Prospective, randomized comparison helps delineate MMS role in BCC treatment

Maastricht, The Netherlands - Available results from a prospective randomized study comparing Mohs' micrographic surgery (MMS) and surgical excision for facial basal cell carcinomas (BCCs) indicate MMS should be the treatment of choice for primary aggressive lesions and recurrent tumors, according to Nicole W.J. Smeets, M.D., Ph.D., department of dermatology, University Hospital, Maastricht and colleagues.

The study divided lesions into primary and recurrent groups, and within each of those categories, the tumors were randomized equally to surgical excision or MMS. Nearly 400 primary BCCs and about 200 recurrent tumors were treated.

Recurrence rate is being analyzed as the primary endpoint, but defect size, cosmetic appearance judged by the patient and a six-member panel of professionals and laymen, along with operation-related cost were also investigated as outcomes.

Recommendations The recommendation of the investigators regarding the role of MMS is based on results that show:

"We believe ours is the first trial that prospectively compares treatment with MMS versus surgical excision for facial BCC, and although our follow-up period is relatively short, we already see a small difference in recurrence rates in favor of MMS. Besides this difference we noticed much larger defect sizes in surgical excision when tumors could not be eradicated in a single excision in comparison to MMS. Incomplete surgical excision was especially likely in the case of histopathologically aggressive primary BCCs and recurrent BCCs, and so we believe MMS is preferable to use for these tumors to avoid larger defects, a poor aesthetic outcome and functional problems," Dr. Smeets explains.

Methodology The inclusion criteria for the study required primary BCCs to have a histologically-confirmed diagnosis, measure at least 1 cm in diameter and be located in the H zone of the face. Tumors ≥1 cm with an aggressive histopathological subtype were also eligible without fulfilling the location requirement.

BCCs recurring for a first or second time were eligible for enrollment in the recurrent group. In addition, all patients had to have a life expectancy of at least three years, and the investigators are planning a five-year follow-up.

The protocol for standard excision used a 3 mm margin with excision at a 90-degree angle into subcutaneous fat. Re-excision for tumors found to have a positive margin was also performed with a 3 mm margin; four tumors that were not completely excised after two procedures were then treated with MMS. A 3 mm margin was used as well for the MMS procedures.

"It is common to use smaller margins when performing MMS. However, we wanted to standardize the margins between our two treatment modalities," Dr. Smeets explains.

Thus far, the results show recurrence rates for primary tumors are 2 percent for surgical excision and 3 percent for MMS; corresponding rates for recurrent lesions are 0 percent and 3 percent. Surgical excision failed to completely remove 18 percent of primary BCCs on the first attempt and 32 percent of recurrent BCCs. Among the primary BCCs, 25 percent of histopathologically aggressive carcinomas compared with 12 percent of non-aggressive tumors were incompletely excised, and the difference in those rates was statistically significant.

Surgical excision and MMS were associated with similar mean defect sizes for the primary (4.64 mm vs. 4.06 mm) and recurrent tumors (7.76 mm vs. 6.50 mm). In almost all cases, reconstruction was done immediately, and cosmetic outcomes were comparable for the two types of procedures as well.