Prognostic significance of blood and lymphatic vessel invasion in pathological stage IA lung adenocarcinoma in the 8th edition of the TNM classification

•Positive blood and lymphatic vessel invasion collectively represented TVI.•TVI was a prognostic factor in Stage IA1-2 lung adenocarcinoma patients.•TVI did not affect the prognosis of Stage IA3 adenocarcinoma patients.•Stage IA1 adeno without TVI can possibly be classified as minimally invasive. The prognostic significance of blood and lymphatic vessel invasion in the 8th edition of the Tumor, Node, Metastasis (TNM) classification remains unclear. Therefore, this study aimed to evaluate the prognostic significance of blood and lymphatic vessel invasion in p-stage IA lung adenocarcinoma in the 8th edition of the TNM classification. We retrospectively examined patients with p-Stage 0-IA lung adenocarcinoma, reclassified according to the 8th edition of the TNM classification. Blood and lymphatic vessel invasion were evaluated using hematoxylin-eosin and Elastica van Gieson and hematoxylin-eosin and anti-podoplanin antibody staining, respectively. Combined blood and lymphatic vessel invasion constituted tumor vessel invasion (TVI). Overall, 306 patients were evaluated. The median follow-up period was 98.0 (range: 10–216) months. The 5-year recurrence-free survival differed significantly among patients with and without TVI in p-stage IA1 (TVI−: 100%, TVI+: 88.9%, P = 0.007) and IA2 (TVI−: 94.6%, TVI+: 80.8%, P = 0.012) but not in p-stage IA3 (TVI−: 66.7%, TVI+: 75.0%, P = 0.598). The 5-year lung cancer-specific survival also differed significantly among those with and without TVI in p-stage IA1 (TVI−: 100%, TVI+: 88.9%, P