Sinusoidal obstruction syndrome or veno-occlusive disease (SOS/VOD) is a potentially life-threatening complication of hematopoietic SCT (HSCT). This review aims to highlight, on behalf of the European Society for Blood and Marrow Transplantation, the current knowledge on SOS/VOD pathophysiology, risk factors, diagnosis and treatments. Our perspectives on SOS/VOD are (i) to accurately identify its risk factors; (ii) to define new criteria for its diagnosis; (iii) to search for SOS/VOD biomarkers and (iv) to propose prospective studies evaluating SOS/VOD prevention and treatment in adults and children.

A randomized trial of 12.0 Gy versus 15.75 Gy of total body irradiation (TBI) was performed in patients with acute myeloid leukemia undergoing allogeneic marrow transplantation while in first complete remission. All patients received 120 mg/kg cyclophosphamide followed by TBI and marrow from HLA-identical siblings. Cyclosporine and methotrexate were used for prophylaxis against acute graft-versus-host disease (GVHD). Thirty-four patients received 2.0-Gy fractions of irradiation daily for 6 days and 37 received 2.25-Gy fractions daily for 7 days. The 3-year actuarial probabilities for relapse-free survival were 0.58 for the patients who received 12.0 Gy and 0.59 for those who received 15.75 Gy. The 3-year probabilities of relapse were 0.35 for the 12.0 Gy group and 0.12 for the 15.75 Gy group (P = .06). The 3-year probabilities of transplant-related mortality were 0.12 and 0.32, respectively (P = .04). The probability of moderate to severe acute GVHD was 0.21 for the 12.0 Gy group and 0.48 for the 15.75 Gy group (P = .02). Patients exposed to the higher irradiation dose received less immunoprophylaxis against, and had a higher incidence of, acute GVHD. The increased dose of TBI significantly reduced the probability of relapse but did not improve survival because of increased mortality from causes other than relapse.

Between October 1979 and January 1988, 101 patients with malignant lymphoma who failed initial induction treatment or relapsed received high-dose combination chemotherapy or chemoradiotherapy followed by infusion of autologous bone marrow. Twenty-eight of the 101 patients survive, 18 of whom are disease-free for a median of 26 (range, 12 to 66) months. The 5-year actuarial probabilities of survival, event-free survival (EFS), and relapse from transplantation were 20%, 11%, and 84%, respectively. Multivariate analysis showed that the likelihood of EFS was decreased among patients transplanted with a Karnofsky score of less than 80%. Recurrent lymphoma after transplant was the most important cause of treatment failure with 36 of 62 relapses occurring within 100 days from marrow infusion. Early, but not late relapse, was more frequent in patients transplanted for advanced lymphoma, and both early and late relapses were increased among patients with impaired pretransplant clinical performance or high-grade histology of lymphoma. Ten patients who relapsed post-transplant are alive, seven in remission. Further improvement of these results will require earlier transplantation, improved preparative regimens, or early posttransplant therapy.