Utility of PET-CT in non-small cell lung cancer clinical stage IB-IIA according to AJCC 8th edition staging system: an alternative to invasive mediastinal staging?

Abstract

Objective: Mediastinal nodal staging in lung cancer is essential to determine treatment strategy and prognosis. There are controversies as to whether a mediastinal negative result in PET-CT may spare the invasive staging of the mediastinum. The main endpoint is to evaluate the negative predictive value (NPV) of PET-CT in non-small cell lung cancer (NSCLC) clinical stage IB-IIA without clinical nodal involvement. The secondary endpoint is to evaluate the prevalence of mediastinal and hilar nodal affection in this population. Methods:We performed an observational descriptive study from January 2010 to January 2020, including 76 patients with clinical stage IB-IIA, who underwent pulmonary resection with systematic nodal sampling (pre-determined lymph node stations based on tumour location) for primary NSCLC. Clinically, nodal involvement was defined as any lymph node greater than 1 cm in the short axis on a CT or with metabolic uptake greater than 2.5 SUV on PET-CT. The prevalence of nodal metastases was recorded.Results: Fifty six patients had clinical stage IB and 20 had clinical stage IIA. Mean tumour size was 3.74 ± 0.5 cm. Lobectomy was the resection procedure most frequently performed. Of the 76 patients with clinical N0 by PET-CT who underwent surgical resection, 10 (13.1%) were upstaged to pN1 and none were upstaged to pN2. NPV of PET-CT for overall nodal metastasis was 87% (95% CI: 0.79-0.94). NPV of PET-CT for N2 metastasis was 100%. Conclusion:PET-CT might be an alternative to invasive mediastinal staging in patients with NSCLC clinical stage IB-IIA who are surgical candidates. Further prospective multiinstitutional studies are necessary to verify the external validity of our study.

Mediastinal Staging with Endobronchial Ultrasound in Early-Stage Non—Small Cell Lung Cancer: Is It Necessary?

“…The accepted threshold for detecting 18-fluorodeoxyglucose (FDG) avidity in lymph nodes is a standardized uptake value (SUV) of ≥2.5. 16 Overall, PET/CT was shown to have a sensitivity of up to 88% and has a specificity of 96% for the clinical staging of NSCLC. 17 The improved sensitivity of PET/CT over CT imaging alone for staging is likely explained by the ability of the former to detect abnormal FDG metabolism prior to the development of any anatomic abnormalities on CT. 18 When specifically evaluating the effectiveness of PET/CT in mediastinal lymph nodes for clinical staging, PET/CT is less effective.…”