Superior survival in primary systemic amyloidosis patients undergoing peripheral blood stem cell transplant: A case control study

Primary systemic amyloidosis (AL) is a plasma cell dyscrasia resulting in multisystem failure and death. High dose chemotherapy with peripheral blood stem cell transplant (PBSCT) has been associated with higher response rates and seemingly higher overall survival than standard chemotherapy. Selection bias, however, confounds interpretation of these results. We performed a case match control study comparing overall survival of 63 transplanted AL patients to 63 non-transplanted patients. Matching criteria included age, gender, time to presentation, left ventricular ejection fraction, serum creatinine, septal thickness, nerve involvement, 24 hour urine protein, and serum alkaline phosphatase. According to design, there was no difference between the groups with respect to gender (57% males), age (median 53 years), left ventricular ejection fraction (65%), number of patients with peripheral nerve involvement (17%), cardiac interventricular septal wall thickness (12 mm), serum creatinine (1.1 mg/dL), and bone marrow plasmacytosis (8%). Sixty-six patients have died (16 cases and 50 controls). For PBSCT and control groups respectively, the 1, 2, and 4 year overall survival rates are: 89 and 71%; 81 and 55%; and 71 and 41%. Outside a randomized clinical trial, these results present the strongest data supporting the role of PBSCT in selected patients with AL. Supported in part by CA 62242(R.A.K), CA 91561(A.D) from the National Cancer Institute, and the Robert A. Kyle Hematology Malignancies Fund, Mayo Foundation.