Relative survival of long-term hematopoietic cell transplant recipients approaches general population rates

Abstract

Whether the annual mortality rates of long-term hematopoietic cell transplant (HCT) survivors ever return to that of the general population is unclear. This study sought to determine the annual long-term mortality rates of allogeneic and autologous HCT recipients who had survived 5 years or more disease-free posttransplant and calculate their relative survival rates. Patients were included if they had a first allogeneic or syngeneic HCT for acute leukemia, chronic myelogenous leukemia (CML) or myelodysplastic syndromes (MDS), or autologous HCT for acute myelogenous leukemia (AML) or lymphoma in Australia or New Zealand between 1992 and 2001, recorded on the Australasian Bone Marrow Transplant Recipient Registry (ABMTRR) database, and were known to have survived, disease free, 5 years or more posttransplant. The annual mortality rates of 5-year transplant survivors were compared to standard Australian and New Zealand populations using relative survival. A total of 1461 HCT survivors (688 postallograft, 773 postautograft) were included in this study. The 10-year survival probability for 5-year allograft survivors was slightly higher than that of 5-year autologous survivors (93.4% versus 89.6%, P=.06). The relative survival of both allogeneic and autologous 5-year survivors was never <97% of that of the general population. However, it was statistically significantly lower than expected in the sixth to ninth years posttransplant, with no obvious pattern of either improvement or deterioration from 6 to 10 years posttransplant. This study indicates that annual relative survival rates of long-term survivors of allogeneic HCT performed in Australia and New Zealand for acute lymophoblastic leukemkia (ALL), AML, CML, and MDS are slightly, but significantly lower than population rates in the 6th to 10th years posttransplant. Annual relative survival rates of long-term survivors of autologous HCT performed in Australia and New Zealand for AML and lymphomas are also slightly lower than population rates up to the 10th year posttransplant. Late deaths from transplant and disease-related causes are unusual, but continue to occur for many years post-HCT.