title: Prospective study of transsphenoidal pituitary surgery: is tumor volume a predictor for the residual tumor?
abstract: BACKGROUND
  The presence of residual tumor after surgery for pituitary adenoma may necessitate further treatment. The suprasellar and parasellar extension of the tumor have been widely considered as the predictors for residual tumor. However there is scarcity of studies regarding the preoperative tumor volume and residual tumor. This study was conducted to evaluate if tumor volume could predict the outcome of transsphenoidal pituitary surgery.
  
  
  METHODS
  A prospective study was designed and 48 patients who underwent transsphenoidal pituitary surgery within 1 year in the First Affiliated Hospital of Xi'an Jiaotong University were included in this study. The preoperative tumor volume and immediate postoperative tumor volume (within 4 - 7 days) were calculated in the contrast magnetic resonance imaging by using the formula of ellipsoid. All these volumes were divided into three subgroups, i.e. group 1, group 2 and group 3 with preoperative volume of less than 4 cm(3), 4 - 8 cm(3), and more than 8 cm(3) respectively. The parasellar and suprasellar extension of the tumor were also classified by Knosp and modified Hardy's classifications.
  
  
  RESULTS
  Baseline characteristics were comparable. The preoperative tumor volume of more than 8 cm(3) (group 3, (12.1 ± 1.1) cm(3)) had increased risk on postoperative tumor residue (P < 0.01) than the other two groups ((2.1 ± 0.3) cm(3) and (6.1 ± 0.3) cm(3) in groups 1 and 2). The mean postoperative volume in group 3 patients ((2.2 ± 0.1) cm(3)) was significantly higher than the other two groups (P < 0.01).
  
  
  CONCLUSIONS
  Preoperative volume of more than 8 cm(3) can be considered as a predictor for postoperative residual volume.
authors.affiliation: Department of Neurosurgery, First Affiliated Hospital of Medical School, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, China.
authors.forename: Resha
authors.initials: R
authors.lastname: Shrestha
authors.forename: Lei
authors.initials: L
authors.lastname: Qi
authors.forename: Gang
authors.initials: G
authors.lastname: Bao
authors.forename: Mao-de
authors.initials: MD
authors.lastname: Wang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010902:Pituitary Gland / Q000473:pathology* / Q000601:surgery*; D010911:Pituitary Neoplasms / Q000473:pathology / Q000601:surgery; D011446:Prospective Studies; D016896:Treatment Outcome; D047368:Tumor Burden / Q000502:physiology; D055815:Young Adult