title: SUVmax/THKmax as a biomarker for distinguishing advanced gastric carcinoma from primary gastric lymphoma.
abstract: BACKGROUND
  Gastric carcinoma and primary gastric lymphoma (PGL) are the two most common malignancies in stomach. The purpose of this study was to screen and validate a biomarker of (18)F-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) for distinguishing advanced gastric carcinoma (AGC) from PGL for clinical applications.
  
  
  RESULTS
  We reviewed PET/CT scans collected from January 2008 to April 2012 of 69 AGC and 38 PGL (14 low-grade mucosa-associated lymphoid tissue [MALT], 24 non-MALT aggressive non-Hodgkin lymphoma [ANHL]) with a focus on FDG intensity (maximum standardized uptake value [SUVmax]) of primary lesions and its CT-detected abnormalities, including maximal gastrointestinal wall thickness (THKmax) and mucosal ulcerations. Gastric FDG uptake was found in 69 (100%) patients with AGC and 36 (95%, 12 MALT vs. 24 ANHL)with PGL. The presence of CT-detected abnormalities of AGC and PGL were 97% (67/69) and 89% (12 MALT vs. 22 ANHL), respectively. After controlling for THKmax, SUVmax was higher with ANHL than AGC (17.10 ± 8.08 vs. 9.65 ± 5.24, p<0.05) and MALT (6.20 ± 3.60, p<0.05). THKmax did not differ among MALT, ANHL and AGC. Mucosal ulceration was more common with AGC (n = 9) than PGL (n = 2),but the difference was not statistically significant (p>0.05). Cross-validation analysis showed that for distinguishing ANHL from AGC, the classifier with SUVmax as a feature achieved a correct classification rate of 81% with thresholds 13.40 ± 1.12 and the classifier with SUVmax/THKmax as a feature achieved a correct classification rate of 83% with thresholds 7.51 ± 0.63.
  
  
  CONCLUSIONS
  SUVmax/THKmax may be as a promising biomarker of FDG-PET/CT for distinguishing ANHL from AGC. Structural CT abnormalities alone may not be reliable but can help with PET assessment of gastric malignancies. (18)F-FDG PET/CT have potential for distinguishing AGC from PGL at the individual level.
authors.affiliation: Department of Nuclear Medicine, General Hospital of the Chinese People's Liberation Army and Military Medical Postgraduate College, Beijing, China.
authors.forename: Liping
authors.initials: L
authors.lastname: Fu
authors.forename: Hongming
authors.initials: H
authors.lastname: Li
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.forename: Baixuan
authors.initials: B
authors.lastname: Xu
authors.forename: Yong
authors.initials: Y
authors.lastname: Fan
authors.forename: Jiahe
authors.initials: J
authors.lastname: Tian
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism*; D003937:Diagnosis, Differential; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D005753:Gastric Mucosa / Q000000981:diagnostic imaging / Q000473:pathology*; D006801:Humans; D008228:Lymphoma, Non-Hodgkin / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D013274:Stomach Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D014057:Tomography, X-Ray Computed; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; D019788:Fluorodeoxyglucose F18