This is an interesting problem. Assuming the pathologist reports this as "large cell neuroendocrine", essentially this is a non-small cell lung carcinoma and we treat as such recognising the significant concern for brain metastasis. We do not do PCI for these patients and a pre-treatment MRI brain i...

I would get the pathology reviewed at a large center to make sure this is not a pulmonary neuroendocrine tumor (typical or atypical) carcinoid. The management would be different, as would imaging, the role of XRT, and selection of technique/volume/dose, etc.