Comparing the prognostic implications of spread through airspaces versus lymphovascular invasion in non-small cell lung cancer.

Abstract

e20509 Background: Risk stratification for patients with non-small cell lung cancer (NSCLC) has historically been evaluated using TNM staging, but there are several other pathological features that have been identified as poor prognostic factors such as lymphovascular invasion, visceral pleural invasion, micropapillary pattern, and more recently, spread through airspaces. There is considerable data linking lymphovascular invasion to poor prognosis and emerging data suggesting spread through airspaces as a poor prognostic factor, but there is limited data comparing the prognostic power of lymphovascular invasion to spread through airspaces. This study aims to distinguish lymphovascular invasion from spread through airspaces as a prognostic factor and to further investigate the correlation of these to other pathologic markers. Methods: Retrospective review of the histopathologic diagnosis, recurrence, and survival status of 720 patients who underwent surgical excision of NSCLC between 2015 and 2019 was conducted. The relationships between pathological factors and prognosis were evaluated with chi square tests and a binary logistic regression was performed. Patients with stage V disease and those treated with neoadjuvant chemotherapy were excluded. Prognosis was assessed using documentation of recurrence of the primary tumor and survival status at the time of chart review. Results: Of the 720 patients, 61 patients had lymphovascular invasion (7.2%) and 56 patients had spread through airspaces (7.1%). Lymphovascular invasion was associated with a statistically significant increase in recurrence and patient mortality across stages I-III collectively, and stage I disease independently. Spread through airspaces was not associated with a statistically significant increase in recurrence or patient mortality in stage I-III or in stage I disease independently. Lymphovascular invasion was also significantly correlated to a greater number of nodal metastases, higher frequency of a micropapillary component, higher frequency of visceral pleural invasion, and increased tumor size. Spread through airspaces was significantly correlated to each of the same pathological risk factors except increased frequency of visceral pleural invasion and increased tumor size. Conclusions: The presence of lymphovascular invasion increases risk of recurrence and mortality and is associated with all of the additional pathological risk factors measured making it more relevant pathologically and prognostically than spread through airspaces.