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Mohs micrographic surgery comparable to wide local excision for melanoma in situ

There were no significant differences in outcomes for patients with melanoma in situ who were treated with Mohs micrographic surgery compared with those treated with wide local excision, the current standard of care, according to study results published in JAMA Dermatology.

The researchers retrospectively reviewed a prospective database of 2,299 patients with a diagnosis of primary melanoma treated with either wide local excision (WLE) or Mohs micrographic surgery (MMS). Patients with invasive melanoma were excluded, and 662 patients were included in the study: 277 treated with MMS (mean age, 64 years; 62.1% male) and 385 treated with WLE (mean age, 58.5 year; 54.8% male).

Patients had been treated per standard of care in dermatology and surgery between 1978 and 2013 at an academic tertiary care center. There was a median follow-up of 8.6 years.

MMS was used more frequently on the face (80.2%) and scalp and neck (8.3%) compared with WLE (36.7%, 6.8%, respectively; P < .001).

The MMS cohort had an overall recurrence rate of 1.8%, compared with 5.7% in the WLE cohort (P = .07), with a mean time to recurrence of 3.91 years after MMS and 4.45 years after WLE.

The MMS cohort had a 5-year recurrence rate of 1.1% compared with 4.1% in the WLE cohort (P = .07). The calculated 10- and 15-year recurrence rates for MMS treatment were 1.8% and 5%, respectively, while the 10- and 15-year recurrence rates for WLE treatment were 6.8% and 7.3%, respectively.

The surgical margin taken for WLE-treated tumors was greater for recurring tumors vs. non-recurring tumors (P = .003).

There was a 92% 5-year overall survival for the MMS cohort and 94% for the WLE cohort. Two patients in the MMS cohort and 13 patients in the WLE cohort died of melanoma, with a mean time to death due to melanoma of 6.5 years in the MMS cohort and 6.1 years in the WLE cohort.

“We found that the 5-, 10- and 15-year recurrence rates of [melanoma in situ] treated with MMS were not different than for WLE, the currently widely accepted and preferred mode of therapy,” the researchers wrote. “Patients who underwent MMS had similar outcomes by several measures compared with those who underwent WLE: rate of occurrence, mean time to all-cause and melanoma-specific death, overall survival and melanoma-specific survival.”

“Future studies, including a randomized study comparing MMS with WLE, are needed, but may be problematic to implement, given patients’ desires to try to preserve anatomic function and cosmesis; a well-designed prospective study would be informative,” the researchers concluded. “Further study to assess whether there are functional or perceived cosmetic differences or adverse outcomes for patients treated with MMS vs. WLE would be illuminating.”  – by Bruce Thiel

Disclosure: The researchers report no relevant financial disclosures.