***TASK***
the task is to simplify the input abstract of a biomedical literature

***INPUT***
the input is the abstract of a biomedical literature

***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature

***DOCUMENTATION***

***EXAMPLES***

Input: No additional studies were identified in this 2015 review update, in total leading to no studies meeting the criteria for inclusion in this review. The efficacy of ECP in the treatment of chronic GvHD in paediatric patients after haematopoietic stem cell transplantation based on RCTs cannot be evaluated since the original version of this review and the first review update found no RCTs. Current recommendations are based on retrospective or observational studies only. Thus, ideally, ECP should be applied in the context of controlled trials only. However, performing RCTs in this patient population will be challenging due to the limited number of patients, the variable disease presentation and the lack of well-defined response criteria. International collaboration, multicentre trials and appropriate funding for such trials will be needed. If treatment decisions based on clinical data are made in favour of ECP, patients should be carefully monitored for beneficial and harmful effects. In addition, efforts should be made to share this information with other clinicians, for example by setting up registries for paediatric patients that are treated with ECP.
Output:

We searched scientific databases for randomised controlled trials (clinical studies where people are randomly put into one of two or more treatment groups) that were designed to evaluate the effectiveness and safety of ECP for the management of chronic graft-versus-host disease in children and adolescents (under 18 years of age) after HSCT. The original version of this review and this 2015 review update found no RCTs that analysed the efficacy of ECP for paediatric patients with chronic graft-versus-host disease after HSCT. Current recommendations are based on retrospective (a study in which the outcomes have occurred to the participants before the study began) or observational (a study in which the investigators do not seek to intervene, and simply observed the course of events) studies only. Thus, ideally, ECP should be applied in paediatric patients in the context of RCTs only. ECP may be considered in people with steroid-refractory chronic GvHD, keeping in mind that such a treatment is not supported by high-level evidence. If treatment decisions based on clinical data in favour of ECP are made, patients should be carefully monitored for beneficial and harmful effects and efforts should be made to share this information with other clinicians, for example by setting up registries for paediatric patients that are treated with ECP.