What is the recommended approach to radiotherapy planning for locally advanced non-small cell lung cancer (NSCLC)?

Radiotherapy Planning for Locally Advanced Non-Small Cell Lung Cancer (NSCLC)

For locally advanced NSCLC, definitive concurrent chemoradiotherapy with a radiation dose of 60 Gy in 2.0 Gy fractions delivered using intensity-modulated radiation therapy (IMRT) technique is the recommended standard approach to maximize survival outcomes while minimizing toxicity. 1

Radiation Dose and Fractionation

• Definitive thoracic radiotherapy should be no less than the biological equivalent of 60 Gy in 2.0 Gy fractions for patients receiving concurrent chemoradiotherapy 1
• Attempts at dose escalation beyond 60 Gy (e.g., to 74 Gy) have not shown survival benefit and may be detrimental 1
• For patients who cannot receive concurrent chemoradiotherapy, sequential chemoradiotherapy is recommended with accelerated radiotherapy schedules to improve outcomes 1
• In non-concurrent (sequential) schedules, radiotherapy delivered in a shorter overall treatment time is preferred, such as 66 Gy in 24 fractions 1
• For patients receiving radiation alone (without chemotherapy), modest hypofractionation from 2.15 to 4 Gy per fraction may be considered 1

Radiation Technique

• IMRT is strongly recommended over 3D conformal radiotherapy (3D-CRT) for locally advanced NSCLC 1, 2, 3
• IMRT is associated with:
  • Lower rates of severe (≥ grade 3) pneumonitis (3.5% vs 7.9%) 2
  • Reduced cardiac doses, particularly heart V40 2, 3
  • Better dose conformity to target volumes 4
  • Similar long-term survival outcomes compared to 3D-CRT 3
• Heart V40 <20% is associated with better overall survival (median 2.5 years vs 1.7 years) 3

Treatment Planning Considerations

• Accurate locoregional staging is essential before planning radiotherapy 1
• High-dose radiotherapy should be delivered according to quality standards such as those of the EORTC 1
• When planning radiation therapy, prioritize:
  • Minimizing lung V20 (associated with pneumonitis risk) 2, 3
  • Minimizing heart doses, particularly V20-V60 3
  • Note that lung V5 has not been associated with survival outcomes and should not be a contraindication for treatment 3

Special Clinical Scenarios

• For elderly patients or those with clinically relevant comorbidities, sequential chemoradiotherapy is a reasonable alternative to concurrent treatment 1
• In these patients, adding low-dose daily carboplatin to radiotherapy can improve median survival 1
• For resectable locally advanced NSCLC, especially single nodal stage N2 disease, both definitive chemoradiotherapy and induction therapy followed by surgery are options 1
• Postoperative radiotherapy (PORT) may be considered for patients with completely resected NSCLC with N2 nodal involvement, preferably after completion of adjuvant chemotherapy 1
• PORT is indicated after incomplete surgery (R1 or R2 resection) 1

Follow-up After Treatment

• Follow-up visits every 3-6 months are recommended during the first 2-3 years, then annually thereafter 1
• Follow-up should include history, physical examination, and chest CT 1
• Patients should be monitored for treatment-related complications, detection of treatable relapse, or occurrence of second primary lung cancer 1
• Smoking cessation should be offered to all patients as it leads to superior treatment outcomes 1

Common Pitfalls to Avoid

• Avoid excessive radiation dose to critical structures, particularly heart and lungs, which can lead to increased morbidity and mortality 1, 3
• Do not attempt dose escalation beyond 60 Gy in concurrent chemoradiotherapy settings outside clinical trials 1
• Avoid using 3D-CRT when IMRT is available, as IMRT reduces toxicity without compromising tumor control 2, 3
• Do not use consolidation treatment (e.g., docetaxel or EGFR-TKIs) after concurrent chemoradiotherapy as it is not recommended 1