Non-Melanoma Skin Cancers Coverage from Every Angle

Factors Contributing to Recurrence of Invasive Squamous Cell Carcinoma

By: Sarah Campen, PharmD
Posted: Thursday, February 7, 2019

Invasive squamous cell carcinoma is typically treated by surgical excision, following established guidelines that recommend clinical linear measurements for clear histopathologic margins. A center in Australia prospectively examined 1,296 cases of squamous cell carcinoma excisions over 9 years, taking into account microscopic surface diameter, invasion depth, grade of differentiation, and anatomic site. The results of the study, which were published in the Journal of Cutaneous Pathology, revealed a recurrence rate of 1.7% in well-differentiated, 1.8% in moderately differentiated, and 6.4% in poorly differentiated squamous cell carcinoma.

“The grade of differentiation and anatomic site had a larger influence on recurrence rates compared to the histopathologic margins,” explained John H. Pyne, PhD, of the University of New South Wales, Sydney, Australia, and colleagues. “Poorly differentiated [squamous cell carcinoma] and ear or lip sites require wider surgical margins.”

The minimum average histopathologic margins for well, moderately, and poorly differentiated squamous cell carcinoma were 1.4 mm, 1.1 mm, and 1.3 mm, respectively. No recurrence occurred beyond a histopathologic margin of 3.5 mm for well-differentiated and 2.5 mm for moderately differentiated squamous cell carcinoma. The sites of the highest recurrence for well-differentiated squamous cell carcinoma by anatomic site were the lip (7.0%) and ear (4.6%), although the average microscopic margins were similar to cases located on other anatomic sites. The researchers also found that increased patient age was associated with a higher risk of recurrence.

“Future additional investigation may lead to recommendations on quantifying more specific surgical margins for [squamous cell carcinoma] adjusted for tumor dimensions, grade of differentiation, and anatomic site,” concluded Dr. Pyne and colleagues.

Disclosure: The study authors’ disclosure information may be found at

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