Factors Contributing to the Incomplete and Close Margin Excision of Head and Neck Basal Cell Carcinoma (BCC).

Background: Basal cell carcinoma (BCC) is the most common malignancy worldwide, occurring frequently on sun-exposed areas including the head and neck, where it is associated with relatively greater morbidity and complexity in treatment. The mainstay of treatment is surgical excision. Local recurrence has been shown to be reduced following excision with adequate microscopic margins; however, up to 25% of all excisions result in close or involved margins. This places great stress on the health system. The risk factors for incomplete excision are not yet fully understood. Our study aims to identify risk factors that contribute to incomplete or close margins in head and neck BCCs in an Australian tertiary Plastic and Reconstructive surgery unit.

Methods: A retrospective cohort study of patients undergoing excision of BCC in the head and neck region was undertaken between 2016 and 2020 at the Department of Plastic and Reconstructive Surgery at the Royal Hobart Hospital, Australia.

Results: Increased rates of incomplete excision were observed with aggressive subtypes of BCC-infiltrating (OR = 2.91, p = 0.001), micronodular (OR = 4.07, p = 0.001), basosquamous (OR = 14.74, p < 0.001) and sclerosing (OR = 3.65, p < 0.001) and those on the ear (OR = 3.00, p = 0.0001). The presence of perineural invasion is also strongly associated with increased rates of incomplete and close margins (OR = 7.67, p ≤ 0.001). Larger lesion diameter (p < 0.001) and depth of invasion (p < 0.001) were strongly associated with incomplete excision.

Conclusions: There is increased risk of incomplete excision of BCCs with aggressive subtype, location on the ear, and greater lesion diameter and depth of invasion. Careful screening of patients with these high-risk factors may help reduce incomplete or close margin excisions.