45PD - Mediastinal nodal staging of non-small cell lung cancer using PET-CT in a tuberculosis-endemic country

Date 06 May 2017
Event ELCC 2017
Session Imaging and locally advanced NSCLC
Topics Non-Small-Cell Lung Cancer, Metastatic
Imaging, Diagnosis and Staging
Lung and other Thoracic Tumours
Presenter Bharat Khurse
Citation Annals of Oncology (2017) 28 (suppl_2): ii14-ii16. 10.1093/annonc/mdx086
Authors B.B. Khurse1, S. Kumar1, S. Deo1, P. Malik1, V. Kumar1, R. Kumar2, D. Jain2
  • 1Surgical Oncology, B.R. Ambedkar Institute Rotary Cancer Hospital (AIMS), 110029 - New Delhi/IN
  • 2All India Institute of Medical Sciences, New Delhi/IN

Abstract

Background

Integrated 18F-FDG, PET-CT has shown somewhat variable sensitivity and specificity for nodal staging in tuberculosis endemic areas. This variation is mainly because PET scans show falsely increased 18F-FDG uptake in inflammatory nodes, which may be observed in lymph nodes containing calcification or showing higher attenuations than those of surrounding vessels on unenhanced CT scans. The AIM of the study was to evaluate the efficacy of PET-CT for mediastinal nodal staging in non-small cell lung cancer (NSCLC) patients in a tuberculosis-endemic country.

Methods

From February 2012 to February 2016, a total of 160 patients underwent surgery for pathologically proven NSCLC. Patients who received neoadjuvant treatment were excluded from the study. Assessment of the diagnostic efficacy of integrated PET- CT for detecting nodal metastasis was performed in 46 patients (Male to Female ratio:4; mean age- 55 years). Patients underwent an integrated PET/CT examination and subsequent surgical nodal staging. Nodes showing greater 18F-FDG uptake at PET without benign calcification or high attenuation >70 household unit (HU) at unenhanced CT were regarded as being positive for malignancy. All patients underwent hilar and mediastinal lymph node dissection according to the AJCC lymph node map after resection of the main tumour. The histologic nodal assessment results were used as reference standards. Of these 46 patients, 10 (20%) had a past medical history of pulmonary tuberculosis as determined by clinical or imaging studies.

Results

A total of 230 mediastinal nodal stations were evaluated in 46 patients; 5 (2%) stations in 4 (8%) patients proved to be malignant by histopathology. Mean number of lymph node stations were 5. On a per-nodal station basis, PET CT for mediastinal lymph nodes staging has sensitivity: 60%; specificity: 97%; accuracy: 96%; positive predictive value (PPV): 38%; negative predictive value (NPV): 99%.

Conclusions

Integrated PET-CT provides high specificity and high accuracy, but low sensitivity for mediastinal staging of NSCLC. 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.

Clinical trial identification

Legal entity responsible for the study

Dr. Bhim Rao Ambedkar Institute Rotary Cancer Hospital, All India Institute Medical Sciences, New Delhi

Funding

Dr. Bhim Rao Ambedkar Institute Rotary Cancer Hospital, All India Institute Medical Sciences, New Delhi

Disclosure

All authors have declared no conflicts of interest.