Objectives To characterize the natural history of Merkel cell carcinoma (MC
C) and to analyze the influence of patient, tumor, and treatment-related va
riables on survival and recurrence.
Summary Background Data Approximately 425 cases of MCC have been described
in the literature. This study represents the largest experience reported.
Methods A review was performed of patients who had been treated at Memorial
Sloan-Kettering Cancer Center for MCC between 1969 and 1996. Follow-up dat
a were available for 102 of the 109 (94%) patients identified.
Results The overall 5-year disease-specific survival rate was 74%. The medi
an follow-up was 35 months. For all patients, the only independent predicto
r of survival was the tumor stage at presentation. For patients with stage
I disease, the tumor size at presentation was also an independent predictor
of survival. Recurrence of disease occurred in 55 patients (55%), and the
most common site of first recurrence was within the draining lymph nodes (n
= 35). Elective lymph node dissection was the only parameter independently
predictive of improved relapse-free survival. The overall disease-specific
survival rate after recurrence was 62%. Predictors of improved disease-spe
cific survival after recurrence included nodal as compared to local or dist
ant recurrence, the ability to render the patient free of disease after rec
urrence, and a disease-free interval of >8 months.
Conclusion The prognosis for patients with MCC is favorable, and even after
recurrence the majority of patients experience long-term survival. Incorpo
ration of size into the staging system more accurately predicts survival in
patients with stage I disease. Although elective lymph node dissection dec
reased the rate of recurrence, it was not associated with improved overall
survival.