WEDNESDAY, July 24, 2024 -- For cutaneous squamous cell carcinoma (cSCC) of the scalp, deep histological margins <1 mm do not increase the risk of recurrence as long as the margins are clear and there is no concurrent invasion of the galea aponeurotica, according to a study published online July 22 in the Journal of the European Academy of Dermatology & Venereology.

Júlia Verdaguer-Faja, M.D., from the Universitat Autònoma de Barcelona in Spain, and colleagues conducted a multicenter retrospective observational cohort study and multivariate competing risk analysis to examine whether clear but close deep histological margins (<1 mm) confer a higher risk of recurrence in cSCCs of the scalp treated with wide local excision compared to deep histological margins of ≥1 mm. Data were included for 295 patients with 338 cSCCs.

The researchers observed no association for close deep histological margins with increased cumulative incidence of recurrence (subhazard ratio, 1.96; 95 percent confidence interval, 0.87 to 4.41). However, tumors that presented concurrent invasion of the galea aponeurotica and close deep margins had increased risk of recurrence compared to tumors without these factors (subhazard ratio, 3.52; 95 percent confidence interval, 1.24 to 10.01). Higher risk of recurrence was also seen for tumors with clear but close peripheral margins (<1 mm) (subhazard ratio, 5.01; 95 percent confidence interval, 1.68 to 14.97).

"Surgical excision of cSCCs of the scalp should include the galea to enable complete assessment of the excised tumor and avoid complications," the authors write. "These results may not be extrapolated to cSCCs from other locations, which do not share the particular anatomical characteristics of the scalp."

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