Several reports have shown that segmentectomy is superior to lobectomy for preservation of postoperative pulmonary function. The purpose of this study was to characterize the relationship between pulmonary function and the volume of the resected lung in patients undergoing segmentectomy or lobectomy.

Methods :Patients undergoing open lobectomy (n = 126) and open segmentectomy (n = 52) for stage I non-small cell lung cancer were analyzed retrospectively. Pulmonary function testing, including vital capacity (VC) and forced expiratory volume in 1 second (FEV₁), was performed preoperatively and at 1 and 6 months postoperatively.

Results :The postoperative reduction of VC and FEV₁, as indicated by the postoperative value/preoperative value, at 6 months after surgery was significantly less in the segmentectomy group than in the lobectomy group. However, the standardized functional loss ratio, as expressed by [(measured postoperative value)–(predicted postoperative value)] / (predicted postoperative value) × 100 (%), at 1 month after surgery was significantly lower in the segmentectomy group than in the lobectomy group. No significant difference in the standardized functional loss ratio was seen at 6 months postoperatively.

Conclusions : Pulmonary function at 6 months after surgery is better after segmental resection than after lobectomy. However, the absolute value of pulmonary function did not reach the predicted-postoperative value at 1 month after surgery. Thus, when segmentectomy is performed, clinicians should be aware that early postoperative pulmonary function may be significantly less than the expected value.