Background
NCDB (National Cancer Data Base) retrospective cohort analysis. 30,552 patients with pathologically confirmed pN2 NSCLC after surgical resection (R0 or R1), treated at NCDB-participating facilities 2006–2010. Compared OS with vs without postoperative radiotherapy (PORT). PORT defined as ≥45 Gy to mediastinum delivered after surgery.
Interventions and follow up
Arm A: PORT (N≈10,564)
Arm B: No PORT (N≈19,988)
Primary endpoint: OS (5-year)
mFollow up: 5-year analysi
Arm B: No PORT (N≈19,988)
Primary endpoint: OS (5-year)
mFollow up: 5-year analysi
Results
5-yr OS: 39.3% (PORT) vs 34.8% (no PORT), HR 0.77 (95% CI 0.72–0.82), P<.001 (adjusted)
Benefit by N2 extent: Greatest benefit for microscopic/single-station pN2; no benefit for pN0-N1
PORT subgroup (pN0-1): Associated with worse OS — harm in node-negative patients
Benefit by N2 extent: Greatest benefit for microscopic/single-station pN2; no benefit for pN0-N1
PORT subgroup (pN0-1): Associated with worse OS — harm in node-negative patients
Adverse events
Main adverse events: Retrospective registry — toxicity data not systematically captured. Historical PORT literature documents increased cardiac and pulmonary morbidity with older techniques; modern IMRT-based PORT may have better therapeutic index.
Conclusions
PORT was associated with a significant survival benefit (HR 0.77) for pN2 NSCLC after resection in this large registry analysis, providing renewed support for PORT after years of controversy following the negative PORT Meta-analysis (Lancet 1998). No benefit and potential harm was seen for pN0-N1 disease.
Key Limitations
Key Limitations: Major selection bias inherent to retrospective registry analysis — clinicians selected patients for PORT based on unmeasured factors. Incomplete treatment detail (dose, technique, field, fractionation) precludes characterization of modern vs older PORT. Confounders including performance status, comorbidities, completeness of resection, and adjuvant chemotherapy use are incompletely controlled. The prospective LUNG ART trial (Pignon, Lancet Oncol 2022) subsequently showed no DFS or OS benefit for PORT with modern IMRT and increased grade ≥3 cardiac events, casting doubt on the causal inference from this registry data.
Clinical Context
The Robinson NCDB analysis revived interest in PORT for pN2 NSCLC by suggesting potential OS benefit in the modern era. However, the subsequent LUNG ART phase 3 RCT (Pignon, Lancet Oncol 2022) found no DFS benefit for PORT (HR 1.06 for DFS) and demonstrated increased cardiac toxicity. Current NCCN and ESMO guidelines do not recommend PORT routinely for completely resected pN2 NSCLC; PORT may be considered for R1 (positive margin) resection. The PORT controversy remains unresolved pending further mature data from ongoing PORT trials.
References