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Background:As more patients are treated by haematopoietic stem cell transplantation (HSCT), development of secondary malignancy (SM) becomes an increasingly common issue in long-term survivors.Methods:We conducted a nationwide population-based study of the Taiwanese population to analyse patients who received HSCT between January 1997 and December 2010. Standardised incidence ratios (SIRs) were used to compare the risk of SM in HSCT patients and the general population. Multivariate analysis was performed to identify independent predictors of SM.Results:Patients receiving HSCT had a significantly greater risk of developing SM (SIR 2.00; 95% confidence interval (CI) 1.45–2.69; P<0.001). Specifically, the incidence increased for cancers of the oral cavity (SIR 14.18) and oesophagus (SIR 14.75) after allogeneic HSCT. Multivariate analysis revealed an increased SIR for cancer in patients who received the immunosuppressant azathioprine. The risk of SM also increased with greater cumulative doses of azathioprine.Conclusions:This study demonstrates an increased incidence of SM in Taiwanese patients who received allogeneic HSCT, especially for cancers of the oral cavity and oesophagus. This finding is different from results in populations of Western countries. Physicians should be cautious about azathioprine use for graft-vs-host disease after HSCT.

In Taiwan, hematopoietic SCT (HSCT) has been used to treat patients with hematological diseases since 1983. Since then, more than 2200 patients have undergone HSCT in 15 large hospitals. The disease entities included acute leukemia in 37% of cases, non-Hodgkin's lymphoma in 26%, CML in 10%, multiple myeloma in 7% and severe aplastic anemia in 6%. The conditioning regimens used were mainly myeloablative (84% of cases). Nonmyeloablative regimens were fludarabine-based. The average age of allogeneic recipients was at least 10 years older than those in the era before their application. The grafts of all patients were derived from peripheral blood in 85% of cases, BM in 13% and cord blood (CB) in 2%. Forty percent of HSCT patients received autologous grafts, whereas more than 25% of allogeneic HSCT patients received grafts from unrelated donors, and overall, there were more than 200 Taiwan HSCT recipients. Currently, CB has been used successfully in pediatric patients with thalassemia major and also in adult patients with hematological malignancy. After transplantation, there was a relatively lower prevalence of acute GVHD. However, a relatively higher proportion of hepatitis B carriers in the recipients had led to a higher incidence of viral reactivation and clinical hepatitis, which was dramatically decreased following lamivudine prophylaxis. In conclusion, HSCT has been successfully adapted to routine clinical care in Taiwan. Several important findings contributing to the progress of HSCT in the past two decades have also been noticed on this island.

Summary:We report a nonmyeloablative allogeneic bone marrow transplant (allo-BMT) from an HLA-matched unrelated donor in a case of acute myeloid leukemia (AML), M2 with t(8;21)(q22;q22) and the presence of orbital granulocytic sarcoma (GS), who had residual tumor after conventional chemotherapy. The course of BMT was well tolerated, with no major procedure-related toxicity. The residual orbital GS regressed completely 4 months after BMT. She is currently 19 months post BMT, diseasefree. To our knowledge, this is the first reported pediatric patient with AML, GS and t(8;21)(q22;q22) who received a nonmyeloablative allo-BMT.

In non-endemic areas, such as Taiwan, ATL, particularly the non-acute type, may mimic other lymphomas and easily be misdiagnosed. HTLV-1 serology should be routinely screened in all malignant lymphoma patients. In situ detection of HTLV-1 is helpful in cases with diagnostic dilemmas.