Pulmonary function changes after thoracoscopic lobectomy versus intentional thoracoscopic segmentectomy for early-stage non-small cell lung cancer

BACKGROUND: Thoracoscopic segmentectomy is increasingly used in the surgical treatment of early-stage non-small cell lung cancer. However, it remains unclear whether pulmonary function loss after thoracoscopic lung resection is in direct proportion to the number of resected segments, and thus intentional thoracoscopic segmentectomy has the function-preserving advantage over thoracoscopic lobectomy. METHODS: In this prospective observational study, spirometry tests were performed preoperatively and 6 months postoperatively. The observed functional loss was compared with the expected loss estimated by the segment counting method. Resection extent index was introduced as the number of resected segments to total number of segments in the corresponding lobe. Spirometry changes after thoracoscopic lobectomy and intentional thoracoscopic segmentectomy were compared using propensity score matching. RESULTS: There were 338 thoracoscopic lobectomies and 321 thoracoscopic segmentectomies. Overall, the observed pulmonary function loss after segmentectomy was significantly less than after lobectomy. But the observed functional loss was significantly greater than the expected loss after segmentectomy. And pulmonary function loss per segment resected was almost doubled after segmentectomy comparing to lobectomy. For segmentectomies with a resection extent index less than 0.5, especially single segmentectomies, pulmonary function loss was significantly less than after corresponding lobectomies. Otherwise, no significant differences in spirometry changes between lobectomies and segmentectomies were detected. CONCLUSIONS: Pulmonary function loss after thoracoscopic lung resection cannot be accurately evaluated by the number of resected segments. According to the resection extent index, intentional thoracoscopic segmentectomy may help preserve more pulmonary function than thoracoscopic lobectomy only when less than half of the corresponding lobe are resected.