Lymphatic permeation and vascular invasion should not be integrated as lymphovascular invasion in lung adenocarcinoma.

objectiveLymphatic permeation (LY) and vascular invasion (VI) are well-known as postoperative prognostic factors in non-small cell lung cancer (NSCLC). Some reports use the term "lymphovascular invasion (LVI)" in reference to the integration of LY and VI. The purpose in this study is to elucidate whether NSCLC with LY or VI can be labeled as LVI-positive NSCLC or it should be treated as an LY- or VI-positive tumor, respectively.

methodsWe reviewed 601 completely resected lung adenocarcinomas and squamous cell carcinomas, and examined the respective prognostic and biological significance of LY and VI.

resultsAmong 454 adenocarcinomas, multivariate survival analyses showed that LY and VI were unfavorable prognostic factors in stages II and III and stages I and II, respectively. Conversely, this relationship was not found among 147 squamous cell carcinomas. Patients with adenocarcinomas with LY and VI had a significantly worse prognosis than those with adenocarcinomas with LY or VI in stage II, but not in stage I. Among 149 recurrent adenocarcinomas, only VI had a strong effect on early recurrence and shorter post-recurrence survival. LY and VI were predictors for multiple organ recurrence of adenocarcinoma. The recurrence of adenocarcinoma with LY was high in the ipsilateral mediastinal lymph nodes, whereas VI was significantly correlated with distant metastasis to organs, such as the brain, liver, and adrenal gland.

conclusionsLY and VI have differing effects postoperative prognosis and recurrence-relevant events, suggesting that these pathological findings should not be integrated as LVI.