Melanoma Recurrence after Mohs surgery without Immunostaining.

This research article was recently published in this month’s issue of @DermSurg_ASDS.

Briefly, this is a study from a group in New Jersey that looked at 224 cases of melanoma that were treated with Mohs surgery over 10 years. They did it the old-fashioned way, without the use of immunostains which can sometimes highlight melanoma cells under the microscope.  For head and neck melanomas, there are very low recurrence rates (<1%) that were not invading at the time of Mohs surgery and 4% for those melanomas that were already invading. This rate is much lower than surgical removal (“wide local excision”) that typically occurs in an operating room by other surgical specialties. Melanomas removed with traditional surgical excision (not Mohs surgery) have a 2-10% chance of coming back, depending on the surgical site.

Some disadvantages to this study include how they oversimplified the grouping of melanomas. They should have divided the non-invasive melanomas into lentigo maligna and lentigo maligna melanomas, which are two very separate processes and have different prognoses. Half of the patients in the study did not have follow up data. The average follow up period was ~3 years for those that followed up in the study, which means we do not have a complete grasp of the long term (5-10 year) follow up data.  

Mohs surgery has the advantage of looking at the entire boundaries of the skin that is removed. Even though the skin around a melanoma may appear normal with the naked eye, melanomas can extend their tentacles far beyond the recommended edges of normal skin (“skin margin”) that are removed. Some of the older research articles by Dr. Zitelli’s group in Pittsburgh also showcase a 0% tumor recurrence without the use of new immunostains and with 10-20 years of data, highlighting that the traditional approaches are extremely effective. 

Although the average patient in this study had only 3 years of a follow up, this study is a fantastic addition to the research literature on how we treat melanoma. It suggests that Mohs surgery can be better than other forms of surgery at removing melanoma and preventing it from coming back, especially if tumors are on the head and neck.