Risk of a Second Skin Cancer in a Cohort of Patients With Nonmelanoma Skin Cancer -Basal Cell Carcinoma or Squamous Cell Carcinoma-Treated With Mohs Micrographic Surgery: A National Prospective Cohort Study. / Riesgo de aparición de segundas neoplasias cutáneas en una cohorte de pacientes diagnosticados de carcinoma queratinocítico (carcinoma basocelular y carcinoma epidermoide) tratados con cirugía de Mohs. Estudio de cohortes prospectivo nacional.

OBJECTIVE: Patients with nonmelanoma skin cancer (NMSC)-ie, basal cell carcinoma (BCC) or squamous cell carcinoma (SCC)-have an increased risk of developing a second skin cancer. The aim of this study was to describe the frequency, incidence per 1000 person-years, and predictors of a second skin cancer in a cohort of patients with NMSC treated with Mohs micrographic surgery (MMS). MATERIAL AND METHODS: Prospective study of a national cohort of patients with NMSC who underwent MMS at 22 Spanish hospitals between July 2013 and February 2020; case data were recorded in the REGESMOHS registry. The study variables included demographic characteristics, frequency and incidence per 1000 person-years of second skin cancers diagnosed during the study period, and risk factors identified using mixed-effects logistic regression. RESULTS: We analyzed data for 4768 patients who underwent MMS; 4397 (92%) had BCC and 371 (8%) had SCC. Mean follow-up was 2.4 years. Overall, 1201 patients (25%) developed a second skin cancer during follow-up; 1013 of the tumors were BCCs (21%), 154 were SCCs (3%), and 20 were melanomas (0.4%). The incidence was 107 per 1000 person-years (95% CI, 101-113) for any cancer, 90 per 1000 person-years (95% CI, 85-96) for BCC, 14 (95% CI, 12-16) per 1000 person-years for SCC, and 2 (95% CI, 1-3) per 1000 person-years for melanoma. More men than women developed a subsequent skin cancer (738 [61%] vs 463 [39%]). The main risk factors were a history of multiple tumors before diagnosis (relative risk [RR], 4.6; 95% CI, 2.9-7.1), immunosuppression (RR, 2.1; 95% CI, 1.4-3.1), and male sex (RR, 1.6; 95% CI, 1.4-1.9). CONCLUSION: Patients have an increased risk of developing a second tumor after MMS treatment of NMSC. Risk factors are a history of multiple tumors at diagnosis, immunosuppression, and male sex.

Mohs micrographic surgery in the elderly: comparison of tumours, surgery and first-year follow-up in patients younger and older than 80 years old in REGESMOHS.

BACKGROUND: The elderly population is increasing and more patients in this group undergo Mohs micrographic surgery (MMS). The few publications investigating MMS in elderly people conclude that it is a safe procedure; however, these are single-centre studies without a comparison group. OBJECTIVE: To compare the characteristics of patients, tumours, MMS and 1-year follow-up in patients younger than 80 years, with patients older than 80 years at the time of surgery. METHODS: Data was analysed from REGESMOHS, a prospective cohort study of patients treated with MMS. The participating centres were 19 Spanish hospitals where at least one MMS is performed per week. Data on characteristics of the patient, tumour and surgery were recorded. Follow-up data were collected from two visits; the first within 1 month postsurgery and the second within the first year. RESULTS: From July 2013 to October 2016, 2575 patients that underwent MMS were included in the registry. Of them, 1942 (75.4%) were aged <80 years and 633 (24.6%) were ≥80 years old. In the elderly, the tumour size was significantly higher with a higher proportion of squamous cell carcinoma. Regarding surgery, elderly more commonly had tumours with deeper invasion and required a higher number of Mohs surgery stages, leaving larger defects and requiring more time in the operating room. Despite this, the incidence of postoperative complications was the same in both groups (7%) and there were no significant differences in proportion of relapses in the first-year follow-up. CONCLUSION: The risk of short-term complications and relapses were similar in elderly and younger groups. MMS is a safe procedure in the elderly.