title: Predictive value of pretreatment metabolic activity measured by fluorodeoxyglucose positron emission tomography in patients with metastatic advanced gastric cancer: the maximal SUV of the stomach is a prognostic factor.
abstract: OBJECTIVE
  Few studies have evaluated metabolic activity by (18)F-FDG PET as a prognostic factor in advanced gastric cancer (AGC). We investigated its prognostic role in metastatic AGC.
  
  
  METHODS
  We enrolled 82 patients with metastatic AGC, who were treatment-naive and underwent pretreatment (18)F-FDG PET/CT scanning. In each patient, the maximal standardized uptake value (SUVmax) was measured in each target lesion. Stomach(SUVmax) was defined as SUVmax in the stomach, while Total(SUVmax) was defined as the highest SUVmax among all the target lesions.
  
  
  RESULTS
  The stomach was the organ most frequently displaying the highest SUVmax among all the target lesions (in 67.1% of patients). A Total(SUVmax) value of 11.5 was the value with the maximum sum of sensitivity and specificity from receiver-operating characteristic curves for progression-free survival (PFS). PFS was significantly longer in patients with a Total(SUVmax) value <11.5 than in those with a Total(SUVmax) value ≥11.5 (P = 0.023); however, overall survival (OS) was not (P = 0.055). A Stomach(SUVmax) value of 6.0 was derived by similar methods. PFS and OS were significantly longer in those with a Stomach(SUVmax) value <6.0 than in those with a Stomach(SUVmax) value ≥6.0 (P = 0.001 and P = 0.006, respectively). Furthermore, those with a low Total(SUVmax) and those with a low Stomach(SUVmax) showed better chemotherapeutic responses (P = 0.016 and P = 0.034, respectively). Among patients with histologically undifferentiated carcinomas, those with lower Total(SUVmax) and those with lower Stomach(SUVmax) showed longer median PFS (P = 0.027 and P = 0.005, respectively) and OS (P = 0.009 and P <0.001, respectively). Multivariate analysis demonstrated Stomach(SUVmax) as an independent predictor of PFS (P = 0.002) and OS (P = 0.038).
  
  
  CONCLUSIONS
  Pretreatment metabolic activity may be a useful prognostic marker in patients with metastatic AGC undergoing palliative chemotherapy. Notably, Stomach(SUVmax) was the single, most robust factor predicting prognosis.
authors.affiliation: Department of Internal Medicine and Institute of Gastroenterology, Yonsei University College of Medicine, Seoul 120-752, Korea.
authors.forename: Jun Chul
authors.initials: JC
authors.lastname: Park
authors.forename: Jae-Hoon
authors.initials: JH
authors.lastname: Lee
authors.forename: Kungseok
authors.initials: K
authors.lastname: Cheoi
authors.forename: Hyunsoo
authors.initials: H
authors.lastname: Chung
authors.forename: Mi Jin
authors.initials: MJ
authors.lastname: Yun
authors.forename: Hyuk
authors.initials: H
authors.lastname: Lee
authors.forename: Sung Kwan
authors.initials: SK
authors.lastname: Shin
authors.forename: Sang Kil
authors.initials: SK
authors.lastname: Lee
authors.forename: Yong Chan
authors.initials: YC
authors.lastname: Lee
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging* / Q000378:metabolism* / Q000473:pathology / Q000556:secondary; D000328:Adult; D000368:Aged; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D009362:Neoplasm Metastasis; D049268:Positron-Emission Tomography / Q000379:methods*; D011237:Predictive Value of Tests; D011379:Prognosis; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D013274:Stomach Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism* / Q000473:pathology; D014057:Tomography, X-Ray Computed; D055815:Young Adult
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18