Therapy And Survival

In general, therapeutic options are similar to treatment of multiple myeloma, except that more intensive therapy is needed, and outcomes are significantly inferior.

The outcome of 68 patients from the literature with well-documented primary PCL treated before 1986 has been described.27 Fifty-two of the patients received a single alkylating agent, mainly melphalan with or without prednisone, as initial therapy. A complete or partial response was documented in 28 patients (54%). The median duration of survival was slightly more than 1 year in patients who responded to therapy, but less than 1 month for nonresponding patients. The other 16 patients were treated with combination chemotherapy, which resulted in a response rate of 75% and a median duration of survival for all 16 patients of 9.5 months. In the Mayo Clinic series of 25 patients with primary PCL, 7 of 15 patients responded to melphalan with or without prednisone. Despite the response rate of 47%, the median time to progression or death in these 15

patients was 8.7 months. The median duration of survival for all 25 patients with PCL was 6.8 months, and only 4 patients survived for more than 2 years.

The overall response rate in the series by Dimopoulos et al.40 was 37%. They noted that failure to achieve 50% clearing of peripheral blood plasma cells within 10 days after initiation of treatment was a predictor of no response. The median duration of survival was 12 months. A short survival was caused mainly by the large number of patients dying of disease complications during the first 2 months of treatment. In that series, patients treated with vincristine, doxorubicin (adriamycin), and dexamethasone (VAD) or with cyclophosphamide and etoposide had a response rate of 59% and a median duration of survival of 20 months. These improved results are probably due to a decrease in early mortality as a result of a rapid reduction of tumor mass, and due to improved supportive therapy. Garcia-Sanz et al.28 reported an overall response rate of 38%. The response rate and survival were lower in patients treated with melphalan and prednisone than in those given alternating courses of vincristine, cyclophosphamide, melphalan, and prednisone (VCMP) or vincristine, 1,3-bis(2-chlorethyl)-1-nitrosourea (BCNU), doxorubicin (adri-amycin), and prednisone (VBAP).

Treatment with a single alkylating agent plus prednisone is not adequate for patients with primary PCL. Combination chemotherapy with VAD, cyclophosphamide, and etoposide or alternating VCMP and VBAP yields better responses. High-dose therapy followed by autologous stem cell transplantation should be offered to responding patients if age and clinical condition do not preclude transplanta-tion.43 Thalidomide also may be a useful agent.44

Secondary PCL usually is a terminal event in patients with relapsed or refractory myeloma. Unfortunately, the median duration of survival in these patients is about 1 month.27 Thalidomide may be of some benefit in this situation.45

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