SAN DIEGO The decision for or against Mohs surgery must be based on a combination of criteria that includes histology, anatomy, type of patient, and type of tumor, Dr. Lynn Proctor Shipman said at a meeting sponsored by the American Society for Mohs Surgery.
Recurrent basal cell or squamous cell carcinomas are among the strongest indicators for Mohs surgery, said Dr. Shipman of the University of California, San Diego.
The advantages of Mohs surgery include a high cure rate and its status as an outpatient procedure (except in very difficult cases) that often preserves more tissue than do other cancer treatments. The disadvantages include the expense of staff and equipment and the need for specialized surgical training. Mohs also can be time consuming and tedious, and the procedure can be traumatic for the patient, she said.
There are no solid recurrence data comparing tumor treatment modalities. The differences among tumors, among patients, and among surgeons do not make for effective controlled studies, Dr. Shipman noted.
However, Mohs has demonstrated higher cure rates for primary and recurrent basal cell and squamous cell carcinoma compared with other treatments, including radiation.
Not all patients make good candidates for Mohs surgery. A frail or elderly patient, or a patient who would be too traumatized by the size of the defect in a Mohs procedure, should not receive the procedure (SKIN & ALLERGY NEWS, August 2005, p. 1).
Factors that make someone a good candidate for Mohs are the presence of infiltrating or micronodular tumors, aggressive tumors, or perineural invasion.
Dr. Shipman suggested that Mohs surgeons assessing patients should remember the five Cs:
Cure. The first treatment has the highest chance of cure, and Mohs cure rates are higher than those of other modalities.
Complications. Consider the medical status of the patients. Take a patient's blood pressure before you operate, and be aware of his or her medications.
Cosmesis. Mohs is often touted as tissue sparing, although preservation of function should be the most important goal. That said, a Mohs surgeon can often satisfy patients with a functional and cosmetically acceptable outcome.
Convenience. Although some waiting time is involved, Mohs is reasonably convenient for most patients.
Cost. Mohs is expensive, but radiation can be more expensive, and the cost of treating recurrent tumors can add up. Be sure to document the reasons for Mohs surgery in the patient's records to ensure Medicare coverage.
Certain anatomic sites with high recurrence rates are also indications for Mohs surgery.
The nose, for instance, is the bread and butter of Mohs. "There's almost never a day when I don't operate on the nose, especially the nasal tip," Dr. Shipman said. Mohs also is indicated for functionally significant sites, such as the finger, and in cases when a favorable cosmetic result is desired.
Immunocompromised patients are often candidates for Mohs surgery because of their increased susceptibility to tumors. "The longer they have been on immunosuppressant drugs, the greater the risk of tumor formation," Dr. Shipman noted. Unlike other patients, immunocompromised patients have a higher risk of squamous cell carcinoma than of basal cell carcinoma, particularly among cardiac patients, she added.
It is also important to remember that Mohs is not always successful, and is not recommended for oral, pharyngeal, or laryngeal tumors.
"Remember that many tumors require adjunctive therapy and a multidisciplinary approach for successful resolution," Dr. Shipman said.
Surgeons who are just beginning to perform Mohs surgery should consult colleagues from other disciplines before tackling multifocal or aggressive tumors, she emphasized.