Early observations and pilot data that first suggested a new direction
The 1995 Lung Cancer Study Group (LCSG) randomized trial established lobectomy as the standard of care for stage IA NSCLC. Among 276 patients with peripheral T1N0 tumors randomized to lobectomy or limited resection (wedge or segmentectomy), the limited resection group had a three-fold increase in local recurrence without improvement in perioperative morbidity, mortality, or late pulmonary function. This trial cemented lobectomy as the benchmark for three decades, though critics noted the inclusion of wedge resections (not anatomic segmentectomy) and the absence of routine CT staging.
Landmark RCTs and pivotal trials that established the evidence base
Two landmark trials published in 2022-2023 overturned the 1995 LCSG paradigm. JCOG0802, a Japanese phase 3 trial, randomized 1,106 patients with stage IA (≤2 cm) peripheral NSCLC to segmentectomy or lobectomy. At median 7.3-year follow-up, segmentectomy demonstrated superior 5-year overall survival (94.3% vs 91.1%; both superiority and noninferiority confirmed), though locoregional recurrence was higher (10.5% vs 5.4%). CALGB 140503 (Alliance), enrolling 697 patients with similar criteria, confirmed noninferiority of sublobar resection for disease-free survival at 7-year median follow-up. Together, these trials established sublobar resection as an acceptable alternative for small peripheral tumors.
Follow-up studies, subgroup analyses, and real-world validation
The convergent findings from JCOG0802 and CALGB 140503 prompted a paradigm shift. The question evolved from whether sublobar resection was acceptable to which patients benefited most from parenchyma-sparing approaches. Segmentectomy (anatomic resection with lymph node sampling) emerged as the preferred sublobar approach over wedge resection, given better margin adequacy and lymph node assessment. The higher locoregional recurrence with segmentectomy in JCOG0802 (10.5% vs 5.4%) despite superior overall survival suggested that surveillance and salvage therapy could effectively manage recurrences.
Guidelines
Integration into clinical practice guidelines and recommendations
Following publication of JCOG0802 and CALGB 140503, NCCN guidelines incorporated anatomic segmentectomy as an acceptable alternative to lobectomy for peripheral node-negative NSCLC ≤2 cm. The recommendation specifies adequate margins (≥2 cm or ≥ tumor size) and intraoperative lymph node assessment.
NCCN
Anatomic segmentectomy acceptable for peripheral node-negative NSCLC ≤2 cm with adequate margins
ACCP
Sublobar resection (preferably segmentectomy) recommended for peripheral T1aN0 NSCLC ≤2 cm
Now
Current standard of care and ongoing research directions
Sublobar resection has become standard of care for small (≤2 cm) peripheral stage IA NSCLC based on two concordant randomized trials. The focus has shifted to patient selection refinement — identifying which tumor characteristics (ground-glass predominance, consolidation-to-tumor ratio, histologic subtype) predict the best outcomes with parenchyma-sparing surgery. The role of sublobar resection for tumors 2-3 cm remains under investigation. Robotic and thoracoscopic approaches to segmentectomy continue to evolve.
What changed to make sublobar resection acceptable after decades of lobectomy being the standard?+
Two randomized trials (JCOG0802 with 1,106 patients and CALGB 140503 with 697 patients) demonstrated that for small peripheral NSCLC ≤2 cm, sublobar resection was noninferior to lobectomy. JCOG0802 even showed superior overall survival with segmentectomy (94.3% vs 91.1% at 5 years). Modern CT screening detects smaller tumors than in 1995, and anatomic segmentectomy with systematic lymph node sampling was better standardized in these trials.
Is segmentectomy preferred over wedge resection?+
Based on the trial evidence, anatomic segmentectomy is generally preferred because it provides wider margins, includes systematic hilar and mediastinal lymph node assessment, and was the predominant approach in JCOG0802 where outcomes were best. Wedge resection was more common in CALGB 140503 and may be appropriate when segmentectomy is technically difficult, but margin adequacy (≥2 cm) becomes critical.
