Chemotherapy (primary and recurrent disease)

Chemotherapy has shown activity in Merkel cell carcinoma (MCC) in the neoadjuvant, adjuvant, and metastatic/recurrent setting, but responses are not durable and toxicity is not insignificant, especially in a patient population where the median age at diagnosis is 69. The data available to date has not shown a benefit in disease-free or overall survival. However, there are several limitations when attempting to draw conclusions regarding the use of chemotherapy in MCC. First, the majority of data comes from retrospective analyses with limited numbers of patients per treatment center and significant bias with regard to patient inclusion. Randomized controlled studies would certainly be helpful, but this is difficult given the rarity of the disease. Second, there is heterogeneity within many of the individual studies in the stage of patients treated, how chemotherapy is administered (adjuvantly, concurrently with radiation, in a metastatic setting, or as second- or third-line therapy), and in the chemotherapy regimens used. For now, since the literature is not definitive, clinicians should decide on the use of chemotherapy in MCC on an individual personalized basis. This chapter will summarize many of the reported trials which have been conducted in this unusual malignancy.