A risk scale for predicting extensive subclinical spread of nonmelanoma skin cancer

Abstract

Background: The clinical appearance of nonmelanoma skin cancer may represent only a portion of microscopic tumor invasion.

Objective: To develop a scale based on high-risk characteristics for predicting the probability of extensive subclinical spread of nonmelanoma skin cancer.

Methods: Retrospective analysis of 1095 Mohs micrographic surgical cases (MMS) yielded high-risk factors for extensive tumor spread, defined as requirement of greater-than-or-equal3 MMS layers. Predictive characteristics included: any BCC on the nose, morpheaform BCC on the cheek, neck tumors and recurrent BCC in men, location on the eyelid, temple, or ear helix, and size>10 mm. Multivariate logistic regression was applied to develop a risk index.

Results: Tumor characteristics were assigned point values calculated from the respective odds of extension and categorized into six risk classes with probabilities of extensive subclinical spread ranging from 10% to 56%.

Conclusion: A risk scale simplifies and enhances prediction of extensive tumors. The associated probabilities can help to guide patient preparation and appropriate therapy.