A unique set of debate accompanies the guidelines. Namely, controversy has surrounded the classification of most primary superficial basal cell carcinomas as appropriate for treatment by MMS. These tumors have comparable cure rates when treated by MMS or curettage and cryosurgery, are often multifocal and require more Mohs stages than other basal cell carcinoma subtypes, and largely lack data on recurrence and invasion.19 The guidelines also have been scrutinized for including only studies from the United States.20 Furthermore, the report is largely based on expert opinion rather than evidence.
Some Mohs surgeons have concerns that the guidelines will minimize clinical judgment. Nonetheless, deviations from the AUC practiced by Mohs surgeons have been reported where clinical judgment supplants guideline criteria. The most commonly cited reasons for performing MMS on tumors classified as uncertain or inappropriate, according to one study by Ruiz et al,21 included performing multiple MMSs on the same day, tumor location on the lower legs, and incorporation into an adjacent wound. Reported discrepancies in the AUC further emphasize the importance of clinical judgment and call into question the need for future revision of the criteria.22 For example, a primary squamous cell carcinoma in situ greater than or equal to 2 cm located on the trunk and extremities (excluding pretibial surfaces, hands, feet, nail units, and ankles) in a healthy patient is categorized as appropriate, while a recurrent but otherwise identical squamous cell carcinoma in situ is categorized as uncertain. These counterintuitive criteria are unsupported by existing studies.
Controversies in Subspecialty Certification
Recently, debate also has surfaced regarding subspecialty certification. Over the last decade, proponents of subspecialty certification have argued that board certification would bring consistency and decrease divisiveness among dermatologists; help to prevent exclusion of Mohs surgeons from insurance networks and teaching opportunities at the Veterans Administration; and demonstrate competence to patients, the media, and payers. Those in opposition contest that practices may be restricted by insurers using lack of certification to eliminate dermatologists from their networks, economic credentialing may be applied to dermatologists such that those without the subspecialty certification may not be deemed qualified to manage skin cancer, major limitations may be set determining which dermatologists can sit for the certification examination, and subspecialty certification could create disenfranchisement of many dermatologists. A 2017 American Academy of Dermatology member survey demonstrated ambivalence regarding subcertification, with 51% of respondents pro-subcertification and 48% anti-subcertification.23
Nonetheless, after years of debate the American Board of Dermatology proposed subspecialty certification in Micrographic Dermatologic Surgery, which was approved by the American Board of Medical Specialties on October 26, 2018. The first certification examination will likely take place in 2 years, and a maintenance of certification examination will be required every 10 years.24
Further investigation is needed to elucidate and optimize solutions to many of the current controversies associated with MMS.