S103 Baseline CT thorax in patients undergoing allogeneic haematopoetic stem-cell transplantation and risk of invasive fungal disease- a prospective 5-year study

Invasive fungal lung disease (IFD) is a well-recognised complication post haematopoietic stem-cell transplant (HSCT), occurring in approximately 5–21% of patients, despite tri-azole anti-fungal prophylaxis. Baseline CT thorax (BCT) pre-HSCT is increasingly considered as standard practise to evaluate lung disease, however evidence on outcomes from previous studies has been limited by either small or heterogenous cohorts (Ceesay et al 2018, Bitterman et al 2019). Kings College Hospital is one of the largest HSCT centres in the UK, as such IFD accounts for a significant patient morbidity and hospital bed days. We conducted a single centre prospective analysis of patients with myeloid malignancies and aplastic anaemia (n=350) who underwent T-cell deplete allo-HSCT between Jan 2015 and April 2019. BCT was performed in 235 patients. IFD was defined by by EORTC criteria. See figure 1 for baseline characteristics. Post HSCT, IFD developed in 9.1% of total patients (n=32/350) and in 12.3% (n=29/235) of those who had BCT. Patients with European Platform of Cancer Research (EORTC) defined changes on BCT developed significantly more IFD (34.2% vs 9.4%, p=0.0004). Univariate analysis of baseline characteristics identified that a significantly higher proportion of those with pre-HSCT IFD developed post-HSCT IFD (33.3% vs 8.3%; P=0.003). Reduced intensity conditioning, poor baseline performance status and co-morbidities, and gas transfer (TLCO Abnormal BCT did not influence overall survival, however in patients with EORTC defined changes on BCT, there was a significant reduction in median IFD-free survival (30.5 months vs 47 months, p=0.009) when compared to non-EORTC and normal CT findings. There was a significant reduction in overall survival at 12 months post HSCT in those who developed IFD (62% vs 76%, p=0.001, log rank). Previous IFD, EORTC BCT changes and abnormal TLCO pre-HSCT influence IFD related outcomes and we suggest early respiratory optimisation pre-HSCT to reduce risk of IFD-related mortality. Further evaluation of impact of interventions in patients with abnormal BCT is warranted.