Focused Neck Ultrasound and Lymph Node Sampling by Respiratory Physicians in Suspected Lung Cancer

Background: Malignant cervical lymphadenopathy in the setting of lung cancer represents N3 disease, and neck ultrasound (NUS) with sampling is described in the Royal College of Radiologists ultrasound training curriculum for the non-radiologists. This study reviews the incorporation of NUS +/- biopsy in the routine practice of a lung cancer fast-track clinic in the UK. Methods: We retrospectively assessed 29 months of activity of a lung cancer fast-track clinic. Systematic focused NUS was conducted in suspected thoracic malignancy, sampling nodes with a ≥5-mm short axis, under real-time US using a linear probe (5-12 Mhz). Fine-needle aspirations (FNAs) with or without 18 Ga core biopsies were taken. Results: Between August 2017 and December 2019, of 152 peripheral lymph nodes (LNs)/deposits sampled, 98 (64.5%) were supraclavicular fossa LNs with median [IQR] size 12 [8-18] mm. Core biopsies were performed in 54/98 (55%) patients, while all patients had FNAs. No complications occurred. The representative yield was 90/95 (94.7%) in cases with suspected cancer. No difference was seen between FNA versus core biopsy (p = 0.44). Of the 5 non-diagnostic samples, one was FNA only. The commonest diagnosis was lung cancer in 66/98 (67.3%). PDL-1 was sufficient in 35/36 tested (97.2%). ALK-FISH was successful in 24/25 (96%) cases. EGFR mutation analysis was successful in 28/31 (90.3%) cases. Median time from clinic to initial diagnosis was 7 [5-10] days. Computed tomography (CT) scans reported no significant lymphadenopathy in 18/96 (18.7%) cases, yet 10/18 (55.5%) cases were positive for malignancy. Conclusion: Neck nodal sampling by respiratory physicians was safe, timely, with a high diagnostic yield and suitability for molecular testing. Neck US can provide a timely diagnosis in cases that may be missed by CT alone.