Squamous cell carcinoma with aggressive subclinical extension: 5-year retrospective review of diagnostic predictors

Background: Squamous cell carcinoma with aggressive subclinical extension (SCC-ASE) is a tumor whose extensive spread becomes revealed during surgery or pathologic review, particularly during Mohs micrographic surgery. Limited clinical awareness of these lesions may result in unanticipated longer surgical times and larger postoperative defects. SCC-ASE-associated clinical risk factors are not well studied. Objective: We sought to evaluate the incidence of and risk factors associated with SCC-ASE. Methods: We conducted a retrospective analysis of SCC treated with Mohs micrographic surgery between 2007 and 2012 at a single academic surgical center. SCC-ASE was defined as a lesion requiring at least 3 Mohs stages with a final surgical margin of >= 1 cm. Results: Of 954 cases studied, 31% were SCC-ASE. In multivariable analysis, sex (P = .001), history of previous nonmelanoma skin cancer (P <.001), Fitzpatrick skin types II and III (P = .004 and <.001, respectively), immunosuppression related to solid organ transplant (P <.001), and cigarette use (P <.001) were significant predictors of SCC-ASE. Limitations: Single academic center selection bias, not-controlled for sun exposure differences, no information on medication regimens of solid organ transplant patients, and a small sample size are all limitations of our study. Conclusion: Easily attainable demographic factors, especially immunosuppressed status and cigarette use, can help predict the occurrence of SCC-ASE and thereby optimize surgical planning and patient preparedness.