This study is for adults who have Small Cell Lung Cancer (SCLC) and have already received treatment. With this type of cancer, it is quite common for it to spread to the brain. To reduce this risk, some patients are offered a type of preventative brain radiotherapy called prophylactic cranial irradiation (PCI).

However, PCI can cause side effects, so this study is looking at a different approach: active surveillance. This means monitoring the brain regularly using MRI scans instead of giving radiation straight away.

The aim of the study is to find out whether regular MRI monitoring is just as effective for survival as PCI, while also causing fewer side effects.

The study will take place in NHS hospitals across the UK and is part of a larger international research project. It is sponsored and coordinated by the EORTC (European Organisation for Research and Treatment of Cancer), a non‑profit organisation based in Brussels.