title: Minimal Pleural Effusion in Small Cell Lung Cancer: Proportion, Mechanisms, and Prognostic Effect.
abstract: OBJECTIVE
  To determine the frequency and investigate possible mechanisms and prognostic relevance of minimal (<10-mm thickness) pleural effusion in patients with small cell lung cancer (SCLC).
  
  
  METHODS
  The single-center retrospective study was approved by the institutional review board of the hospital, and informed consent was waived by the patients. A cohort of 360 consecutive patients diagnosed with SCLC by using histologic analysis was enrolled in this study. Based on the status of pleural effusion on chest computed tomographic (CT) scans at diagnosis, patients were classified into three groups: no pleural effusion, minimal pleural effusion, and malignant pleural effusion. Eighteen variables related to patient, environment, stage, and treatment were included in the final model as potential confounders.
  
  
  RESULTS
  Minimal pleural effusion was present in 74 patients (20.6%) and malignant pleural effusion in 83 patients (23.0%). Median survival was significantly different in patients with no, minimal, or malignant pleural effusion (median survival, 11.2, 5.93, and 4.83 months, respectively; P < .001, log-rank test). In the fully adjusted final model, patients with minimal pleural effusion had a significantly increased risk of death compared with those with no pleural effusion (adjusted hazard ratio, 1.454 [95% confidence interval: 1.012, 2.090]; P = .001). The prognostic effect was significant in patients with stage I-III disease (adjusted hazard ratio, 2.751 [95% confidence interval: 1.586, 4.773]; P < .001), but it disappeared in stage IV disease. An indirect mechanism representing mediastinal lymphadenopathy was responsible for the accumulation in all but one patient with minimal pleural effusion.
  
  
  CONCLUSIONS
  Minimal pleural effusion is a common clinical finding in staging SCLC. Its presence is associated with worse survival in patients and should be considered when CT scans are interpreted.
authors: From the Center for Lung Cancer, Inha University Hospital, Incheon, South Korea (J.S.R., J.H.L., J.M.L., A.M., S.K.L., B.R.Y., H.J.K.); and Departments of Internal Medicine (J.S.R., J.H.L., J.M.L.), Diagnostic Radiology (W.C.K., K.H.L.), and Social and Preventive Medicine (S.S.H.), Inha University College of Medicine, 27 Inhang-Ro, Jung Gu, Incheon 400-103, South Korea.
authors: Jeong-Seon
authors: JS
authors: Ryu
authors: From the Center for Lung Cancer, Inha University Hospital, Incheon, South Korea (J.S.R., J.H.L., J.M.L., A.M., S.K.L., B.R.Y., H.J.K.); and Departments of Internal Medicine (J.S.R., J.H.L., J.M.L.), Diagnostic Radiology (W.C.K., K.H.L.), and Social and Preventive Medicine (S.S.H.), Inha University College of Medicine, 27 Inhang-Ro, Jung Gu, Incheon 400-103, South Korea.
authors: Jun Hyeok
authors: JH
authors: Lim
authors: From the Center for Lung Cancer, Inha University Hospital, Incheon, South Korea (J.S.R., J.H.L., J.M.L., A.M., S.K.L., B.R.Y., H.J.K.); and Departments of Internal Medicine (J.S.R., J.H.L., J.M.L.), Diagnostic Radiology (W.C.K., K.H.L.), and Social and Preventive Medicine (S.S.H.), Inha University College of Medicine, 27 Inhang-Ro, Jung Gu, Incheon 400-103, South Korea.
authors: Jeong Min
authors: JM
authors: Lee
authors: From the Center for Lung Cancer, Inha University Hospital, Incheon, South Korea (J.S.R., J.H.L., J.M.L., A.M., S.K.L., B.R.Y., H.J.K.); and Departments of Internal Medicine (J.S.R., J.H.L., J.M.L.), Diagnostic Radiology (W.C.K., K.H.L.), and Social and Preventive Medicine (S.S.H.), Inha University College of Medicine, 27 Inhang-Ro, Jung Gu, Incheon 400-103, South Korea.
authors: Woo Chul
authors: WC
authors: Kim
authors: From the Center for Lung Cancer, Inha University Hospital, Incheon, South Korea (J.S.R., J.H.L., J.M.L., A.M., S.K.L., B.R.Y., H.J.K.); and Departments of Internal Medicine (J.S.R., J.H.L., J.M.L.), Diagnostic Radiology (W.C.K., K.H.L.), and Social and Preventive Medicine (S.S.H.), Inha University College of Medicine, 27 Inhang-Ro, Jung Gu, Incheon 400-103, South Korea.
authors: Kyung-Hee
authors: KH
authors: Lee
authors: From the Center for Lung Cancer, Inha University Hospital, Incheon, South Korea (J.S.R., J.H.L., J.M.L., A.M., S.K.L., B.R.Y., H.J.K.); and Departments of Internal Medicine (J.S.R., J.H.L., J.M.L.), Diagnostic Radiology (W.C.K., K.H.L.), and Social and Preventive Medicine (S.S.H.), Inha University College of Medicine, 27 Inhang-Ro, Jung Gu, Incheon 400-103, South Korea.
authors: Azra
authors: A
authors: Memon
authors: From the Center for Lung Cancer, Inha University Hospital, Incheon, South Korea (J.S.R., J.H.L., J.M.L., A.M., S.K.L., B.R.Y., H.J.K.); and Departments of Internal Medicine (J.S.R., J.H.L., J.M.L.), Diagnostic Radiology (W.C.K., K.H.L.), and Social and Preventive Medicine (S.S.H.), Inha University College of Medicine, 27 Inhang-Ro, Jung Gu, Incheon 400-103, South Korea.
authors: Seul-Ki
authors: SK
authors: Lee
authors: From the Center for Lung Cancer, Inha University Hospital, Incheon, South Korea (J.S.R., J.H.L., J.M.L., A.M., S.K.L., B.R.Y., H.J.K.); and Departments of Internal Medicine (J.S.R., J.H.L., J.M.L.), Diagnostic Radiology (W.C.K., K.H.L.), and Social and Preventive Medicine (S.S.H.), Inha University College of Medicine, 27 Inhang-Ro, Jung Gu, Incheon 400-103, South Korea.
authors: Bo-Rim
authors: BR
authors: Yi
authors: From the Center for Lung Cancer, Inha University Hospital, Incheon, South Korea (J.S.R., J.H.L., J.M.L., A.M., S.K.L., B.R.Y., H.J.K.); and Departments of Internal Medicine (J.S.R., J.H.L., J.M.L.), Diagnostic Radiology (W.C.K., K.H.L.), and Social and Preventive Medicine (S.S.H.), Inha University College of Medicine, 27 Inhang-Ro, Jung Gu, Incheon 400-103, South Korea.
authors: Hyun-Jung
authors: HJ
authors: Kim
authors: From the Center for Lung Cancer, Inha University Hospital, Incheon, South Korea (J.S.R., J.H.L., J.M.L., A.M., S.K.L., B.R.Y., H.J.K.); and Departments of Internal Medicine (J.S.R., J.H.L., J.M.L.), Diagnostic Radiology (W.C.K., K.H.L.), and Social and Preventive Medicine (S.S.H.), Inha University College of Medicine, 27 Inhang-Ro, Jung Gu, Incheon 400-103, South Korea.
authors: Seung-Sik
authors: SS
authors: Hwang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001999:Bronchoscopy; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D016066:Pleural Effusion, Malignant / Q000000981:diagnostic imaging* / Q000473:pathology; D011379:Prognosis; D012189:Retrospective Studies; D055752:Small Cell Lung Carcinoma / Q000000981:diagnostic imaging* / Q000473:pathology; D016019:Survival Analysis; D014057:Tomography, X-Ray Computed / Q000379:methods*