Three-dimensional CT volumetry and pulmonary function outcomes after segmentectomy versus lobectomy

OBJECTIVES: Recent randomized trials have demonstrated that sublobar resection, including segmentectomy, provides non-inferior overall survival compared with lobectomy in early-stage non-small cell lung cancer. However, these trials have shown unexpectedly small differences in postoperative pulmonary function. Compensatory expansion of the residual lung may explain these limited differences. Therefore, we used three-dimensional computed tomography (3D-CT) volumetry to quantify compensatory expansion of the residual lung and clarify its role in functional preservation after segmentectomy compared with lobectomy. METHODS: This prospective observational study analyzed 51 patients who underwent segmentectomy and 64 patients who underwent lobectomy. 3D-CT volumetry was performed preoperatively and at 12 months postoperatively to quantify non-emphysematous lung volume (NELV; morphologically preserved parenchyma) and low-attenuation volume (LAV; emphysematous regions). Changes in lung volume and pulmonary function were expressed as percentages of preoperative values. Volumetric and functional outcomes were compared overall and by resected lobe. RESULTS: than lobectomy (98.7% vs. 91.5%, P=.015), despite similar volumetric preservation. CONCLUSIONS: Both procedures achieve similar outcomes through compensatory expansion, which explains the unexpectedly small functional differences observed in recent randomized trials.