Recurrence rates of cutaneous squamous cell carcinoma of the head and neck after Mohs micrographic surgery vs. standard excision: a retrospective cohort study

Background Recurrent cutaneous squamous cell carcinoma (cSCC) has been associated with an increased risk of local functional and aesthetic comorbidity, metastasis and mortality. Objectives To compare the risk of recurrence between Mohs micrographic surgery (MMS) and standard excision for cSCC of the head and neck. Methods This was a retrospective cohort study of all patients with a cSCC treated with MMS or standard excision at the departments of dermatology of a secondary or tertiary care hospital in the Netherlands between 2003 and 2012. To detect all recurrences, patients were linked to the Dutch pathology registry. To compare the risk of recurrence between MMS and standard excision, hazard ratios (HRs) were used adjusted for clinical tumour size > 2 cm and deep tumour invasion. Results A total of 579 patients with 672 cSCCs were included: 380 cSCCs were treated with MMS and 292 with standard excision. The risk of recurrence was 8% (22 of 292) after standard excision during a median follow-up of 5 center dot 7 years [interquartile range (IQR) 3 center dot 5-7 center dot 8], which was higher than the 3% (12 of 380) after MMS during a median follow-up of 4 center dot 9 years (IQR 2 center dot 3-6 center dot 0). The cumulative incidence of recurrence was higher for standard excision than for MMS during the entire follow-up period of 8 center dot 6 years. Carcinomas treated with MMS were at a three times lower risk of recurrence than those treated with standard excision when adjusted for tumour size and deep tumour invasion (adjusted HR 0 center dot 31, 95% confidence interval 0 center dot 12-0 center dot 66). Conclusions MMS might be superior to standard excision for cSCCs of the head and neck because of a lower rate of recurrence.