Outcome of African-American (AA) Multiple Myeloma (MM) Patients after Autologous Stem Cell Transplantation (ASCT): A Single-Center Experience.

The incidence of MM in African-Americans is more than double that in Caucasians. Historically AAs have had a higher mortality rate than Caucasians; but over the past 10 yrs, the age-adjusted mortality rate has been on the decline for AAs while it has been stable for Caucasians as a result of ASCT and novel agents. Previous studies (n=74 AA patients) suggested that response to ASCT is similar, if not better, for AA patients (Verma et al 2008, Saraf et al 2006). We retrospectively analyzed the clinical presentation of a large cohort of AA patients (n=103) who underwent ASCT at our center between 1998 and 2008 and compared their outcome to that of Caucasians patients (n=183) transplanted in the same time period. AA patients were significantly younger than Caucasian patients at diagnosis with median age 53 (range: 32–75) vs 59 (range: 27–80), respectively (p<0.0001). The distribution of isotype and stage of MM at diagnosis were similar between the two groups. Approximately 20% patients in each group presented with renal insufficiency. Among the AA patients, 45% had albumin < 3.5 g/dL; 14% and 18% had beta2-microglobulin > 3.5 mg/L and > 5.5 mg/L, respectively. Initial cytogenetic data were not available for the majority of patients. Median time from diagnosis to ASCT was significantly longer for AA than for Caucasian patients at 0.8 yrs (range: 0.23–9.2) vs 0.5 yrs (range: 0.1– 7.0), respectively (p<0.0001). There was no difference in incidence of transplant-related complications, as reflected by similar lengths of hospital stay, with a median of 15 days for both groups. No significant difference in response to ASCT was found between the two groups. Median EFS was 1.7 yrs (range: 1.5–2.7) for AAs and 1.8 yrs (range: 1.5–2.4) for Caucasians (p=NS). At a median follow up of 5 yrs, 74% of AA and 70% of Caucasian patients were alive. Median OS was also not significantly different at 9 yrs (range: 6.7- not reached) for AAs and 8 yrs (range: 5.9-not reached) for Caucasians (p=NS). Cox regression model for prognostic markers: albumin, calcium, creatinine, hemoglobin, and platelet count were significant for OS in AA patients (p range 0.004–0.0001). The current study is the largest one of AA patients undergoing SCT at a single institution. AA patients with MM present at a younger age, but undergo ASCT at a significantly later time from diagnosis than Caucasian patients. This delay may reflect a disparity in referral pattern and access to health care. AA patients have similar EFS and OS after ASCT. It is likely that better responses to the newer anti-myeloma agents, as well as favorable impact of ASCT, even if delayed, may explain the improvement of AA patients with MM over the past decade. Further studies of responses of AA patients to novel myeloma agents are needed.