title: False-positivity of mediastinal lymph nodes has negative effect on survival in potentially resectable non-small cell lung cancer.
abstract: OBJECTIVE
  It has been shown that increased metabolic activity of primary tumour has a negative effect on survival in non-small cell lung cancer (NSCLC) staged with positron emission tomography integrated computed tomography (PET/CT). We hypothesized that an increased metabolic activity of mediastinal lymph nodes would have worse survival even if it is false.
  
  
  METHODS
  Three hundred and twenty-eight consecutive patients with NSCLC histology were imaged with PET/CT within 90 days of surgery between September 2005 and March 2009. Patients who had neoadjuvant chemotherapy (n = 22), patients with prior history of NSCLC (n = 9) or other malignancies within 5 years (n = 11) were excluded from the study. Patients with negative mediastinoscopy underwent resection. Pathological results were revised according to the seventh tumor-node-metastasis staging system. Kaplan-Meier test was used for survival. Log-rank and Cox analyses were used for comparisons.
  
  
  RESULTS
  A total of 286 patients (262 male; mean age: 58.5 years) were evaluated. There were 22 (6.7%) operative deaths and none of the patients were lost to follow-up. The median follow-up in the remaining 264 patients was 26 months (range, 2-61 months). Tumour size, nodal spread and stage were all strongly associated with survival from NSCLC (P < 0.001). There were 63 true-positive, 65 false-positive (FP), 152 true-negative (TN) and six false-negative findings on mediastinal staging after PET/CT. The maximum standardized uptake value of primary tumour was significantly higher in FP patients than in TN patients (P = 0.012). After excluding pN2-positive patients, TN patients had better survival than FP patients (P = 0.006). Multivariate analysis showed that false-positivity of mediastinal lymph nodes was independently associated with worse survival (hazard ratio = 0.63; P = 0.02). There were 146 patients with pT1-4, pN0 treated with R0 surgical resection. Disease-free survival and overall survival were also significantly better for TN patients in completely resected group (P = 0.009 versus 0.016).
  
  
  CONCLUSIONS
  We have shown that false-positivity of mediastinal lymph nodes had yielded worse survival in surgically staged or resected NSCLC patients staged with PET/CT. This result may help to allocate patients with potentially poor prognosis for considered additional therapy.
authors.affiliation: Department of Thoracic Surgery, Dr Selahattin Cizrelioglu State Hospital, Cizre, Sirnak, Turkey. ilker.iskender@yahoo.ca
authors.forename: Ilker
authors.initials: I
authors.lastname: Iskender
authors.forename: Salih Zeki
authors.initials: SZ
authors.lastname: Kadioglu
authors.forename: Tugba
authors.initials: T
authors.lastname: Cosgun
authors.forename: Hasan Oguz
authors.initials: HO
authors.lastname: Kapicibasi
authors.forename: Gonul
authors.initials: G
authors.lastname: Sagiroglu
authors.forename: Altug
authors.initials: A
authors.lastname: Kosar
authors.forename: Altan
authors.initials: A
authors.lastname: Kir
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging / Q000473:pathology / Q000556:secondary* / Q000601:surgery*; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D008207:Lymphatic Metastasis; D008297:Male; D008482:Mediastinum; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods; D009367:Neoplasm Staging; D011013:Pneumonectomy / Q000379:methods; D049268:Positron-Emission Tomography; D011379:Prognosis; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome