Surgical Factors Contributing to Invasive Squamous Cell Carcinoma Recurrence
Invasive squamous cell carcinoma (SCC) is typically treated surgically, with guidelines in place recommending surgical margins for excision based on the SCC being classified as low or high risk. Researchers undertook a study to examine recurrence rates of SCC after surgical excision, taking into account microscopic surface diameter, invasion depth, grade of differentiation, and anatomic site. Findings were published by Pyne et al in the Journal of Cutaneous Pathology.
Study Methods
Prospective consecutives cases of SCC excision from a mixed referral and primary care skin cancer clinic in Sydney, Australia, were reviewed. These cases were collected from 2009 to 2017.
The closest surgical margin from the deep and lateral margins, microscopic tumor surface diameters, and invasion depth were all measured on excised tissue to the nearest 0.1 mm. By grade of differentiation, maximum average microscopic surface diameters ranged from 8.0 to 9.6 mm and maximum average depths ranged from 1.3 to 2.5 mm. Minimum average histopathologic margins for well, moderately, and poorly differentiated SCC were 1.4, 1.1, and 1.3 mm, respectively.
Findings
Recurrence of SCC occurred in 1.7% of well-differentiated cases (n = 18 of 1,084 patients), 1.8% of moderately differentiated cases (n = 3 of 165 patients), and 6.4% in poorly differentiated cases (n = 3 of 47 patients). Regarding histopathologic margin, no patients with a margin beyond 3.5 mm for well-differentiated SCC experienced recurrence, and no patients with a margin beyond 2.5 mm for moderately differentiated SCC experienced recurrence. The lip and the ear were the sites where there was the highest recurrence rate for well-differentiated SCC—7.0% and 4.6%, respectively.
The authors concluded, “We found a recurrence rate of 1.0% for histopathologic margins of 1.5 mm with early well-differentiated SCC. The grade of differentiation and anatomic site had a larger influence on recurrence rates compared to histopathologic margins. Poorly differentiated SCC and ear or lip sites require wider surgical margins.”
Disclosure: The study authors’ full disclosures can be found at onlinelibrary.wiley.com.
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