Abstract
OBJECTIVE: The diagnostic criteria of lymphatic vascular invasion have not been standardized. Our investigation assesses the factors associated with lymphatic vascular invasion positive tumors and the impact of lymphatic vascular invasion on overall survival for patients with non-small cell lung cancer undergoing (bi)lobectomy with an adequate node dissection. METHODS: The National Cancer Database was queried from the years 2010 to 2015 to find surgical patients who underwent lobectomy with at least 10 lymph nodes examined (adequate node dissection) and with known lymphatic vascular invasion status. Paired t tests were used to distinguish differences between the patients with and without lymphatic vascular invasion in their specimen. Multivariable analysis was used to determine factors associated with overall survival. Propensity score matching adjusting for overall survival factors was used to determine the lymphatic vascular invasion's overall survival impact by grade, histology, p-T/N/overall stage, and tumor size. RESULTS: Lymphatic vascular invasion status was reported in 91.6% and positive in 23.4% of 28,842 eligible patients. Academic medical centers, institutions with populations more than 1,000,000, and the mid-Atlantic region reported higher rates of lymphatic vascular invasion positive tumors as well as overall survival compared with other cancer centers. Lymphatic vascular invasion was independently associated with a significant decrement in overall survival as per multivariable analysis and propensity score matching. Propensity score matching demonstrated that lymphatic vascular invasion was associated with a significant decrement in overall survival for all histologies, tumor grades, tumor sizes, and stages, except for more advanced pathologic stages T3/III/N2 and larger tumors greater than 4 cm for which overall survival was trending worse with lymphatic vascular invasion positive. CONCLUSIONS: Lymphatic vascular invasion positive varies based on hospital location/type and population, but it was associated with a decrement in overall survival that was independent of pathologic T/N/overall stage, histology, and tumor grade. Lymphatic vascular invasion must be standardized and considered as a staging variable and should be considered as a sole determinant for prognosis, especially for those with earlier-stage and smaller tumors.