title: Predictors of extensive subclinical spread in nonmelanoma skin cancer treated with Mohs micrographic surgery.
abstract: BACKGROUND
  In nonmelanoma skin cancer, the clinically visible portion may represent a small fraction of microscopic tumor spread. Previous studies have examined individual risk factors for subclinical spread based on patient and tumor characteristics. However, these risk factors have not been prioritized or studied in combination.
  
  
  OBJECTIVE
  To identify the most predictive risk factors for extensive subclinical tumor spread.
  
  
  METHODS
  Retrospective analysis of 1131 Mohs micrographic surgical cases. Variables analyzed included patient age, sex, and immune status and lesion size, location, histologic subtype, and recurrence. Logistic regression was applied to identify important combinations of tumor characteristics and to quantify relative odds of spread.
  
  
  METHODS
  Academic referral center.
  
  
  METHODS
  Consecutive sample of all referred patients treated by a single Mohs micrographic surgeon in a 3-year period.
  
  
  METHODS
  Number of Mohs micrographic surgical layers required to clear a tumor, with 3 or more layers defined as extensive subclinical spread.
  
  
  RESULTS
  The highest-risk tumors, with odds ratios greater than 6.0, were basosquamous and morpheaform basal cell carcinoma (BCC) on the nose, morpheaform BCC on the cheek, and those with a preoperative size greater than 25 mm. Other important risk factors were recurrent and nodular BCC on the nose; location on the eyelid, temple, or ear helix; neck tumors and recurrent BCC in men; and tumor size greater than 10 mm. Patients younger than 35 years were at lower risk. Increasing age and immunocompromise were not significant predictors.
  
  
  CONCLUSIONS
  Identification of lesions likely to exhibit extensive subclinical spread can help guide management to ensure complete tumor eradication and thereby reduce the risk of recurrence and its associated morbidity and cost.
authors.affiliation: Department of Dermatology, Stanford University School of Medicine, CA, USA.
authors.forename: R Sonia
authors.initials: RS
authors.lastname: Batra
authors.forename: Larisa C
authors.initials: LC
authors.lastname: Kelley
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008545:Melanoma / Q000473:pathology* / Q000601:surgery*; D008875:Middle Aged; D015580:Mohs Surgery; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local / Q000209:etiology* / Q000473:pathology*; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors; D012878:Skin Neoplasms / Q000473:pathology* / Q000601:surgery*