Accelerated Immuno Chemoradiotherapy Using FDG-PET/CT in Locally Advanced NSCLC

Overview

This phase II multicenter trial protocol evaluates an accelerated chemoradiotherapy regimen guided by FDG-PET/CT imaging for patients with locally advanced non-small cell lung cancer (NSCLC). The approach aims to improve tumor targeting, reduce treatment duration, and enhance transition rates to consolidation immunotherapy, potentially improving outcomes.

Background

Non-small cell lung cancer (NSCLC) accounts for the majority of lung cancer cases and often presents as locally advanced (stage III) disease. Standard treatment for unresectable stage III NSCLC includes concurrent or sequential chemoradiotherapy (CRT) followed by consolidation immunotherapy with durvalumab, which has improved survival but still faces challenges such as treatment toxicity and progression. FDG-PET/CT imaging has enhanced radiotherapy planning by more accurately defining tumor volumes, allowing for targeted treatment and potential dose escalation without increasing toxicity. Hypofractionated, accelerated radiotherapy schedules offer a promising strategy to shorten CRT duration and improve patient compliance, facilitating timely consolidation immunotherapy.

Data Highlights

Globally, lung cancer caused over 1.7 million deaths in 2020, with NSCLC comprising 80–90% of cases. Approximately 25% of NSCLC patients present with stage III disease. Real-world data indicate that 50–68% of patients proceed to consolidation durvalumab after CRT, but about 45% still progress or die within one year. The PET-Plan trial demonstrated improved locoregional control using FDG-PET/CT-based target volumes without increased out-field recurrences. Hypofractionated radiotherapy schedules delivering doses >2.2 Gy per fraction have shown feasibility with comparable toxicity.

Key Findings

• NSCLC is the leading cause of cancer mortality worldwide, with stage III disease representing a significant treatment challenge.
• Concurrent or sequential CRT followed by durvalumab consolidation is the current standard for unresectable stage III NSCLC.
• FDG-PET/CT integration improves radiotherapy target volume delineation, enabling more precise treatment and potential dose escalation.
• Hypofractionated, accelerated radiotherapy may reduce treatment duration and toxicity, improving patient compliance and transition to immunotherapy.
• Systemic inflammation biomarkers like neutrophil-lymphocyte ratio (NLR) and advanced lung cancer inflammation index (ALI) correlate with prognosis and immunotherapy response but require prospective validation.
• Despite advances, nearly half of patients progress or die within one year after consolidation immunotherapy, highlighting the need for optimized treatment strategies.

Clinical Implications

Incorporating FDG-PET/CT into radiotherapy planning allows for more accurate tumor targeting, potentially reducing toxicity and improving local control. Accelerated hypofractionated CRT regimens may shorten treatment duration, enhancing patient adherence and increasing the likelihood of receiving consolidation immunotherapy. Monitoring systemic inflammation markers could aid in prognostication and treatment personalization once validated in prospective studies.

Conclusion

The PACCELIO trial protocol proposes an innovative approach combining FDG-PET/CT-guided accelerated chemoradiotherapy with consolidation immunotherapy to improve outcomes in locally advanced NSCLC. This strategy addresses current limitations in treatment duration, toxicity, and patient selection, aiming to enhance survival and quality of life.

References

1. Sung et al. 2021 -- Global Cancer Statistics 2020
2. PACIFIC Trial Investigators 2017 -- Durvalumab after Chemoradiotherapy in Stage III NSCLC
3. Nestle et al. 2016 -- PET-Plan Trial on FDG-PET/CT in Radiotherapy Planning
4. Vansteenkiste et al. 2018 -- Hypofractionated Radiotherapy in NSCLC
5. Ethier et al. 2017 -- Systemic Inflammation Biomarkers in NSCLC