Mediastinal nodal staging of nonsmall cell lung cancer using integrated ¹⁸F‐FDG PET/CT in a tuberculosis‐endemic country

Abstract

BACKGROUNDIntegrated 18fluorine fluorodeoxyglucose (18F‐FDG) positron emission tomography/computed tomography (PET/CT) has shown somewhat variable sensitivity and specificity for mediastinal nodal staging in granulomatous disease endemic areas. The purpose of the study was to prospectively evaluate the efficacy of PET/CT for mediastinal nodal staging in nonsmall cell lung cancer (NSCLC) patients in a tuberculosis‐endemic country.METHODSProspective assessment of the diagnostic efficacy of integrated PET/CT for detecting mediastinal nodal metastasis was performed in 674 patients (M:F ratio = 502:172; mean age, 61 years) with NSCLC. Patients underwent an integrated PET/CT examination and subsequent surgical nodal staging (by mediastinoscopy only in 121 patients and by thoracotomy in 553). Nodes showing greater 18F‐FDG uptake than mediastinum at PET without benign calcification or high attenuation >70 household unit (HU) at unenhanced CT were regarded as being positive for malignancy. The histologic nodal assessment results were used as reference standards.RESULTSOf 2477 mediastinal nodal stations evaluated in 674 patients, 275 (11%) stations in 180 (27%) patients proved to be malignant. On a per‐person basis, the overall sensitivity, specificity, and accuracy of PET/CT for mediastinal nodal staging were 61% (110 of 180), 96% (473 of 494), and 86% (583 of 674), respectively. On a per‐nodal station basis, they were 46% (126 of 275), 98% (2154 of 2202), and 92% (2280 of 2477).CONCLUSIONSIntegrated PET/CT provides high specificity and reasonably high accuracy, but somewhat low sensitivity for mediastinal nodal staging of NSCLCs. The high specificity is achieved at the expense of sensitivity by interpreting calcified nodes or nodes with high attenuation at CT, even with high FDG uptake at PET, as benign in a tuberculosis‐endemic region. Cancer 2007. © 2007 American Cancer Society.

Diagnostic Performance of 18F-FDG PET/CT for Lymph Node Staging in Patients with Operable Non-small-cell Lung Cancer and Inflammatory Lung Disease

“…Inflammatory lung disease is a well-known cause of false-positive FDG accumulation in both lung parenchyme and lymph nodes, which could overstage patients with lung cancer [15,16]. Since Korea is an endemic area of tuberculosis, diagnostic accuracy of 18 F-FDG PET/CT in lung cancer staging would be lower than expected. In a recent study it has been suggested that the diagnostic accuracy of 18 F-FDG PET for mediastinal lymph node staging is not enough to replace mediastinoscopy in regions with high prevalence of inflammatory lung disease [17].…”

“…The usefulness of 18 F-fluorodeoxyglucose positron emission tomography (FDG PET) in non-small-cell lung cancer has been proven in various clinical situations, including differential diagnosis of solitary pulmonary nodules, staging, detection of recurrence, therapeutic monitoring, planning of radiotherapy, and prognosis [1][2][3][4]. 18 F-FDG PET is known to have improved the accuracy of staging for non-small-cell lung cancer compared with the conventional imaging modality [5].…”

“…18 F-FDG PET is known to have improved the accuracy of staging for non-small-cell lung cancer compared with the conventional imaging modality [5]. Moreover, the introduction of integrated positron emission tomography/computed tomography (PET/ CT), which provides both metabolic and morphologic information of lesions within a single study, enhanced the diagnostic accuracy compared with conventional PET or CT alone [6][7][8].…”

“…Both PET and integrated PET/CT have shown higher accuracy in lymph node staging of lung cancer than conventional CT [5,[9][10][11][12][13]. However, 18 F-FDG is not tumor-specific, therefore, it can be taken up by various physiologic changes or benign pathologic lesions [14]. The misinterpretation of such findings as malignancy may lead to unnecessary diagnostic tests or surgical procedures.…”

“…In a recent study it has been suggested that the diagnostic accuracy of 18 F-FDG PET for mediastinal lymph node staging is not enough to replace mediastinoscopy in regions with high prevalence of inflammatory lung disease [17]. Moreover, a clinical study showed somewhat low sensitivity (61%) of 18 F-FDG PET/CT for mediastinal lymph node staging in a tuberculosis-endemic country [18].…”