title: Postoperative change of the psoas muscle area as a predictor of survival in surgically treated esophageal cancer patients.
abstract: BACKGROUND
  Although a decrease in the psoas muscle area (PMA) has been reported as a risk factor for survival after esophagectomy in esophageal cancer, no previous studies have focused on the change in the PMA after surgery. We investigated the prognostic role of PMA changes in patients with surgically treated esophageal cancer.
  
  
  METHODS
  Fifty-eight patients with esophageal cancer who underwent surgical resection and complete lymph node dissection were reviewed retrospectively. The PMA was measured at the level of the L3 vertebrae on preoperative and one-year postoperative follow-up computed tomography images. The percentage change of the PMA was calculated as follows: delta (%) = (postoperative PMA - preoperative PMA) / (preoperative PMA × 100).
  
  
  RESULTS
  The study patients included 54 (93.1%) males and 4 females (mean age, 60.59±9.16 years), of whom 17 (29.3%) were pathological Stage I, 18 (31.0%) were Stage II, and 23 (39.7%) were Stage III. The mean change of the PMA was -10.17% and the postoperative PMA was decreased significantly compared with the preoperative PMA (P<0.001). The PMA was increased in 13 (22.4%) patients, whereas it was decreased in 45 (77.6%). Multivariate analysis revealed that the change of the PMA (hazard ratio, HR =0.688; P=0.001) and the pathologic stage (Stage IIIvs. Stage I, HR =3.388; P=0.016) were risk factors for overall survival (OS). The 3-year OS in patients with a PMA decrease of more than 10%, and those with a PMA decrease of less than 10% or an increase, were 18.9% and 59.5%, respectively (P=0.049).
  
  
  CONCLUSIONS
  The decrease in the PMA had a negative prognostic effect on OS in patients with surgically treated esophageal cancer.
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, Ajou University School of Medicine, Suwon, Republic of Korea.
authors.forename: Seong Yong
authors.initials: SY
authors.lastname: Park
authors.affiliation: Department of Nuclear Medicine & Molecular Imaging, Ajou University School of Medicine, Suwon, Republic of Korea.
authors.forename: Joon-Kee
authors.initials: JK
authors.lastname: Yoon
authors.affiliation: Department of Nuclear Medicine & Molecular Imaging, Ajou University School of Medicine, Suwon, Republic of Korea.
authors.forename: Su Jin
authors.initials: SJ
authors.lastname: Lee
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, Ajou University School of Medicine, Suwon, Republic of Korea.
authors.forename: Seokjin
authors.initials: S
authors.lastname: Haam
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, Ajou University School of Medicine, Suwon, Republic of Korea.
authors.forename: Joonho
authors.initials: J
authors.lastname: Jung
keywords: Esophageal cancer; psoas muscle area (PMA); statistics; survival analysis