title: Assessment of metastatic risk of gastric GIST based on treatment-naïve CT features.
abstract: OBJECTIVE
  To study whether the CT features of treatment-naïve gastric GIST may be used to assess metastatic risk.
  
  
  METHODS
  In this IRB approved retrospective study, with informed consent waived, contrast enhanced CT images of 143 patients with pathologically confirmed treatment-naïve gastric GIST (74 men, 69 women; mean age 61 years, SD ± 14) were reviewed in consensus by two oncoradiologists blinded to clinicopathologic features and clinical outcome and morphologic features were recorded. The metastatic spread was recorded using available imaging studies and electronic medical records (median follow up 40 months, interquartile range, IQR, 21-61). The association of maximum size in any plane (≤10 cm or >10 cm), outline (smooth or irregular/lobulated), cystic areas (≤50% or >50%), exophytic component (≤50% or >50%), and enhancing solid component (present or absent) with metastatic disease were analyzed using univariate (Fisher's exact test) and multivariate (logistic regression) analysis.
  
  
  RESULTS
  Metastatic disease developed in 42 (29%) patients (28 at presentation, 14 during follow-up); 23 (16%) patients died. On multivariate analysis, tumor size >10 cm (p = 0.0001, OR 9.9), irregular/lobulated outline (p = 0.001, OR 5.6) and presence of a enhancing solid component (p < 0.0001, OR 9.1) were independent predictors of metastatic disease. On subgroup analysis, an irregular/lobulated outline and an enhancing solid component were more frequently associated with metastases in tumors ≤5 cm and >5-≤10 cm (p < 0.05).
  
  
  CONCLUSIONS
  CT morphologic features can be used to assess the metastatic risk of treatment-naïve gastric GIST. Risk assessment based on pretreatment CT is especially useful for patients receiving neoadjuvant tyrosine kinase inhibitors and those with tumors <5 cm in size.
authors.affiliation: Department of Imaging, Dana-Farber Cancer Institute, Boston, MA, USA.
authors.forename: A C
authors.initials: AC
authors.lastname: O'Neill
authors.affiliation: Department of Imaging, Dana-Farber Cancer Institute, Boston, MA, USA. Electronic address: ashinagare@partners.org.
authors.forename: A B
authors.initials: AB
authors.lastname: Shinagare
authors.affiliation: Department of Imaging, Dana-Farber Cancer Institute, Boston, MA, USA.
authors.forename: V
authors.initials: V
authors.lastname: Kurra
authors.affiliation: Department of Imaging, Dana-Farber Cancer Institute, Boston, MA, USA.
authors.forename: S H
authors.initials: SH
authors.lastname: Tirumani
authors.affiliation: Department of Imaging, Dana-Farber Cancer Institute, Boston, MA, USA.
authors.forename: J P
authors.initials: JP
authors.lastname: Jagannathan
authors.affiliation: Department of Imaging, Dana-Farber Cancer Institute, Boston, MA, USA.
authors.forename: A D
authors.initials: AD
authors.lastname: Baheti
authors.affiliation: Department of Pathology, Brigham and Women's Hospital Boston, MA, USA.
authors.forename: J L
authors.initials: JL
authors.lastname: Hornick
authors.affiliation: Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA.
authors.forename: S
authors.initials: S
authors.lastname: George
authors.affiliation: Department of Imaging, Dana-Farber Cancer Institute, Boston, MA, USA.
authors.forename: N H
authors.initials: NH
authors.lastname: Ramaiya
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017024:Chemotherapy, Adjuvant; D065426:Cytoreduction Surgical Procedures; D005260:Female; D005743:Gastrectomy; D046152:Gastrointestinal Stromal Tumors / Q000000981:diagnostic imaging* / Q000473:pathology / Q000556:secondary / Q000628:therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D020360:Neoadjuvant Therapy; D009362:Neoplasm Metastasis; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use; D012189:Retrospective Studies; D018570:Risk Assessment; D013274:Stomach Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy; D014057:Tomography, X-Ray Computed; D047368:Tumor Burden; D055815:Young Adult
chemical_list: D047428:Protein Kinase Inhibitors
keywords: CT; Gastrointestinal stromal tumor; Metastasis; Risk stratification; Stomach