KEY POINTS
- This structured narrative review examined post-PACIFIC evidence published from 2023–2025, integrating clinical trials and recent ASTRO, ASCO, ESTRO and ESMO data on systemic intensification, RT dose/volume modulation and organ-at-risk sparing. Concurrent chemoradiotherapy followed by durvalumab remains the reference standard for unresectable locally advanced NSCLC.
- Simply moving immunotherapy earlier has not improved outcomes consistently. PACIFIC-2, CheckMate 73L and EA5181 failed to show a clear advantage from concurrent checkpoint inhibition with chemoradiotherapy, while induction chemo-immunotherapy strategies have produced encouraging early efficacy at the cost of substantial toxicity in some studies.
- Dose escalation remains highly context-dependent. Historical conventional escalation to 74 Gy in RTOG 0617 worsened outcomes, whereas newer PET-guided strategies such as NARLAL-2 and RTEP7-IFCT-1402 improved locoregional control without an obvious early toxicity penalty. The optimal dose, fractionation and patient population remain unresolved.
- SABR is emerging as another escalation strategy. In the phase II START-NEW-ERA trial, 50 patients received approximately 45 Gy/5 fractions to the primary and 40 Gy/5 to involved nodes; five-year local control was 64%, overall survival 46%, and no grade ≥3 toxicity was reported. Other high-dose approaches have produced substantially more severe and occasionally fatal toxicity, particularly near central structures.
- De-escalation may be equally important. In a randomized phase II study of PET-guided CTV omission, severe respiratory events or grade ≥3 esophagitis fell from 29% to 11% without significant differences in PFS, OS or failure pattern. The REPAINT trial similarly reduced grade 3–4 lymphopenia with risk-adapted dose reduction while maintaining comparable disease outcomes.
- Cardiac and immune-system sparing are increasingly treated as treatment objectives rather than secondary dosimetric considerations. The review highlights associations between survival or toxicity and dose to the LAD, heart base, pulmonary veins, sinoatrial node, lung and thoracic vertebrae, while noting that most proposed substructure constraints still require prospective validation.
- Biomarker-guided adaptation may eventually connect these strategies. Persistent ctDNA after chemoradiotherapy is repeatedly associated with worse outcomes, and prospective studies are now testing treatment intensification for molecular residual disease and shorter consolidation for sustained molecular clearance.
CLINICAL TAKEAWAY
The next step beyond PACIFIC may not be universal treatment intensification. The field is moving toward selecting patients for dose escalation, smaller treatment volumes, organ/immune sparing or de-escalation according to anatomy, fitness and tumor biology, but most of these approaches still need prospective validation before replacing the current backbone.