Stage III non-small cell lung cancer (NSCLC) patients constitute a significant proportion of the lung cancer population. The prognosis of these patients has improved over the years due the introduction of combined modality treatment, including high-dose chemo-radiotherapy. The brain, however, remains one of the major sites of failure. Patients with brain metastasis suffer from a variety of neurological, cognitive and emotional difficulties that are known to adversely affect the health-related quality of life. Prophylactic Cranial Irradiation (PCI) can prevent or delay the development of brain metastasis, and as such can improve neurological disease-free survival and consequently health-related quality of life. But survival is short, and toxicities are real, as PCI in itself can also induce adverse effects. The cognitive adverse effects of PCI are not sufficiently illuminated and documented, due to the lack of formal and systematic evaluation in patient populations expected to have short survival. Also, recent attempts to reduce cognitive side effects of PCI by the application of hippocampal-avoidance PCI in order to prevent memory deficits have not been fully evaluated yet.

Before PCI can be offered routinely to stage III NSCLC patients in daily practice, the costs and benefits of this therapy should be investigated properly, to allow for well-informed treatment choices.

Inclusion Criteria:

• UICC stage III A or III B (without malignant pleural or pericardial effusion) non-small cell lung cancer
• Whole body PDG-PET scan before the start of therapy available: no distant metastasis.
• CT or preferably MRI of the brain before the start of radical therapy available; no brain metastasis.
• Platinum-based chemotherapy is mandatory.
• Radical local therapy: concurrent or sequential chemotherapy and radiotherapy with or without surgery.
• Radiotherapy dose without surgery to at least biological equivalent of 60 Gy.
• No prior cranial irradiation.sufficient proficiency in Dutch language
• sufficient proficiency in Dutch language
• MRI (and not CT scan) pre-PCI

Exclusion Criteria:

• none

Patients will be recruited from 5 hospitals participating in the phase III trial: Prophylactic Cranial Irradiation (PCI) versus observation in radically treated patients with stage III non-small lung cancer: a phase III randomized study ((NVALT 11/DLCRG-02).