Merkel cell carcinoma: treatment with bleomycin

Merkel cell carcinoma is the second most deadly form of skin cancer after melanoma, with a mortality rate of as high as 35 percent. It usually occurs as a deep red or purple dome-shaped tumor on sun-exposed skin of elderly people. Transplant recipients or AIDS patients have a higher incidence of this tumor than normal individuals. There is an association of a polyoma virus with this tumor that may explain the increased incidence in immunosuppression. Surgery, followed by radiation therapy is the standard of treatment. Sentinel node dissection is recommended because this tumor metastasizes often. Chemotherapy, such as is used for oat cell carcinoma of the lung, is advised for metastatic disease. However, systemic chemotherapy protocols have not been overly successful. We have treated four cases of stage-I Merkel cell carcinoma with surgery followed by intralesional bleomycin and have followed these cases for up to five years with no evidence of recurrence or metastasis. One case had radiation post operatively but the tumor recurred. Intralesional bleomycin caused complete regression of this tumor with minimal scarring and long term cure. Bleomycin, besides being a potent chemotherapy agent, has direct antiviral effects that may explain why this drug is so effective in treating Merkel cell carcinoma.