Routine systematic sampling versus targeted sampling during endobronchial ultrasound: A randomized feasibility trial

Objective: Triple normal lymph nodes, appearing benign on computed tomography, positron emission tomography, and endobronchial ultrasound, have less than a 6% probability of malignancy. We hypothesized that targeted sampling (TS), which omits biopsy of triple normal lymph nodes during endobronchial ultrasound, is not an inferior staging strategy to systematic sampling (SS) of all lymph nodes.

Methods: A prospective randomized feasibility trial was conducted to decide on the progression to a pan-Canadian trial comparing TS with SS. Patients with cN0-N1 non-small cell lung cancer undergoing endobronchial ultrasound were randomized to TS or SS. Lymph nodes in the TS arm crossed over to receive SS. Progression criteria included recruitment rate (70% minimum), procedure length (no significant increase for TS), and incidence of missed nodal metastasis (<6%). Mann-Whitney U test and McNemar's test on paired proportions were used for statistical comparisons.

Results: The progression criterion of 70% recruitment rate was achieved early, triggering a planned early stoppage of the trial. Nineteen patients were allocated to each arm. The median procedure length for TS was significantly shorter than SS (3.07 vs 19.07 minutes; P < .001). After crossover analysis, 5.45% (95% confidence interval, 1.87-14.85) of lymph nodes in the TS arm were upstaged from N0 to N2, but this incidence of missed nodal metastasis was below the 6% threshold. During surgical resection, the nodal upstaging incidence from N0 to N2 was 0% for 15 lymph nodes in each arm.

Conclusions: Progression criteria to a pan-Canadian, noninferiority crossover trial comparing TS with SS have been met, and such a trial is warranted.