Merkel cell carcinoma has a higher post-treatment recurrence rate than other skin cancers

Patients treated for Merkel cell carcinoma (MCC) face a five-year recurrence rate of 40% -; significantly higher than the recurrence rates of melanoma and other skin cancers, according to a study published today in JAMA Dermatology.

Moreover, in the study cohort of more than 600 patients, 95% of MCC recurrences occurred within the first three years, suggesting that surveillance efforts should be focused on this period, the authors wrote. .

“Merkel cell cancer is a life-changing diagnosis. It can be time-consuming, expensive and exhausting to undergo clinic visits, imaging studies and blood tests. We now have data on intervals of time and the stages of cancer that deserve greater or lesser intensity of surveillance,” said Dr. Aubriana McEvoy, who led the research while at the University of Washington Medical School. She is currently a dermatology resident at Washington University in St. Louis.

Merkel cell cancer is a rare and aggressive skin cancer that is more often fatal than invasive melanoma and basal and squamous cell carcinomas. Merkel cell carcinoma is made up of cells that look a lot like “Merkel” cells which are a key part of the epidermis, the outer layer of the skin. Normal Merkel cells communicate touch-related information such as pressure and texture to the brain.

This study included 618 patients (37% women) whose age ranged from 11 to 98 years and whose median age was 69 years. In this cohort, the initial treatment (surgery, radiotherapy and systemic therapy) had a median duration of 90 days.

The authors sought to characterize the risk of post-treatment recurrence of MCC diagnosed at the pathological (listed below) and clinical stages. The risk of recurrence at one year was:

  • 11% among patients diagnosed with stage I disease
  • 33% among patients diagnosed with stage IIA/IIB disease
  • 30% among patients diagnosed with stage IIIA disease
  • 45% among patients diagnosed with stage IIIB disease
  • 58% among patients diagnosed with stage IV disease

The researchers found four factors associated with a higher risk of recurrence: older age, male gender, immunosuppression, and a known primary lesion amid clinically detectable lymph node disease.

As expected, the survival of the patients in the cohort strongly depended on the stage of the cancer at the time of diagnosis: the MCC-specific survival rate five years after treatment was 95% for patients diagnosed at stage I compared to 41% for patients diagnosed at stage IV.

MCC survival “is a more accurate measure of disease risk than overall survival,” the authors wrote, because patients, with a median age of 70 at diagnosis, are at “considerable” risk of death from conditions unrelated to cancer. Again, stage at diagnosis was associated with a significant difference: 90% of deaths in patients with stage IV disease were attributed to MCC, whereas only 57% of deaths in patients diagnosed at stage I were attributed to disease.

It’s a hard cancer to beat because it comes back; after optimal treatment in nearly half of patients. We want to help patients determine the remaining risk of recurrence they have at different times after diagnosis.”

Dr. Paul Nghiem, Chair of Dermatology, UW School of Medicine

He is the lead author of the study and a Merkel cell cancer expert.

He added that the UW database is probably the most comprehensive in the world for MCC case therapies and outcomes.

“These are all patients who have been followed meticulously to find out why they are doing well or not well. The size of the dataset has allowed us to see patterns more clearly, and we need data to optimize decision-making. decision,” Nghiem said. noted.

The incidence of MCC in the United States is low compared to other skin cancers, but it is also on a steep upward trajectory because the disease is closely associated with age. Around 3,200 cases will be diagnosed this year, according to a 2018 study by Nghiem and colleagues.

In contrast, approximately 100,000 new melanomas will be diagnosed this year. Basal cell carcinoma is much more common, with 3.6 million cases diagnosed each year, and squamous cell carcinoma has 1.8 million new cases per year, according to the Skin Cancer Foundation.

Each of these cancers has a significantly lower post-treatment recurrence rate than MCC, the authors noted: melanoma 19%, squamous cells 5-9%, basal cells 1-2%.


Journal reference:

McEvoy, AM, et al. (2022) Risk of Merkel cell carcinoma recurrence and mortality by cancer stage and time since diagnosis. JAMA Dermatology.

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