The study is a prospective, non-randomized, cohort study of patients with pleural effusion. Participants will be recruited from patients referred to the Pleura Clinic or admitted at the ward at the Department of Respiratory Medicine, Næstved Hospital, Næstved or at the Department of Respiratory Medicine, Zealand University Hospital, Roskilde, which is the two regional centres for workup of pleural effusions. Patients will be referred from either general practice or other hospital departments.
Pleural fluids with cytology positive for NSCLC will be tested for oncodrivers (for squamous cell carcinomas (SCC): PD-L1, for adenocarcinomas (AC): PD-L1, ALK and EGFR).
Follow-up will be 8 weeks after inclusion.
