Ten Years of Scalp Keratinocyte Carcinomas (Basal Cell Carcinomas and Squamous Cell Carcinomas) Treated by Mohs Micrographic Surgery at a Large Australian Centre, a Descriptive Study.

BACKGROUND

There is a paucity of data on scalp keratinocyte carcinomas (KCs) referred for Mohs micrographic surgery (MMS). This study aimed to perform a descriptive analysis of scalp KCs-specifically basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs)-treated with MMS at The Skin Hospital in Sydney, Australia.

METHODS

We performed a retrospective analysis of all scalp KCs treated with MMS from October 2012 to September 2022 from an electronic database. Extracted data included age, sex, tumour histology and aggressiveness, anatomical location, preoperative tumour size, final defect size, number of MMS stages and sections, extensive subclinical spread and repair method.

RESULTS

We identified 1177 scalp KCs treated with MMS in 889 patients, consisting of 948 BCCs (80.5%) and 229 SCCs (19.5%). The median age of patients with BCCs was significantly younger (60 years) than that of SCCs (73 years) (p < 0.001). SCCs were more commonly found in males (182/229, 79%) (p < 0.001). The majority of KCs were located on the frontal scalp (948/1177, 55%). BCCs were more likely to be of an aggressive subtype (58%, 512/876) than SCCs (21%, 44/212) (p < 0.001). The median largest tumour and defect diameter was larger for SCCs than for BCCs (p < 0.001). There was no significant difference in the median number of MMS stages for tumour type (p = 0.121). Extensive subclinical spread was more common for aggressive SCCs (13/44, 29.5%) than for BCCs (84/511, 16.4%) (p = 0.028). Primary closure repair was most common (55%, 644/1177).

CONCLUSION

The observed differences in patient, tumour and treatment characteristics may help inform clinical practice and inspire further research.