Mohs Surgery Offers ‘Survival Advantage’ in Early Merkel Cell Carcinoma

Using Mohs micrographic surgery (MMS) significantly improved overall survival in patients with early-stage Merkel cell carcinoma (MCC) when compared with wide local excision (WLE), according to a recent study.

A study published in JAMA Dermatology determined that patients with early-stage, localized MCC had better overall survival (OS, period from the start of treatment where patients are still alive) when treated with MMS, compared with WLE. In particular, patients benefited from MMS if they had localized MCC, primary MCC tumors and pathologically confirmed negative lymph nodes treated with surgery.

Merkel cell carcinoma is a rare and aggressive type of skin cancer that either forms on or under the skin and typically on areas of the skin that are exposed to the sun. This type of cancer is more common among people who are older and have weaker immune systems, according to National Cancer Institute.

MMS is a type of procedure that is commonly used to treat skin cancer. “During Mohs micrographic surgery, the visible tumor and a thin layer of tissue around it is removed,” as defined by National Cancer Institute. “The tissue is then checked under a microscope for the presence of cancer cells at all edges of the tumor.”

A total of 2,313 patients were included in the JAMA Dermatology study, in which patients with MCC were treated across 649 centers. Of note, there were 160 centers that were academic facilities and treated 1,276 patients. There were 14 centers that were considered high-volume facilities, which treated 507 patients.

In terms of the centers where the participants were treated, the study authors noted that patient outcomes were better when they were treated at high-volume facilities. The authors stated that this finding could be because of experience with the disease and better access to clinical trials.

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The primary focus of the study was to determine overall survival (OS) after surgery, which is the length of time from diagnosis or treatment of cancer when patients remain alive after surgery. The authors of the study found that patients who received excision (a type of surgical procedure for the skin) with MMS demonstrated a significantly improved OS, compared with patients who received WLE, another type of surgical procedure, in which a scalpel is used to cut out the tumor and any normal tissue around it. The amount of normal tissue removed around the tumor depends on tumor size, according to National Cancer Institute.

From the results gathered by the data, the authors established that the mean survival was 97.1% for patients who received MMS after one year and 81.8% after 10 years. Patients who received WLE had a mean survival of 96.9% after one year and 60.9% after 10 years.

“This report provides preliminary data suggesting that treatment of localized, early-stage MCC with MMS may result in the most optimal patient survival outcomes for this aggressive form of skin cancer,” the study authors wrote. “The current study suggests that MMS may provide a survival advantage compared with WLE for surgical management of the MCC primary tumor. However, we controlled for use of adjuvant radiotherapy (radiotherapy given after primary surgery) in this analysis given previous workdemonstrating its efficacy.”

The authors recognized that MMS is an effective approach for patients with MCC. Nonetheless, this type of surgery is not “widely performed by Mohs surgeons and significantly trails WLE in use for this indication,” the authors wrote. “Therefore, it may follow that future efforts to expand use of MMS for MCC should first focus on high-volume regional MCC centers with an established infrastructure that allows these patients to be cared for from treatment to appropriate posttreatment follow-up.”

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