The Belgian experience in unrelated donor bone marrow transplantation: identification of center experience as an important prognostic factor

Background and Objective. We reviewed all unrelated donor bone marrow trans plants (UDBMT) performed in Belgium up to December 1995 to identify prognos tic factors for relapse, transplant-related mortality and survival. Design and Methods. A total of 163 UDBMT were performed in 92 males and 71 females aged 1-55 (median 26) years. Patients were transplanted for ALL (n= 35), AML (n=34), CML (n=51), other myeloid malignancies (n=14), SAA (n=21) or miscellaneous other diseases (n=8). Most patients had advanced disease; a few patients were in CR1 (n=10) or early chronic phase (CP) of CML (n=5). Results. overall survival at 5 yrs was 17% (95% confidence interval: 8-32%) , but survival was significantly better for patients with non-malignant dis orders (55% at 4 yrs). The relapse rate +/-SE was projected to be 40 (28-54 )% at 5 yrs, 36 (20-56)% for standard-risk and 68 (43-85)% for high-risk ma lignancies (p=0.0029). There was no relapse in CML patients transplanted in Ist CP compared to 68% at 4 yrs with more advanced CML (p=0.0033). Grade I i-IV acute graft-versus-host disease (aGVHD) occurred in 55% by day 100 aci d was strongly modulated by age, ranging from 41% in <20-yr-old to 80% in > 40-yr-old patients (p=0.0021). Transplant-related mortality (TRM) was proje cted to be 72 (52-87)% at 5 yrs including 2 very late deaths from lung fibr osis and secondary cancer. Main causes of death were original disease in 27 , secondary malignancy in 2, GVHD in 28, interstitial pneumonia in 21, othe r infections in 19, and miscellaneous toxic causes in 21 patients. In multi variate analysis, the relapse rate was strongly dependent on the disease st atus (p=0.0029), TRM being significantly worse with older age (p=0.0049), a nd overall survival being significantly worse in more advanced disease (p=0 .0006), after a second transplant (p=0.0166), in centers of smaller size (p =0.0316) and in older patients (NS). Interpretation and Conclusions. Although results have improved somewhat in recent years, UDBMT remains a procedure with a high TRM. UDBMT should be pe rformed in patients with less advanced diseases and in centers with more ex perience, particularly in the treatment of adult patients. (C) 1999, Ferrat a Storti Foundation.