Nationwide survey of BK polyomavirus associated hemorrhagic cystitis in adult allogeneic stem cell transplantation among haematologists and urologists.

There are no epidemiological data on BK virus associated hemorrhagic cystitis (BKHC) in adult allogeneic stem cell transplantation in Germany available and associations with clinical conditions like GvHD are controversially discussed. Therefore, we conducted a nationwide survey among haematologists and urologists about this disease. We developed two questionnaires, one for haematologists (26 items) and one for urologists (20 items) concerning BKHC in adult allogeneic stem cell transplantation with epidemiological data and clinical implications. The survey was sent out at least three times to EBMT registered centres performing at least five transplantations a year, leading to 39 centres. The recruiting time was between January and June 2016. Total response rates were 76.9% among haematologists and 74.4% among urologists. BKHC seems to appear less frequent in this survey than it is described in the literature. Six deaths in the last 5 years due to this disease have been reported. Interestingly, haematologists as well as urologists mostly think that local therapy is most effective while 50.0% stated that there is no real effective oral or intravenous medication. Associations with other clinical conditions mentioned were heterogeneous, e.g. transplantation type, CMV reactivation, acute GvHD, nephropathy and worse clinical outcome. There was a significant discrepancy between haematologists and urologist concerning the association with acute GvHD (p = 0.004). We need prospective, multicentric clinical studies to evaluate local therapy and for developing a risk stratification model since this disease can be severe with morbidity and rarely mortality. In our opinion, this should be an interdisciplinary approach.