Functional Impact of Sublobar Resection for Early Stage Lung Cancers

Background: The increased detection of small peripheral non-small-cell lung cancers through screening programs has renewed interest in parenchyma-sparing sublobar resection as an alternative to lobectomy. While oncologic non-inferiority has been established, the functional impact of sublobar resection remains a key consideration. Methods: We reviewed evidence from landmark randomized controlled trials, recent meta-analyses, observational studies, and updated clinical practice guidelines. Results: In the CALGB 140503 trial, sublobar resection demonstrated only a modest 2-percentage-point advantage in preserved FEV1 and FVC at 6 months compared with lobectomy, a difference considered clinically marginal in patients with normal baseline pulmonary function. A meta-analysis of five randomized controlled trials confirmed that sublobar resection was associated with significantly less reduction in postoperative lung function. A retrospective study demonstrated that segmentectomy preserved FEV1 at 84.2% of preoperative values versus 69.9% after lobectomy at one year, with particular benefit observed in elderly patients and those with COPD. Volumetric analyses showed greater contralateral compensatory lung expansion after lobectomy, partially offsetting functional differences. Notably, patient-reported outcomes, including physical function, dyspnea, and cough scores, showed no significant differences between groups up to two years postoperatively. The ERS/ESTS 2025 guideline noted that segmentectomy is associated with reduced long-term dyspnea deterioration and may improve patients' ability to tolerate subsequent treatments. Conclusions: Sublobar resection offers a statistically significant but modest advantage in spirometric lung function preservation over lobectomy for early-stage NSCLC. This benefit may be most clinically relevant in patients with compromised baseline pulmonary function, COPD, or a potential need for future treatments.