title: Clinical role of a new prognostic score using platelet-to-lymphocyte ratio in patients with malignant pleural mesothelioma undergoing extrapleural pneumonectomy.
abstract: BACKGROUND
  To investigate the prognostic value of platelet-to-lymphocyte ratio (PLR) and create a new prognostic score in patients with malignant pleural mesothelioma (MPM) undergoing extrapleural pneumonectomy (EPP).
  
  
  METHODS
  Of 85 patients who underwent EPP for MPM over 10 years at Toronto General Hospital, 65 patients whose blood test results before initial therapy were available were retrospectively analyzed as a training cohort to identify and develop a prognostic score. Receiver operating characteristic (ROC) analysis was performed to examine cutoff values of hematologic parameters for survival. The prognostic score was externally validated in a cohort of 32 patients who underwent EPP for MPM over 13 years at two institutes in Japan.
  
  
  RESULTS
  In the training cohort, multivariate analysis confirmed sex (P=0.0053) and PLR (P=0.049) as independent predictors of overall survival. The prognostic score was established using sex and PLR. The score was defined as follows: female:male =0:1 point; PLR <215:>215=0:1 point. The patients were classified into three risk groups according to the sum of the points: risk 0 (0 point), 1 (1 point), and 2 (2 points). Median survival time of the patients in the training cohort according to the risk groups were not reached, 32.0 and 19.4 months for risk 0 (n=6), 1 (n=36) and 2 (n=23), respectively (P=0.0006). In the validation cohort, median survival time was not reached, 45.9 and 14.5 months for risk 0 (n=4), 1 (n=18) and 2 (n=10), respectively (P=0.0002).
  
  
  CONCLUSIONS
  The new prognostic score using PLR is simple and useful for predicting the prognosis of patients with MPM undergoing EPP. Further study should be done to examine the role of this scoring system to optimize treatment strategy.
authors.affiliation: 1 Division of Thoracic Surgery, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Canada ; 2 Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan ; 3 Department of Thoracic Surgery, Graduate School of Medicine, University of Tokyo, Tokyo, Japan ; 4 Division of Thoracic Oncology, National Kyushu Cancer Center, Fukuoka, Japan ; 5 Department of Radiation Oncology, 6 Department of Medical Oncology, 7 Department of Pathology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Canada.
authors.forename: Tetsuzo
authors.initials: T
authors.lastname: Tagawa
authors.affiliation: 1 Division of Thoracic Surgery, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Canada ; 2 Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan ; 3 Department of Thoracic Surgery, Graduate School of Medicine, University of Tokyo, Tokyo, Japan ; 4 Division of Thoracic Oncology, National Kyushu Cancer Center, Fukuoka, Japan ; 5 Department of Radiation Oncology, 6 Department of Medical Oncology, 7 Department of Pathology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Canada.
authors.forename: Masaki
authors.initials: M
authors.lastname: Anraku
authors.affiliation: 1 Division of Thoracic Surgery, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Canada ; 2 Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan ; 3 Department of Thoracic Surgery, Graduate School of Medicine, University of Tokyo, Tokyo, Japan ; 4 Division of Thoracic Oncology, National Kyushu Cancer Center, Fukuoka, Japan ; 5 Department of Radiation Oncology, 6 Department of Medical Oncology, 7 Department of Pathology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Canada.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Morodomi
authors.affiliation: 1 Division of Thoracic Surgery, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Canada ; 2 Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan ; 3 Department of Thoracic Surgery, Graduate School of Medicine, University of Tokyo, Tokyo, Japan ; 4 Division of Thoracic Oncology, National Kyushu Cancer Center, Fukuoka, Japan ; 5 Department of Radiation Oncology, 6 Department of Medical Oncology, 7 Department of Pathology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Canada.
authors.forename: Tomoyoshi
authors.initials: T
authors.lastname: Takenaka
authors.affiliation: 1 Division of Thoracic Surgery, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Canada ; 2 Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan ; 3 Department of Thoracic Surgery, Graduate School of Medicine, University of Tokyo, Tokyo, Japan ; 4 Division of Thoracic Oncology, National Kyushu Cancer Center, Fukuoka, Japan ; 5 Department of Radiation Oncology, 6 Department of Medical Oncology, 7 Department of Pathology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Canada.
authors.forename: Tatsuro
authors.initials: T
authors.lastname: Okamoto
authors.affiliation: 1 Division of Thoracic Surgery, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Canada ; 2 Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan ; 3 Department of Thoracic Surgery, Graduate School of Medicine, University of Tokyo, Tokyo, Japan ; 4 Division of Thoracic Oncology, National Kyushu Cancer Center, Fukuoka, Japan ; 5 Department of Radiation Oncology, 6 Department of Medical Oncology, 7 Department of Pathology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Canada.
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Takenoyama
authors.affiliation: 1 Division of Thoracic Surgery, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Canada ; 2 Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan ; 3 Department of Thoracic Surgery, Graduate School of Medicine, University of Tokyo, Tokyo, Japan ; 4 Division of Thoracic Oncology, National Kyushu Cancer Center, Fukuoka, Japan ; 5 Department of Radiation Oncology, 6 Department of Medical Oncology, 7 Department of Pathology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Canada.
authors.forename: Yukito
authors.initials: Y
authors.lastname: Ichinose
authors.affiliation: 1 Division of Thoracic Surgery, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Canada ; 2 Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan ; 3 Department of Thoracic Surgery, Graduate School of Medicine, University of Tokyo, Tokyo, Japan ; 4 Division of Thoracic Oncology, National Kyushu Cancer Center, Fukuoka, Japan ; 5 Department of Radiation Oncology, 6 Department of Medical Oncology, 7 Department of Pathology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Canada.
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Maehara
authors.affiliation: 1 Division of Thoracic Surgery, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Canada ; 2 Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan ; 3 Department of Thoracic Surgery, Graduate School of Medicine, University of Tokyo, Tokyo, Japan ; 4 Division of Thoracic Oncology, National Kyushu Cancer Center, Fukuoka, Japan ; 5 Department of Radiation Oncology, 6 Department of Medical Oncology, 7 Department of Pathology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Canada.
authors.forename: B C John
authors.initials: BC
authors.lastname: Cho
authors.affiliation: 1 Division of Thoracic Surgery, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Canada ; 2 Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan ; 3 Department of Thoracic Surgery, Graduate School of Medicine, University of Tokyo, Tokyo, Japan ; 4 Division of Thoracic Oncology, National Kyushu Cancer Center, Fukuoka, Japan ; 5 Department of Radiation Oncology, 6 Department of Medical Oncology, 7 Department of Pathology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Canada.
authors.forename: Ronald
authors.initials: R
authors.lastname: Feld
authors.affiliation: 1 Division of Thoracic Surgery, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Canada ; 2 Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan ; 3 Department of Thoracic Surgery, Graduate School of Medicine, University of Tokyo, Tokyo, Japan ; 4 Division of Thoracic Oncology, National Kyushu Cancer Center, Fukuoka, Japan ; 5 Department of Radiation Oncology, 6 Department of Medical Oncology, 7 Department of Pathology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Canada.
authors.forename: Ming-Sound
authors.initials: MS
authors.lastname: Tsao
authors.affiliation: 1 Division of Thoracic Surgery, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Canada ; 2 Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan ; 3 Department of Thoracic Surgery, Graduate School of Medicine, University of Tokyo, Tokyo, Japan ; 4 Division of Thoracic Oncology, National Kyushu Cancer Center, Fukuoka, Japan ; 5 Department of Radiation Oncology, 6 Department of Medical Oncology, 7 Department of Pathology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Canada.
authors.forename: Natasha
authors.initials: N
authors.lastname: Leighl
authors.affiliation: 1 Division of Thoracic Surgery, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Canada ; 2 Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan ; 3 Department of Thoracic Surgery, Graduate School of Medicine, University of Tokyo, Tokyo, Japan ; 4 Division of Thoracic Oncology, National Kyushu Cancer Center, Fukuoka, Japan ; 5 Department of Radiation Oncology, 6 Department of Medical Oncology, 7 Department of Pathology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Canada.
authors.forename: Andrea
authors.initials: A
authors.lastname: Bezjak
authors.affiliation: 1 Division of Thoracic Surgery, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Canada ; 2 Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan ; 3 Department of Thoracic Surgery, Graduate School of Medicine, University of Tokyo, Tokyo, Japan ; 4 Division of Thoracic Oncology, National Kyushu Cancer Center, Fukuoka, Japan ; 5 Department of Radiation Oncology, 6 Department of Medical Oncology, 7 Department of Pathology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Canada.
authors.forename: Shaf
authors.initials: S
authors.lastname: Keshavjee
authors.affiliation: 1 Division of Thoracic Surgery, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Canada ; 2 Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan ; 3 Department of Thoracic Surgery, Graduate School of Medicine, University of Tokyo, Tokyo, Japan ; 4 Division of Thoracic Oncology, National Kyushu Cancer Center, Fukuoka, Japan ; 5 Department of Radiation Oncology, 6 Department of Medical Oncology, 7 Department of Pathology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Canada.
authors.forename: Marc
authors.initials: M
authors.lastname: de Perrot
keywords: Mesothelioma; platelet; surgery