Segmentectomy Versus Lobectomy for Non-Small Cell Lung Cancers: Clinical Evidence
Four decades ago, the very first patients were enrolled into the Lung Cancer Study Group. It was a randomized, controlled trial that compared lobectomy to limited resection for biopsy-proven T1N0 non-small cell lung cancer (NSCLC). The results of this study were published in 1995. They demonstrated a three-fold increase in loco-regional recurrence and a 30 percent increase in overall death for patients who underwent limited resections (1).
In Western nations, lobectomy became the undisputed standard of care for resectable NSCLC. In Japan, there remained an ongoing interest in anatomical segmentectomies for small peripheral lung cancers, especially those with a ground-glass opacity (GGO) component. A systematic review and meta-analysis published in 2016 identified fifty-four studies that compared lobectomy procedures to sublobar resections (2). When studies were limited to lobectomies versus segmentectomies in an intentionally selected patient cohort, all six identified studies originated from Japan (3–8). A comprehensive meta-analysis of these six studies concluded no significant differences in overall or disease-free survival between the segmentectomy and lobectomy arms (2).
More recently, an extraordinary effort between the Japanese Clinical Oncology Group and the West Japan Oncology Group led to the completion of the JCOG 0802 trial. The trial included 1,106 patients with peripheral NSCLC ≤ 2cm who were randomized to either lobectomy (n = 554) or segmentectomy (n = 552) (9,10). The primary endpoint of the study was overall survival. After a 7.3-year median follow-up, patients who underwent segmentectomy were found to have a superior five-year overall survival rate compared to lobectomy survival rates: 94.3% versus 91.1% (p = 0.0082).
Interestingly, locoregional recurrence appeared to increase after segmentectomy compared to lobectomy (6.9% versus 3.1%). The lower rate of overall survival in the lobectomy group could have been attributed to a higher number of patients who died from a second cancer. Another surprising finding from the trial included the relatively modest improvement in forced expiratory volume in one second (FEV1) after segmentectomy compared to lobectomy; a 3.5% difference when measured one year after surgery.
Regarding postoperative outcomes, the participating institutions should be congratulated on a mortality rate of 0% in both surgical arms. Patients who underwent segmentectomies were found to have a higher rate of Grade ≥2 air leak and reinsertion of chest tube. Yet, other perioperative outcomes were similar between the two groups.
Based on the results of the JCOG 0802 study, there is now robust clinical evidence to justify a paradigm shift toward anatomical segmentectomies rather than lobectomies for selected patients with early stage NSCLC. Clinical implications of this new evidence may be further strengthened by the CALGB/Alliance 140503 trial if oncological outcomes are found to be similar between the lobectomy group and the sublobar resection group (11). However, it should be noted that more than half of the patients in the sublobar arm underwent wedge resections rather than anatomical segmentectomies in the CALGB study.
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