Correlation of PET-CT, Endobronchial Ultrasound Cytology and Surgical Biopsy in Patients with Non-Small Cell Lung...

Non-small cell lung cancer (NSCLC) is the leading cause of cancer mortality worldwide. The recommended approach for mediastinal staging is a combination of both positron emission tomography- computed tomography (PET-CT) and endobronchial ultrasound (EBUS). Data on the correlation of PET-CT uptake to EBUS cytology and surgical lymph node biopsy is scarce.

Of 379 patients diagnosed with NSCLC, 65 underwent preoperative PET-CT, EBUS, and surgical lymph node biopsies. The correlations between EBUS cytology, fluoro-deoxy glucose (FDG) uptake (SUVmax) by PET-CT, and surgical biopsy were analyzed.

About 229 lymph nodes derived from 65 patients were sampled, of which 67 lymph nodes had data from EBUS, PET-CT, and surgical biopsy. 58 nodes were negative in all modalities; 6 were malignant on EBUS but negative on surgical biopsy; 2 were malignant for both modalities; and one was EBUS negative but malignant in surgical staging. EBUS sensitivity was 89% with a negative predictive value of 98%. Six patients were upstaged after surgery due to inaccessible lymph nodes (at stations 5 and intralobar) for EBUS. No malignant lymph nodes had maximum standardized uptake (SUVmax) lower than 2.9.

EBUS has high sensitivity and specificity rates, however it misses intralobar and station 5 lymph nodes which might upstage the patient after surgery. In cases when there is a high suspicion for malignant lymph nodes inaccessible to EBUS, other invasive strategies or neoadjuvant treatment should be considered. PET-CT was shown to be accurate in ruling out but not ruling in lymph node involvement.