2863 - Long-Term Survival and Associated Idiopathic Pneumonia Syndrome (IPS) Outcomes Following Total Body Irradiation (TBI)-Conditioned Hematopoietic Stem Cell Transplantation (HSCT) for Acute Leukemia
Presenter(s)
S. N. Shah1, T. E. DeFor2, E. Ehler3, R. W. Gao4, K. E. Dusenbery3, S. A. Terezakis3, and C. Rodriguez-Russo5; 1Department of Radiation Oncology, University of Minnesota, Minneapolis, MN, 2Clinical and Translational Science Institute, University of Minnesota, Minneapolis, MN, 3Department of Radiation Oncology, University of Minnesota Medical School, Minneapolis, MN, 4Department of Radiation Oncology, Mayo Clinic, Rochester, MN, 5University of Minnesota, Minneapolis, MN
Purpose/Objective(s): IPS is a known complication of HSCT, but its relationship with long-term survival is poorly defined. We aimed to evaluate long-term survival outcomes and evaluate the incidence and survival impact of IPS in a large cohort of patients with acute leukemia undergoing HSCT with a uniform TBI-based conditioning regimen.
Materials/Methods: This study included a cohort of all 202 patients with acute leukemia (55% ALL and 45% AML) who initially underwent HSCT at a single institution between 2006 and 2016 and were included in a prospective registry. Pretransplant conditioning consisted of cyclophosphamide with fludarabine in 69% of patients and cyclophosphamide alone in 31%. All patients received TBI to a total dose of 13.2 Gy delivered in 8 fractions twice daily using parallel opposed lateral fields. IPS was defined according to the American Thoracic Society criteria after the development of clinical and radiographic findings consistent with IPS within 100 days of transplant. Overall survival (OS) was estimated using Kaplan–Meier curves with 95% confidence interval. The time-dependent effect of IPS on OS was evaluated with Cox regression.
Results: Among 202 patients, the median age was 25 years, and 57% were male. The median follow-up after transplantation was 73 months. 45% of the patients had prior pulmonary disease. 42 (21%) developed IPS, with a median onset of 16 days post-transplant. The 1-, 3-, 5-, and 10-year OS rates following HSCT were 67% (95% CI, 61–74%), 57% (50–64%), 56% (49–63%), and 52% (46–60%), respectively.
The estimates of IPS-related mortality and non-IPS-related mortality at 1, 3, 5, and 10 years were 9%, 9%, 9% and 11%; vs. 24%, 33%, 35%, and 37%, respectively. Compared with patients without IPS, those with IPS did not have significantly different all-cause mortality (HR = 1.3; 95% CI, 0.8–2.2; p = 0.26).Conclusion: At 10-year follow-up, while a subset of patients developed IPS associated with TBI-conditioned HSCT, there was no statistically significant difference in 10-year mortality between patients with and without IPS, and deaths from IPS represented a small share of total mortality. We conclude that in a large cohort of patients with acute leukemia, patients with TBI-HSCT associated IPS did not have statistically inferior overall survival relative to those without IPS.