Prospective cohort
The study cohort consisted of 618 patients with MCC. The median age of the patients was 69, and 227 (37%) were women. The patients were enrolled within 6 months of their diagnosis in the prospective data repository from 2003 through 2019. Of this group, 223 had a recurrence of MCC.
As noted, there was a high risk of recurrence within 1 year, ranging from 11% for patients with pathologic stage I tumors to 58% for those with stage IV disease, and 95% of all recurrences occurred within 3 years of definitive therapy.
To get a better picture of the natural history of MCC recurrence, the investigators studied a cohort of patients with pathologically confirmed MCC who were prospectively enrolled from January 2003 through April 2019 in a data repository maintained at the University of Washington.
In addition to disease stage, factors associated with increased recurrence risk in univariable analyses include immunosuppression (hazard ratio, 2.4; P < .001), male sex (HR, 1.9; P < .001), known primary lesion among patients with clinically detectable nodal disease (HR, 2.3; P = .001), and older age (HR, 1.1, P = .06 for each 10-year increase).
Of the 187 patients in the cohort who died during the study, 121 died from MCC. At 4 years after diagnosis, MCC-specific survival rates were 95% for patients with pathologic stage I, 84% with stage IIA/IIB, 80% with stage IIIA, 58% with stage IIIB, and 41% with stage IV.
Evidence supports close monitoring within the first 3 years for patients with stage I-II MCC. Local recurrence within or adjacent to the primary tumor scar was associated with a 5-year MCC-specific survival rate of 85%, compared with 88% of patients with stage I or II disease who did not have recurrences.
“Because more than 90% of MCC recurrences arise within 3 years, it is appropriate to adjust surveillance intensity accordingly. Stage- and time-specific recurrence data can assist in appropriately focusing surveillance resources on patients and time intervals in which recurrence risk is highest,” the authors wrote.
“If you’re a patient who has not had your cancer come back for 3, 4, or 5 years, you can really cut down on the intensity of your follow-up and scans,” Dr. Nghiem said.
“We do now have two excellent blood tests that are working very well, and we have really good ways to detect the cancer coming back early, and that’s important, because we have potentially curative therapies that tend to work better if you catch the cancer early,” he said.
The study was supported by the National Institutes of Health. Dr. Nghiem reported personal fees and institutional support outside the study from several companies and patents for Merkel cell therapies with the University of Washington and University of Denmark. Dr. Demehri has disclosed no relevant financial relationships.
A version of this article first appeared on Medscape.com.