SKIN - July 2021 - 1251 proof returned SKIN July 2021 Volume 5 Issue 4 Copyright 2021 The National Society for Cutaneous Medicine 403 RESEARCH LETTER The Impact of the COVID-19 Pandemic on Skin Cancers Treated with Mohs Micrographic Surgery: A Retrospective Analysis at a Single United States Academic Institution Laila F. Abbas, BA1, Jennifer Wang, BA1, Rajiv I. Nijhawan, MD1, Divya Srivastava, MD1 1UT Southwestern Medical Center, Department of Dermatology, Dallas, Texas The coronavirus disease 2019 (COVID-19) pandemic led to changes in practice among skin cancer surgeons, especially through restrictions placed on elective procedures, leading to a negative impact on skin cancer care.1-4 Preliminary studies in the United Kingdom plastic surgery literature showed the short-term negative impact of the European lockdown on skin cancer outcomes, demonstrating that patients seen during the first wave of the pandemic had larger, more aggressive tumors with an increase in incomplete excision margins.1,5 Prior studies in the United States literature have also shown that the COVID-19 pandemic led to delayed diagnosis and care for patients with skin cancer.6 However, there remains limited data on the effect of these delays on skin cancer surgery outcomes, including stage of surgery and tumor size. To fill this gap, additional studies are warranted to determine the impact of the COVID-19 pandemic on Mohs Micrographic Surgery (MMS) outcomes. The aim of this single center retrospective study was to determine changes in skin cancers treated with MMS at a large, U.S. medical center in the context of evolving COVID-19 pandemic restrictions over the course of several months. MMS case logs identified patients treated with MMS for skin cancer from March– September 2020 and March–September 2019. Inclusion criteria included a diagnosis of skin cancer treated with MMS. Medical records were accessed using the electronic medical record. All pertinent patient and pathologic characteristics were documented. Statistical analysis included Kruskal-Wallis, unpaired t-tests, and Chi-square tests. This study included 1150 patients treated for 1307 tumors. The majority of patients were non-Hispanic (79%), white (89%) and male (73%). The most common tumor was basal cell carcinoma (BCC) (43%), followed by squamous cell carcinoma (34%). 536 patients treated with MMS during the study period in 2020 were compared to 614 seen in 2019 (Table 1). Age, gender, and race/ethnicity of patients were comparable between both groups, as was type of tumor being treated. Patients treated in 2020 were strikingly more likely to be immunosuppressed (34% versus 13%, p< 0.0001), and trended towards having larger tumors, both factors likely impacting providers’ decisions to treat, as these features could indicate more aggressive skin cancers. Patients seen in 2020 also had a greater difference between pre-operative tumor size and post-operative defect size, SKIN July 2021 Volume 5 Issue 4 Copyright 2021 The National Society for Cutaneous Medicine 404 Table 1. Comparison of Patient Demographic and Clinical Characteristics. Table 1 depicts demographic and clinical characteristics of patients seen in 2019 compared to those seen in 2020. Patients seen in 2020 were much more likely to have recurrent tumors, were strikingly more likely to be immunosuppressed, had a greater difference in pre- and post-operative tumor size, and had an increased number of stages required for treatment. 2019 2020 p-value Number of Patients 614 536 Number of Tumors 698 609 Age, median (IQR) 73 (66-79) 72 (64-79) nsa Age, mean (SD) 72 (11) 71 (11) Gender, n (%) nsb Male 441 (72%) 399 (74%) Female 173 (28%) 137 (26%) Ethnicity, n (%) nsc Non-Hispanic 486 (79%) 432 (81%) Hispanic 22 (4%) 29 (5%) Unknown 106 (17%) 75 (14%) Race, n (%) nsc White 556 (91%) 481 (90%) Asian 2 (0%) 1 (0%) Native American 2 (0%) 2 (0%) Other/Unknown 54 (9%) 52 (10%) Immunosuppression, n (%) 80 (13%) 180 (34%) <0.0001b Type of Tumor, n (%) nsc BCC 321 (46%) 242 (40%) SCC 229 (33%) 213 (35%) SCCIS 102 (15%) 112 (18%) MIS 34 (5%) 33 (5%) KA 10 (1%) 6 (1%) Other 2 (0%) 3 (0%) Pre-operative tumor size, cm2, mean (SD) 1.70 (2.58) 1.72 (3.72) nsa Post-operative defect size, cm2, mean (SD) 4.91 (6.08) 5.47 (8.1) nsa Difference in pre/post-operative size, cm2, mean (SD) 3.21 (4.19) 3.75 (5.22) 0.03a Number of Stages, n (%) 0.03c 1 360 (52%) 297 (49%) 2 271 (39%) 228 (35%) 3 51 (7%) 55 (9%) 4 14 (2%) 17 (3%) 5+ 2 (0%) 11 (2%) Number of Stages, mean (SD) 1.61 (0.74) 1.73 (0.95) 0.01a Type of Repair, n (%) nsc Simple closure 471 (77%) 444 (81%) Second intention 151 (25%) 126 (21%) Primary closure 320 (52%) 318 (58%) Advanced repair 140 (23%) 104 (19%) Advancement flap 38 (6%) 44 (8%) Transposition flap 7 (1%) 13 (2%) Rotation flap 31 (6%) 19 (3%) Full thickness skin graft 26 (4%) 15 (3%) Xenograft 9 (1%) 3 (1%) Other (combination) 29 (4%) 10 (2%) Referral to other specialist for repair, n (%) 87 (12%) 61 (10%) Tumor Status, n (%) 0.02b Primary 682 (98%) 605 (99%) Recurrent 26(2%) 4 (1%) Abbreviations: ns: non-significant; IQR: interquartile range; SD: standard deviation; BCC: basal cell carcinoma, SCC: squamous cell carcinoma; SCCIS: squamous cell carcinoma in situ; MIS: melanoma in situ; KA: keratoacanthoma; cm: centimeter aValues computed with Kruskal-Wallis Test bValues computed with Fischer’s Exact Test cValues computed with Chi-Square Test SKIN July 2021 Volume 5 Issue 4 Copyright 2021 The National Society for Cutaneous Medicine 405 (3.75 centimeters squared (cm2) versus 3.21cm2, p=0.03), and required more MMS stages (mean 1.73 versus 1.61 stages in 2019, p=0.01, with a higher proportion of patients requiring three or more stages in 2020, p=0.03), suggesting an increase in subclinical spread of tumors potentially due to delay in presentation and subsequent treatment. However, patients seen in 2020 and 2019 had equivalent rates of advanced reconstruction such as flaps or grafts compared to primary closure or second intention. The COVID-19 pandemic brought a significant disruption in non-emergent procedures, not only through governmental restrictions but also through changes in patient behavior. With COVID-19-related changes and restrictions, patients presented with larger tumors and required more MMS stages. Treatment of high-risk, immunosuppressed patients was prioritized, and low-risk patients may have delayed treatment due to the pandemic. Limitations of this study include that it is a single-center study at a tertiary referral center, potentially leading to overrepresentations of more severe presentations and its limited long- term outcome data. Future analysis will be required to see long-term effects on skin cancer outcomes in subsequent years. Providers should be aware of the potential effects of the COVID-19 pandemic on skin cancer surgery and outcomes, with potential associated morbidity and mortality, in the context of preparation for long-term post- pandemic sequelae, and additionally in preparation for any future large-scale pandemics or care interruptions. Conflict of Interest Disclosures: None Funding: None Corresponding Author: Divya Srivastava, MD 5939 Harry Hines Boulevard POB2, Suite 400 Phone: 214-645-8950 divya.srivastava@utsouthwestern.edu References: 1. Nolan GS, Dunne JA, Kiely AL, et al. The effect of the COVID-19 pandemic on skin cancer surgery in the United Kingdom: a national, multi-centre, prospective cohort study and survey of Plastic Surgeons. BJS (British Journal of Surgery). 2020;107(12):e598-e600. 2. Geskin LJ, Trager MH, Aasi SZ, et al. Perspectives on the recommendations for skin cancer management during the COVID-19 pandemic. J Am Acad Dermatol. 2020;83(1):295- 296. 3. Earnshaw CH, Hunter HJA, McMullen E, Griffiths CEM, Warren RB. Reduction in skin cancer diagnosis, and overall cancer referrals, during the COVID-19 pandemic. Br J Dermatol. 2020;183(4):792-794. 4. Andrew TW, Alrawi M, Lovat P. Reduction in skin cancer diagnoses in the UK during the COVID-19 pandemic. Clin Exp Dermatol. 2021;46(1):145- 146. 5. Capitelli-McMahon H, Hurley A, Pinder R, Matteucci P, Totty J. Characterising non- melanoma skin cancer undergoing surgical management during the COVID-19 pandemic. Journal of plastic, reconstructive & aesthetic surgery : JPRAS. 2020:S1748-6815(1720)30539- 30538. 6. Marson JW, Maner BS, Harding TP, et al. The magnitude of COVID-19's effect on the timely management of melanoma and nonmelanoma skin cancers. J Am Acad Dermatol. 2021;84(4):1100-1103.