New indication for preoperative marking of small peripheral pulmonary nodules in thoracoscopic surgery.

The aim of this work was to analyze parameters to determine the possibility for detection of tumor location, and clarify the indication for preoperative marking of small peripheral pulmonary nodules in thoracoscopic resection. In a series of 97 patients who underwent video-assisted thoracoscopic surgery, information on standard uptake values (SUVs) and the detectability of tumor location was assessed. In patients whose lesions were <15 mm in diameter and where the distance to the pleura was >10 mm, lesions were not detected. Multivariate analysis to determine the factors related to the possibility of detecting tumor localization revealed that the distance to the pleural surface (P=0.0001), and the ratio of solid portion (P=0.0104) were statistically significant. In the non-solid tumor group, we should perform preoperative marking for tumors located more than 3 mm in depth from the visceral pleura. In the solid tumor group, the linear function (depth=0.4×size-0.9) may be used to separate detectable and undetectable groups. However, the sensitivity was 90.3% even if this formula was applied. Here we advocate the algorithm for detection of indication for preoperative marking using the ratio of solid portion, tumor size and SUV of fluorodeoxyglucose positron emission tomography.