Predictive factors and treatment outcomes of tuberculous pleural effusion in cancer patients with pleural effusion Short title : Cancer patients with tuberculous pleural effusion

Objectives: Patients with cancer are at increased risk of tuberculosis. As pleural effusion has great clinical significance in patients with cancer, the differential diagnosis between tuberculous pleural effusion (TPE) and malignant pleural effusion (MPE) is important. However, the predictive factors and treatment outcomes of TPE in cancer patients have rarely been studied. Methods: Confirmed TPE cases identified at cancer diagnosis and during anti-cancer management from 2008 to 2015 were retrospectively investigated. Control groups were MPE patients, and TPE patients without cancer. Clinical, laboratory, and pleural fluid characteristics were compared among groups. Treatment outcomes were compared between TPE patients with and without cancer. Results: Patients in the study included coexisting TPE and cancer (n=20), MPE (n=40), and TPE without cancer (n=40). In the final analysis, serum C-reactive protein (S-CRP) ≥3.0 mg/dL and pleural fluid adenosine deaminase (ADA) ≥40 U/L were independent predictors for identifying TPE in cancer patients with pleural effusion. The combination of S-CRP with