Natural History of Relapse after Autologous Stem Cell Transplantation for Multiple Myeloma.

Although autologous stem cell transplantation (APBSCT) is known to prolong survival of patients with myeloma, most patients relapse after transplantation. How treatment of patients who relapse after transplantation affects survival is not clear. At our institution, of 83 patients transplanted for myeloma from 1996–2005, we identified 25 patients who relapsed and had adequate records for analysis. The relapse cohort consisted of 15 single APBSCT and 10 tandem APBSCT recipients. Twenty patients were Stage III at time of original diagnosis, 3 patients were Stage II, and 3 were Stage I with 15 patients being IgG-kappa, 3 patients IgA-kappa, 2 patients IgG-lambda and 1 patients IgA-lambda. Two patients had non-secretory disease and 2 had light-chain only myeloma. Best response achieved after transplant included 5 complete responses (CR), 14 partial responses (PR), one stable disease (SD), 3 minimal responses (MR), and 2 with progressive disease (PD). Maintenance therapy consisting of interferon-alfa, pulse-dosed or every-other-day steroids, and thalidomide with or without steroids was documented in 12 patients. Of the relapsed cohort, 19 went on to receive further treatment consisting of radiation therapy (2), dexamethasone-based chemotherapy [bortezomib, another induction regimen, thalidomide] (15) or another transplant (2). The median duration of response for the relapse cohort was 372 days (76–1661 days). Median survival from relapse is 304 days (range 19–1155 days). There was a trend for a correlation between duration of initial response and survival after relapse (p=0.08), but no correlation with survival after relapse and best response to APBSCT (p=0.63), use of maintenance posttransplant (0.27) or treatment of relapse (0.17). The small number of patients may have limited the power of our study to detect significant associations in our cohort. We conclude that patients who relapse after APBSCT can have a prolonged survival, and those with the longest initial duration of response have the best outcome, but the optimal approach to salvage for these patients is not clear.