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By Salynn Boyles, Contributing Writer, MedPage Today Reviewed by Robert Jasmer, MD; Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, BSN, RN, Nurse PlannerMohs micrographic surgery is the only recommended treatment option for high-risk facial nonmelanoma skin cancers.Note that Mohs micrographic surgery involves examining 100% of the surgical margins in three dimensions during surgery in an effort to remove as much cancerous tissue as possible while preserving healthy surrounding skin.Mohs micrographic surgery is the only recommended treatment option for high-risk facial nonmelanoma skin cancers, according to new guidelines.
When researchers from the University of Virginia reviewed data on the removal of close to 500 facial lesions, they concluded that margins of at least 8-mm are needed to excise 95% of basal cell carcinoma (BCCA) lesion using conventional surgical excision and a 13.25-mm margin would be required to remove 95% of high-risk squamous cell carcinomas (SCCA).
"This margin may be unreasonable on most areas of the face," lead researcher Amy E. Schell, MD, and colleagues wrote in the June 6 issue of JAMA Facial Plastic Surgery.
They added that, owing to the variability in margins found among high-risk nonmelanoma skin cancers as well as the relatively large margins needed to completely excise 95% of these lesions, "we continue to recommend the referral of high-risk cases for Mohs micrographic surgery."
The researchers further concluded that a 5-mm margin is required to remove at least 95% of low-risk nonmelanoma skin cancers and should be considered a minimum for primary excision.
Tumor grade, stage, and larger lesion size are associated with a higher risk of incomplete excision, the researchers wrote.
Other characteristics, such as a patient's age, sex, immune and disease status, and past sun exposure, have also been suggested as predictors of outcome, as has the location of the lesion on the face.
For basal cell carcinomas, the periorbital, perinasal, and preauricular regions as well as the ears and temple have been considered by some to be high-risk zones for lesions that are deeper and have greater lateral extensions.
These facial areas plus perioral tissue have been considered by some to be high-risk zones for squamous cell carcinoma, but the relevance of lesion location on patient outcome is still debated.
Mohs micrographic surgery (MMS) involves examining 100% of the surgical margins in three dimensions during surgery in an effort to remove as much cancerous tissue as possible while preserving healthy surrounding skin.
"Although MMS may be considered the gold standard for cutaneous nonmelanoma skin cancer removal, it is not always available or practical," the researchers wrote.
In their review, Schell and colleagues examined 495 lesions removed using MMS from 180 men and 119 women treated through the University of Virginia Health System from 2005 to 2011.
Based on history and histologic subtype, all lesions were grouped into either high-risk or low-risk categories, with high-risk lesions including those that were large, recurrent, or included aggressive subtypes: Lesions greater than or equal to 2 cm in either length or width were considered high risk, as were recurrent lesions.Moderately and well differentiated squamous cell cancers in situ were placed in the low-risk category.Nodular basal cell lesions were considered low risk.Infiltrative, morpheaform, micronodular, metatypical, sclerotic,
basosquamous, and multifocal and/or mixed basal cell carcinomas were considered high risk, as were superficial basal cell lesions.
Face location was not used to classify lesions as high- or low-risk because of the conflicting data."Overall, lesions required at least one high-risk attribute (recurrent status, large size, or aggressive histologic subtype) to be included in the high-risk group for either basal cell carcinoma or squamous cell carcinoma," Schell and colleagues wrote.
The mean margins for low-risk BCCAs, high-risk BCCAs, low-risk SCCAs, and high-risk SCCAs were 2.4 mm, 3.7 mm, 2.6 mm and 5.3 mm, respectively.
Among the other findings: Margins were significantly larger for lesions larger than 2 cm for both BCCA (5.6 mm and 2.7 mm, respectively; P<.001) and SCCA (4.5 mm and 3.1 mm, respectively; P=.02).This was also true for high-risk histologic subtypes versus low-risk histologic subtypes for BCCA (3.6 mm versus 2.7 mm; P<.001) as well as SCCA (6.2 mm versus 2.9 mm; P=.03).Recurrent BCCA lesions had significantly larger margins than primary lesion (4.3 mm and 2.8 mm, respectively; P=.03). Margins were larger for recurrent SCCA lesions (6.1 mm) versus primary lesions (3.1 mm), but the difference was not considered statistically significant (P=.06)
Lesion location appeared to have no significance for SCCA. Margins within the area of the face considered a high-risk zone were similar in size to those on other areas of the face (3.2 mm versus 3.5mm, respectively; P=.50).
For BCCA, margins in the high-risk zone were actually smaller than those outside the zone. (2.7 mm versus 3.4 mm, respectively; P=.01).
"The high-risk zones for BCCA and SCCA encompass perinasal, periocular, and auricular lesions, which, once removed, pose significant reconstructive challenges in terms of preserving function and cosmesis," the researchers wrote. "Practically speaking, most lesions within the high-risk zones for nonmalignant skin cancer will be candidates for Mohs micrographic surgery for this reason."
This study was previously reported at the American Academy of Facial Plastic and Reconstructive Surgery Combined Otolaryngological Spring Meeting in San Diego, April 20, 2012.
The authors report no conflict of interest.
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