title: Evaluation of the factors affecting the maximum standardized uptake value of metastatic lymph nodes in different histological types of non-small cell lung cancer on PET-CT.
abstract: BACKGROUND
  To evaluate the factors affecting the maximum standardized uptake value (SUVmax) of metastatic lymph nodes in different histological types of non-small cell lung cancer (NSCLC) on integrated positron emission tomography and computed tomography (PET-CT).
  
  
  METHODS
  This was a retrospective, single-institution review of 122 patients with pathologically proven NSCLC who had PET-CT scanning at the same center. Lymph node metastases were pathologically confirmed in tissue specimens from surgical patients. Statistical evaluation of PET-CT results was performed on a per-nodal-station basis.
  
  
  RESULTS
  The tumor SUVmax of squamous cell carcinoma (SCC) (11.0 ± 4.1) was higher than that of adenocarcinoma (AC) (7.4 ± 4.4) (P < 0.01), however, the SUVmax of the metastatic lymph nodes did not differ between the SCC (4.6 ± 3.1) and AC groups(3.6 ± 2.5) (P = 0.221). The SUVmax of metastatic lymph nodes was positively correlated with lymph node size but not with the primary tumor SUVmax, primary tumor size, tumor location and tumor differentiation. The frequency of a SUVmax of lymph nodes ≥2.5 was 44%, 80%,100% in SCC group and 39%, 59%, 90% in AC group when the short-axis diameter of metastatic lymph node was <10 mm, 10-15 mm, and > 15 mm, respectively. The low sensitivity for metastatic lymph nodes on PET-CT was increased when the SUVmax cut-off for malignancy was considered to be above the normal background compared with that when the SUVmax cut-off was above 2.5.
  
  
  CONCLUSIONS
  There was no difference in the SUVmax of metastatic lymph nodes in the SCC and AC groups. The SUVmax of metastatic lymph nodes was positively correlated with metastatic lymph node size. There was a high false negative rate if lymph nodes with a short-axis diameter less than 10 mm and a extremely low false negative rate if lymph nodes with a short-axis diameter higher than 15 mm. Although an increased sensitivity may be achieved by decreasing the SUVmax cut-off, invasive staging may still be required for negative lymph nodes due to the lower sensitivity of PET-CT in both SCC and AC.
authors.affiliation: Department of Respiratory Medicine, the First Affiliated Hospital, College of Medicine, Zhejiang University, 79 Qingchun Road, Hangzhou, China. yuehongw@hotmail.com.
authors.forename: Yuehong
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Respiratory Medicine, the First Affiliated Hospital, College of Medicine, Zhejiang University, 79 Qingchun Road, Hangzhou, China. mashanni1208@163.com.
authors.forename: Shanni
authors.initials: S
authors.lastname: Ma
authors.affiliation: Department of Nuclear Medicine, the First Affiliated Hospital, College of Medicine, Zhejiang University, 79 Qingchun Road, Hangzhou, China. dongmenjie@126.com.
authors.forename: Mengjie
authors.initials: M
authors.lastname: Dong
authors.affiliation: Department of Respiratory Medicine, the First Affiliated Hospital, College of Medicine, Zhejiang University, 79 Qingchun Road, Hangzhou, China. yakeyao0930@126.com.
authors.forename: Yake
authors.initials: Y
authors.lastname: Yao
authors.affiliation: Department of Nuclear Medicine, the First Affiliated Hospital, College of Medicine, Zhejiang University, 79 Qingchun Road, Hangzhou, China. 475877882@qq.com.
authors.forename: Kanfeng
authors.initials: K
authors.lastname: Liu
authors.affiliation: Department of Respiratory Medicine, the First Affiliated Hospital, College of Medicine, Zhejiang University, 79 Qingchun Road, Hangzhou, China. zjyhz@zju.edu.cn.
authors.forename: Jianying
authors.initials: J
authors.lastname: Zhou
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis* / Q000601:surgery; D000368:Aged; D002289:Carcinoma, Non-Small-Cell Lung / Q000175:diagnosis* / Q000601:surgery; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis* / Q000601:surgery; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000601:surgery; D008198:Lymph Nodes / Q000000981:diagnostic imaging*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D011013:Pneumonectomy; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D047368:Tumor Burden
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18