title: FDG PET/CT for assessing the resectability of NSCLC patients with N2 disease after neoadjuvant therapy.
abstract: OBJECTIVE
  Neoadjuvant chemoradiotherapy (CMRT) is the most effective treatment of stage III non-small-cell lung cancer (NSCLC). The present study aimed at assessing FDG PET/CT for defining the response of N2 disease to neoadjuvant CMRT, as surgical resection after such therapy significantly improves 5-year survival in responding N2 disease.
  
  
  METHODS
  Forty-five patients with locally advanced NSCLC underwent both pre-neoadjuvant therapy FDG PET/CT and post-neoadjuvant therapy FDG PET/CT followed by anatomical resection of lung and ipsilateral mediastinal lymph nodes (LN). Seventeen of these patients who had PET/CT studies in our institution and were operated after CMRT were retrospectively included in the study group (12 males, ages 43-78 years; stage IIIA: 14 patients, stage IIIB: 3 patients). PET/CT response in N2 was visually scored per-lymph node station and per patient. Quantitative N2 response was evaluated by SUVmax and total lesion glycolysis (TLG) measurements after therapy alone and in comparison with pre-therapy values. PET/CT N2 response was confirmed at surgery.
  
  
  RESULTS
  Seventeen NSCLC patients with 29 metastatic N2 lymph nodes (LN) were assessed. Histopathology confirmed 14 responders and 3 non-responders, and was available in 20/29 metastatic LN, showing complete response in 17 and residual disease in 3 LN. LN-based visual analysis of N2 response on PET/CT defined 3 TP, 16 TN and 1 FP, for sensitivity, specificity, accuracy, negative and positive predictive values (NPV and PPV) of 100, 94, 95, 100 and 75%, respectively. Patient-based visual analysis defined 3 TP, 13 TN and 1 FP study, for sensitivity, specificity, accuracy, NPV and PPV of 100, 93, 94, 100 and 75%, respectively. Nodal-based quantitative analysis of FDG uptake in N2 nodes revealed a significant difference between responding and non-responding LN only of SUVmax post-therapy (2.5 ± 1.21 vs. 3.5 ± 2.36, P = 0.04).
  
  
  CONCLUSIONS
  FDG PET/CT after neoadjuvant therapy accurately defined response in metastatic N2 nodes of NSCLC patients, presenting very high sensitivity and NPV for detecting responding nodes. PET/CT may enable selection of candidates for curative resection of stage III NSCLC. Mediastinoscopy may not be mandatory in patients with a negative PET/CT after neoadjuvant therapy.
authors.affiliation: Department of General Thoracic Surgery, Rambam Health Care Campus, P.O.B. 9602, 31096, Haifa, Israel. r_kremer@rambam.health.gov.il.
authors.forename: Ran
authors.initials: R
authors.lastname: Kremer
authors.affiliation: Department of General Thoracic Surgery, Rambam Health Care Campus, P.O.B. 9602, 31096, Haifa, Israel.
authors.forename: Yury
authors.initials: Y
authors.lastname: Peysakhovich
authors.affiliation: Department of General Thoracic Surgery, Rambam Health Care Campus, P.O.B. 9602, 31096, Haifa, Israel.
authors.forename: Levy-Faber
authors.initials: LF
authors.lastname: Dan
authors.affiliation: Department of Diagnostic Radiology, Rambam Health Care Campus, Haifa, Israel.
authors.forename: Ludmila
authors.initials: L
authors.lastname: Guralnik
authors.affiliation: Department of Nuclear Medicine, Rambam Health Care Campus, Haifa, Israel.
authors.forename: Olga
authors.initials: O
authors.lastname: Kagna
authors.affiliation: Department of General Thoracic Surgery, Rambam Health Care Campus, P.O.B. 9602, 31096, Haifa, Israel. rony.nir@gmail.com.
authors.forename: Rony-Reuven
authors.initials: RR
authors.lastname: Nir
authors.affiliation: Department of Nuclear Medicine, Rambam Health Care Campus, Haifa, Israel.|Department of Nuclear Medicine, Shaare Zedek Medical Center, Jerusalem, Israel.
authors.forename: Rachel
authors.initials: R
authors.lastname: Bar-Shalom
mesh_terms: D000328:Adult; D000368:Aged; D002289:Carcinoma, Non-Small-Cell Lung / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery* / Q000628:therapy; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery* / Q000628:therapy; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D016896:Treatment Outcome
chemical_list: D019788:Fluorodeoxyglucose F18
keywords: FDG PET/CT; N2 disease; NSCLC; Neoadjuvant therapy; Resectability