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

OBJECTIVES: Recent randomized trials have demonstrated that sublobar resection, including segmentectomy, provides noninferior 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 3-dimensional computed tomography volumetry to quantify compensatory expansion of the residual lung and clarify its role in functional preservation after segmentectomy compared with lobectomy. METHODS: In this prospective observational study we analyzed 51 patients who underwent segmentectomy and 64 patients who underwent lobectomy. Three-dimensional computed tomography volumetry was performed preoperatively and at 12 months postoperatively to quantify nonemphysematous lung volume (NELV; morphologically preserved parenchyma) and low-attenuation volume (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.