Clinical outcomes of high-risk cutaneous squamous cell carcinomas treated with Mohs surgery alone: An analysis of local recurrence, regional nodal metastases, progression-free survival, and disease-specific death

The incidence of cutaneous squamous cell carcinoma (cSCC) continues to increase, and it is now predicted that the number of deaths from cSCC will surpass that of melanoma within the next 5 years. Although most cSCCs are successfully treated, there exists an important subset of high-risk tumors that have the highest propensity for local recurrence (LR), nodal metastasis (NM), and disease-specific death (DSD). We investigated the clinical outcomes of high-risk cSCCs treated with Mohs surgery (MS) alone, analyzing LR, NM, distant metastasis, and DSD. In addition, we analyzed progression-free survival and DSD in patients who underwent salvage head/neck dissection for regional NMs. Retrospective review of all high-risk cSCC treated in our clinics between January 1, 2000, and January 1, 2020, with follow-up through April 1, 2020. Two university-affiliated, private-practice MS referral centers. In total, 581 high-risk primary cSCCs were identified in 527 patients, of which follow-up data were obtained for 579 tumors. The 5-year disease-specific survival was 95.7%, with a mean survival time of 18.6 years. The 5-year LR-free survival was 96.9%, the regional NM-free survival was 93.8%, and the distant metastasis–free survival was 97.3%. The 5- and 10-year progression-free survival rates from metastatic disease were 92.6 and 90.0%, respectively. In patients who experienced regional NMs and underwent salvage head and neck dissection with or without radiation, the 2-year disease-specific survival was 90.5%. Our cohort, which is the largest high-risk cSCC cohort treated with MS to date, experienced lower rates of LR, NM, and DSD than those reported with historical reference controls using both the Brigham and Women’s Hospital and American Joint Committee on Cancer, Eighth Edition, staging systems. We demonstrated that MS confers a disease-specific survival advantage over historical wide local excision for high-risk tumors. Moreover, by improving local tumor control, MS appears to reduce the frequency of regional metastatic disease and may confer a survival advantage even for patients who develop regional metastases.