Kyle, RA

The plasma cell labeling index (LI) is of value in predicting prognosis in multiple myeloma. Primary systemic amyloidosis (AL) is a plasma cell dyscrasia that shares many features with myeloma. We obtained bromodeoxyuridine LI on 125 patients who presented with AL, 22 of whom also had overt multiple myeloma. Forty-six patients had a plasma cell LI greater than 0%. Of the 46 patients with an elevated LI, 19 (41%) had multiple myeloma as compared with three (4%) of the 79 patients with an LI = 0 (P less than .0001). A response to chemotherapy was seen in 14 (30%) of 46 patients with an LI greater than 0, as compared with ten (13%) of 79 patients with an LI of 0 (P = .015). The median survival of the high LI group was 14.6 months v 29.8 months for the low LI group (P = .02). In the low LI group, 29% are projected to be alive at 60 months, as compared with 20% in the high LI group. When patients with myeloma were excluded from the analysis, the LI did not predict response but continued to indicate a survival disadvantage (P less than .05). The major utility of the LI was in identifying those patients most likely to have multiple myeloma and those AL patients with a poor prognosis (median survival, 14.1 months).

Patients (153) with biopsy-proven primary systemic amyloidosis (AL) were evaluated for their response rate to alkylating agent-based chemotherapy. Twenty-seven of the patients (18%) responded. The serum creatinine concentration had an adverse effect on response rate (P = .05). In patients with nephrotic syndrome, a normal serum creatinine value, and no echocardiographic evidence of cardiac amyloidosis, the response rate was 39% (12 of 31). Five of 34 patients with amyloid cardiomyopathy responded. Two of these five are alive 10 years after diagnosis. None of the 18 patients with amyloid peripheral neuropathy showed regression of their disease. The median time to achieve response was 11.7 months. The median survival of the 27 patients was 89.4 months and 21 of 27 survived 5 years (78%). Eight patients remain alive with a minimum follow-up of 90 months. Seven died of acute leukemia or dysmyelopoietic syndrome, a presumed complication of melphalan therapy. In the group of 126 patients who showed no response to alkylating agent- based therapy, the median survival was 14.7 months and 9 (7%) survived over 5 years. All 126 patients have died. Alkylating agent-based chemotherapy for AL is beneficial in a subset of patients and a trial of chemotherapy is strongly recommended. Those patients who do respond demonstrate survival benefit.