Author Affiliations: Department of Dermatology, Eastern Virginia Medical School, Norfolk (Dr Hood); and Miraca Life Sciences Research Foundation, Irving, Texas (Dr Farmer).
A common task for dermatologists is treatment of primary and/or recurrent cutaneous squamous cell carcinoma (SCC). A biopsy specimen is taken to confirm the diagnosis, and the pathology report is reviewed for prognostic parameters of the tumor, which typically include degree of differentiation and margin involvement but may or may not comment on perineural invasion. Perineural invasion has long been considered to be an adverse prognostic parameter and is found in many other cutaneous malignant tumors, notably basal cell carcinoma, microcystic adnexal carcinoma, and melanoma. In SCC, involvement of large, named nerves documented by clinical signs, symptoms, or radiographic evidence is generally accepted as a significant adverse finding and is usually treated by adjuvant therapy following surgical removal. But what about microscopic nerve involvement seen on the diagnostic biopsy material or subsequent tissue obtained during surgical removal? Carter et al1 evaluated their experience in 114 cases of SCC with histologically documented perineural invasion managed in 2 academic centers over an 11-year period. They focused on the outcomes of patients with large vs small microscopic nerve involvement (diameter, ≥ 0.1 mm vs < 0.1 mm) and adjusted for other concomitant prognostic factors. Large-caliber nerve involvement (≥ 0.1 mm) was found to have an elevated risk of nodal metastasis and death, but these cases were associated with multiple other risk factors. Small-caliber nerve involvement had a much lower adverse risk. The authors advocate for the need of a larger study to fully evaluate the impact of nerve involvement based on size of nerves and number of involved nerves as independent prognostic variables.
Hood AF, Farmer ER. Data Needed for Management of Cutaneous Squamous Cell CarcinomaComment on “Outcomes of Primary Cutaneous Squamous Cell Carcinoma With Perineural Invasion”. JAMA Dermatol. 2013;149(1):41-42. doi:10.1001/jamadermatol.2013.1474