Tandem versus single autologous hematopoietic cell transplantation for the treatment of multiple myeloma: a systematic review and meta-analysis.

BACKGROUND Evidence bearing on the efficacy of tandem autologous hematopoietic transplant (AHCT) vs a single AHCT in patients with multiple myeloma (MM) is conflicting. We performed a systematic review and meta-analysis to synthesize the existing evidence related to the effectiveness of tandem vs single AHCT in patients with MM. METHODS We searched Medline, conference proceedings, and bibliographies of retrieved articles and contacted experts in the field to identify randomized controlled trials (RCTs) reported in any language that compared tandem with single AHCT in patients with MM through March 31, 2008. Endpoints were overall survival (OS), event-free survival (EFS), response rate, and treatment-related mortality (TRM). Data were pooled under a random-effects model. RESULTS Six RCTs enrolling 1803 patients met the inclusion criteria. Patients treated with tandem AHCT did not have better OS (hazard ratio [HR] for mortality for patients treated with tandem transplant vs single transplant = 0.94; 95% confidence interval [CI] = 0.77 to 1.14) or EFS (HR = 0.86; 95% CI = 0.70 to 1.05). Response rate was statistically significantly better with tandem AHCT (risk ratio = 0.79, 95% CI = 0.67 to 0.93), but with a statistically significant increase in TRM (risk ratio = 1.71, 95% CI = 1.05 to 2.79). There was statistically significant heterogeneity among RCTs for OS and EFS. CONCLUSION In previously untreated MM patients, use of tandem AHCT did not result in improved OS or EFS. We conclude that tandem AHCT is associated with improved response rates but at risk of clinically significant increase in TRM.