PulmoPrint is a clinical study at UMCG that investigates why some patients with unresectable stage III lung cancer stop responding to immunotherapy after chemoradiation. To do this, a small dose of a fluorescently labeled version of the immunotherapy drug durvalumab is given via an IV drip, after which a camera bronchoscopy is performed to visualize where and how much of the drug actually reaches the tumor and lymph nodes - before the actual durvalumab treatment starts.

Inclusion Criteria:

• Signed informed consent prior to participation in the study.
• Age ≥ 18 years.
• Histologically or cytologically confirmed unresectable stage III NSCLC.
• Completion of concurrent platinum-based CRT
• Eligibility for adjuvant durvalumab per standard of care.
• At least one tumor lesion or involved lymph node accessible by bronchoscopy or endoscop-ic/endobronchial ultrasound, suitable for biopsy/FNA and fluorescence measurement.
• ECOG performance status 0-2.
• Patient is considered fit to undergo a research bronchoscopy (with or without addition of endobronchial ultrasound; including propofol sedation or general anesthesia if either is indicated).

Exclusion Criteria:

• Known history of infusion reactions to durvalumab, other anti-PD-L1 antibodies, or other monoclonal antibodies, according to the patient's medical history.
• Contraindication for bronchoscopy or endoscopic/endobronchial ultrasound (if applicable), including severe uncorrectable coagulopathy, pre-existing severe respiratory insufficiency, or any other clinical reason as judged by the investigator.
• Medical or psychiatric conditions compromising the patient's ability to provide informed consent, according to the treating physician.
• Pregnancy or breastfeeding. A negative pregnancy test must be available for women of childbearing potential on the day of tracer administration.
• Use of an investigational medicinal product within 30 days prior to tracer administration.