Application of 18F-deoxyglucose PET-CT in diagnosing positive sentinel lymph nodes of peripheral non-small cell lung cancer

Abstract

Objective To analyze the sensitivity, specificity and accuracy as well as correlation of positive lymph nodes diagnosed by 18F-deoxyglucose positron emission computed tomography(PET-CT) and sentinel lymph nodes (SLN) detected using blue dyes in lymph node metastasis of peripheral non-small cell cancer (NSCLC), and investigate the value of PET-CT in SLN of lung cancer and its significance with mediastinal lymph nodes dissection. Methods Sixty patients with resectable peripheral NSCLC were randomly selected from Shandong Province Cancer Hospital between July 2012 and June 2014 in this study. All patients underwent integrated PET-CT before operation for lymph node staging. The first lymph nodes to stain blue with oleophilic isosulfan blue dye defined as SLN were sent separately for fast pathological examination at thoracotomy, then all the non-SLN detected intraoperatively were also sent for hematoxylin-eosin(H-E) staining and immunohistochemical examination after pneumectomy. Pathological diagnosis was served as golden standard for comparing PET-CT with SLN. Results At thoracotomy, SLNs were successful identified in 37 of 60 peripheral NSCLC patients injected with isosulfan blue dye, and the rate of SLN detection was 61.7%. Eighty-five blue-stained SLNs were resected. Of them, 52 SLNs in 18 patients were proved negative, while 15 of these 18 patients were diagnosed N0 by PET-CT before operation, and 4 patients(22.2%) had only non-SLN metastasis. Thirty-three SLNs in 19 patients were proved positive, while 15 patients including 25 SLNs were diagnosed positive by PET-CT before operation, with the sensitivity, specificity, positive predictive value, negative predictive value and coincidence rate of PET-CT for SLN diagnosis of 78.9%(15/19), 83.3% (15/18) , 83.3% (15/18), 78.9% (15/19) and 81.1%(30/37), respectively. Conclusions Integrated PET-CT diagnoses SLN quite precisely. PET-CT shows high coincidence rate for clinical staging and postoperative pathological staging in NSCLC. Combined PET-CT and SLN procedure facilitates the precise estimation of localized lymph node involved as well as the determination of relevant pattern of lymphadenectomy, which may accordingly have important impact on the prognosis and postoperative treament in NSCLC patients. Key words: Carcinoma, non-small cell lung; Tomography, emission-computed; Lymph node; Diagnosis