P3.01-031 Impact of a Novel Lung Gross Dissection Method on Intrapulmonary Lymph Node Yield: Topic: Morphology

Abstract

Incomplete retrieval of intrapulmonary lymph nodes and missed nodal metastasis are associated with worse-than-expected survival after (NSCLC) resection. We tested the nodal yield from a novel gross dissection method. Multi-institutional prospective cohort study of intrapulmonary (stations 11-14) lymph node yield from lobectomy/greater NSCLC resection specimens from 11 US hospitals from 2009-2016. A novel gross dissection protocol was used in 2 hospital pathology departments from June 2012 onwards. Intrapulmonary lymph node yields from all lobectomy or greater resections before and after the new protocol in the intervention hospitals were compared to yields from 9 non-intervention hospitals over the same time-span, using Wilcoxon-Mann-Whitney. From February 2015, some randomly selected discarded remnant lung specimens in the intervention hospitals were re-dissected for inadvertently discarded lymph nodes as a quality control measure. Intrapulmonary lymph node yields in the 2 groups of hospitals was similar at baseline, followed by a significant increase in the intervention hospitals with the novel dissection protocol (Table 1). Subsequently, in 112 specimens re-dissected for independent quality control after application of the novel dissection protocol, discarded lymph nodes were found in 30 (27%), down from 90% historically; discarded lymph nodes with metastasis in 6 (5%), down from 29% historically; and missed N1 nodal metastasis was found in 1 of 67 (1.5%) pN0 patients, down from 12% historically. The median number of missed intrapulmonary lymph nodes was 0 (down from 6 historically), the mean (standard deviation) was 0.88 (2.58). The gross dissection protocol required a median of 15 minutes (range 10 – 24). A novel gross dissection protocol significantly improves the thoroughness of intrapulmonary lymph node retrieval and can be successfully implemented in community-level pathology departments, providing a pathway for quality improvement in pathologic nodal staging of resected NSCLC.