28125871. 5. Roster K, Xie L, Feroz FF, Lipner SR. Under- Representation of Racial Minorities and Under-Reporting of Race and Eth- nicity in Studies Used to Inform 2014 Atopic Dermatitis Clinical Guidelines: A Cross-Sectional Analysis. Dermatitis. 2024;35(S1):S103-S104. DOI: 10.1089/derm.2023.0025. PMID: 37347967.