Clinical Significance and Preoperative Prediction of High-Grade Subtypes in Early-Stage Lung Adenocarcinoma Eligible for Sublobar Resection.

[BACKGROUND AND OBJECTIVES] The indication for sublobar resection is determined based on radiologic findings, but some cases exhibit radiology-pathology discordance. This study aimed to examine the impact of histologic subtypes on radiology-pathology discordance and their preoperative predictability.

[METHODS] We reviewed 585 patients with clinical stage IA adenocarcinoma and examined the relationship between radiology-pathology discordance and histologic characteristics, focusing on high-grade components: solid (SOL) or micropapillary (MIP). The predictive ability of radiologic or cytopathologic examinations for those subtypes was evaluated.

[RESULTS] Radiology-pathology discordance was found in 148 (25.2%) patients and was significantly associated with the presence of histologic high-grade components, with 71.9% and 70.4% of patients with upstaged lymph node and pleural invasion statuses having high-grade components. The preoperative prediction of high-grade components varied between subtypes, and radiographically pure-solid appearance and high maximum standardized uptake value were independent predictors of the SOL subtype, but not MIP. Among pre- or intraoperative cytopathologic examinations, intraoperative touch imprint cytology exhibited superior detection ability for MIP component.

[CONCLUSIONS] Histologic high-grade components are highly associated with radiology-pathology discordance in early-stage lung adenocarcinoma. Radiologic assessment would be beneficial for predicting the SOL subtype, but not MIP. Alternatively, intraoperative cytologic assessment would complement the detection of MIP subtype.