Natural History of Nonspecific Pleuritis Diagnosed After Video-assisted-thoracoscopic-surgery

Using Landspatientregisteret (LPR) (the National Patient register) the investigators will identify patients who have received a thoracoscopic pleural-biopsy using the SKS-codes KGAC01 and/or KGAA31 and/or KGAC00. From LPR and Cancerregisteret (the National Cancer-register) the investigators will receive diagnosis and additional descriptive data. From dødsårsagsregisteret (the National cause-of-death-register) death date and further descriptive data will be acquired.

Patients with NSP will be identified as patients with no diagnosis six months after pleural-biopsy, despite a thorough investigation.

Patients with a malignant effusion and non-malignant effusion (with known cause) will be used for survival analysis and comparison.

Data Data will be registered in the individual patients CRF (Case Report File) (digital) and will be transferred to a database-program for further processing. Background-variables will be used to describe the study population. Only study-coordinators will have access to data. All data including back-up will be stored and kept in a locked cupboard in a locked room. Only study coordinators possess relevant keys.

Statistics The investigators define significance level (α) as 0.05, and power (β) as 0.80. Descriptive data will be analysed using nonparametric statistics: Chi2-test for categorical data and Mann-Whitney for discrete data. Statistical significance is defined as: p-value < 0.05.