PET-CT has low specificity for mediastinal staging of non-small-cell lung cancer in an endemic area for tuberculosis: a diagnostic test study (LACOG 0114)

Abstract

BackgroundThe present study aims to assess the performance of 18F-FDG PET-CT on mediastinal staging of non-small cell lung cancer (NSCLC) in a location with endemic granulomatous infectious disease.MethodsDiagnostic test study including patients aged 18 years or older with operable stage I-III NSCLC and indication for a mediastinal lymph node biopsy. All patients underwent a 18F-FDG PET-scan before invasive mediastinal staging, either through mediastinoscopy or thoracotomy, which was considered the gold-standard. Surgeons and pathologists were blinded for scan results. Primary endpoint was to evaluate sensitivity, specificity and positive and negative predictive values of PET-CT with images acquired in the 1st hour of the exam protocol, using predefined cutoffs of maximal SUV, on per-patient basis.ResultsOverall, 85 patients with operable NSCLC underwent PET-CT scan followed by invasive mediastinal staging. Mean age was 65 years, 49 patients were male and 68 were white. One patient presented with active tuberculosis and none had HIV infection. Using any SUV_max > 0 as qualitative criteria for positivity, sensitivity and specificity were 0.87 and 0.45, respectively. Nevertheless, even when the highest SUV cut-off was used (SUV_max ≥5), specificity remained low (0.79), with an estimated positive predictive value of 54%.ConclusionsOur findings are in line with the most recent publications and guidelines, which recommend that PET-CT must not be solely used as a tool to mediastinal staging, even in a region with high burden of tuberculosis.Trial registrationThe LACOG 0114 study was registered at ClinicalTrials.gov, before study initiation, under identifier NCT02664792.

IASLC Multidisciplinary Recommendations for Pathologic Assessment of Lung Cancer Resection Specimens After Neoadjuvant Therapy

“…In countries where infections such as tuberculosis are endemic, the impact of these on specimen assessment, particularly possible tumor bed overestimation, should be considered. [66][67][68] Current treatments should reflect the type of neoadjuvant therapy (chemotherapy, immunotherapy, radiation therapy, targeted therapy, or combinations), date of previous treatment, and any pneumonitis associated with therapy. The site of the specimen, type of operation, adherent tissue included (in case of extended resection), and N1 and N2 lymph nodes (separately indicated by station) should be noted on the paperwork submitted to pathologic laboratory with the specimen.…”

Lung Cancer in Brazil

“…In an area endemic for tuberculosis in Brazil, the specificity and positive predictive value of PET-CT in the context of mediastinal staging in NSCLC were estimated at 52% and 38%, respectively, highlighting the recommendation of histologic confirmation of suspected N2 disease. 4 Mediastinoscopy is the most popular method of invasive mediastinal staging, and the use of endobronchial ultrasound techniques is increasing. Unfortunately, the percentage of patients who still undergo preoperative mediastinal lymph node sampling is unknown.…”

EUS‐FNA, ancillary studies and their clinical utility in patients with mediastinal, pancreatic, and other abdominal lesions

“…The evaluation of mediastinal masses is often difficult because of a variety of pathologic causes, close proximity to vital structures and difficulty in obtaining access for biopsy. CT and positron emission tomography‐CT (PET‐CT) both lack the sensitivity and specificity required to establish an accurate diagnosis of mediastinal lesions, having a false‐positive rate of 54.8% 22 . Mediastinoscopy is the gold standard for analysis of mediastinal lymph nodes, but is expensive, invasive, requires general anesthesia and has attendant surgical risks attached.…”