By Marilynn Larkin
NEW YORK (Reuters Health) - 3/10/2019
Mohs micrographic surgery (MMS) may be an effective alternative to wide margin excision (WME) for appropriately selected patients with early-stage invasive melanoma, a large retrospective study suggests.
"Our study adds to the growing body of evidence that early-stage melanoma may be effectively treated with MMS," Dr. Sean Christensen of Yale School of Medicine in New Haven said in an email to Reuters Health. "Previous national studies have found that melanoma of the head and neck - of any stage, including in situ disease - treated with MMS has improved survival relative to WME, and several single-institution studies have found decreased local recurrence for several subtypes of melanoma with MMS versus WME."
Dr. Christensen and colleagues studied 70,319 patients (median age, 57; 52.3% men; 97% white) with AJCC-8 stage I melanoma in the US National Cancer Database from 2004 through 2014.
As reported online September 25 in JAMA Dermatology, 67,085 were treated with WME and 3,234 with MMS. Overall survival was 95.2% at three years, 90.9% at five years and 80% at 10 years with WME, and 95.4%, 90.5%, and 79%, respectively, with MMS.
After controlling for covariates with multivariable and propensity score-matched analyses, patients treated with MMS had better overall survival, with hazard ratios of 0.86 and 0.82, respectively.
Further analyses showed that academic facilities were more likely to use MMS than nonacademic facilities (odds ratio, 2.03).
"This study is not likely to directly change clinical practice," Dr. Christensen said. "Many melanomas are already treated with MMS. A recent study found that the use of MMS for melanoma in the US has increased steadily over the last 15 years, with 7.9% of cases treated with MMS in 2016. Our study provides additional support for this practice, and the trend of increasing utilization of MMS for melanoma is likely to continue."
He noted that current guidelines "do not mention MMS or other forms of variable-margin excision with complete peripheral and deep microscopic margin analysis. Based on our findings and similar recent studies in the literature, guidelines should be updated to allow for and encourage the use of MMS or other margin-controlled surgery for melanoma."
Dr. Ian Maher of the University of Minnesota in Minneapolis, author of a related editorial, commented by email, "My group published an article a couple of weeks ago showing the superiority of survival with Mohs for for all head and neck melanomas (http://bit.ly/354b4Tz). I think what these two studies reinforce is that Mohs has a valuable role to play in the treatment of wide local excisions," he told Reuters Health.
"At a minimum, guidelines should be altered to emphasize that Mohs and other full-margin examination techniques should be recommended if deviation from the recommended margins is being considered," he said. "Ultimately, we should perform prospective comparative studies to truly establish the best treatment for our melanoma patients."
JAMA Dermatol 2019.
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