Paris - Most dermatologic surgeons can recall the frustration they felt the first time they received a histopathology report, stating the excision of the basal cell carcinoma (BCC) they performed on a patient had positive surgical margins, requiring a re-excision of the tumor. According to the results of a recent study, the location of the BCC, as well as the histologic type of the tumor, seems to play a central role in incomplete excision of basal cells.
David Farhi, M.D., department of dermatology and venereology, Hospital Tarnier, Paris, conducted a retrospective study on the rate and factors associated with pathologically reported incomplete excision of BCC without the use of Mohs micrographic surgery.
The BCCs were classified as superficial, nodular, morpheic, infiltrative, metatypic and multifocal types.
In the cases studied, the operators included 13 dermatologists and three head and neck or plastic surgeons.
The most frequent histologic types of the BCCs in the study were the superficial (35.3 percent) and the nodular (34.7 percent) variants, with the infiltrative type accounting for 26.7 percent of the cases. A Pinkus tumor and an actinic keratosis were associated in 2.2 percent and 2.5 percent of the cases, respectively.
Results showed that incomplete excision of these BCCs occurred in 10.3 percent of cases, including 8.6 percent of positive lateral margins and 2.5 percent of positive deep margins.
"We found that the face was very often the site of incomplete excision of basal cells such as around the nose, particularly the nasal ala, and around the eyelid, particularly the inner canthus. Incomplete excision was also strongly associated with the particular type of basal cell, namely the infiltrative and multifocal histologic subtypes.
"Conversely, lower rates of incomplete excision were significantly associated with extracephalic locations, and with nodular basal cells," Dr. Farhi says.
Reasons for incomplete excision
According to Dr. Farhi, the higher rates of incomplete excision of basal cell carcinoma in the head and neck region, especially on the nose, nasolabial folds, eyelids, ears and perioral area, are not so surprising, because surgery in these areas has cosmetic implications if larger, more generous excisions are performed, and surgeons likely want to be more conservative.
"Removing a basal cell carcinoma from extracephalic areas such as the chest is 'easier' in terms of the generous undermining one can do before the closing of the skin defect following excision of the tumor.
"The nasal ala or the inner canthus areas are a completely different story, because there is not so much tissue to work with, and in the latter, an ectropion can result if extreme care is not taken.
"Surgeons clearly want to steer clear of this adverse event, and, therefore, their incision is sometimes placed too close to the tumor margins," Dr. Farhi says.
According to Dr. Farhi, recurrent BCCs are at a higher risk of incomplete resection compared to primarily excised basal cells.
Dr. Farhi says a retrospective study has the advantage of offering an honest appraisal of how effective surgeons really are in clinical practice compared to a prospective study.
"In prospective studies, incomplete excision rates with standard surgery may be lower after re-excision.
"This may be because physicians might tend to operate more cautiously when they know that their surgical results are being monitored when competing in a randomized trial," Dr. Farhi says.