Impact of microvascular invasion on 5-year overall survival of resected non-small cell lung cancer

Abstract

Objectives: Non-small cell lung cancer (NSCLC) is an incidental and aggressive type of cancer. Although curative treatment can be offered, the recurrence rate is relatively high. Identifying factors that have a prognostic impact may guide changes in the staging system and recommendations for adjuvant therapy. The aim of this study was to evaluate the impact of microvascular invasion on the 5-year overall survival (OS) of patients with resected NSCLC treated at a reference cancer center. Methods: This retrospective, observational cohort study included patients diagnosed with early-stage NSCLC (clinical stages I-IIIA), treated with curative-intent surgery at the Brazilian National Cancer Institute between 2010 and 2016. Results: The dataset comprised 91 surgical patients, mostly females and white, with a mean age of 62 years (range between 29-83). Cases were distributed as stages I, II, and III in 55%, 29%, and 16%. Adenocarcinoma was the predominant histological subtype (67%), and microvascular invasion was present in 25% of the patients. The 5-year OS probability was 60% (95% CI, 48.3-68.9). Among all characteristics, advanced stages (p = 0.001) and the presence of microvascular invasion (p< 0.001) were related to a worse 5-year OS. After adjusting for age group and pathological stage, the presence of microvascular invasion was associated with a 4-fold increased risk of death (HR 3.9, 95% CI, 1.9-8.2). Conclusion: The presence of microvascular invasion was an independent factor related to worse survival and, therefore, should be routinely assessed in resected specimens. Keywords: non-small cell lung cancer, thoracic surgery, survival analysis, microvascular invasion.