What is the role of Stereotactic Body Radiation Therapy (SBRT) in treating tumors located at or near the hilus of the lung?

From the Guidelines

Stereotactic Body Radiation Therapy (SBRT) is a viable treatment option for hilar lung tumors, particularly for patients who are medically inoperable or refuse surgery, with local control rates of 70-90% possible when properly implemented. SBRT delivers high-dose, precisely targeted radiation in fewer sessions (typically 3-5 fractions) compared to conventional radiotherapy. For hilar tumors, reduced doses of 50-60 Gy in 4-8 fractions are often recommended to minimize toxicity to nearby bronchial structures, pulmonary vessels, and the esophagus 1.

Key Considerations

• Treatment planning requires sophisticated imaging techniques including 4D-CT to account for respiratory motion and PET-CT for accurate tumor delineation 1.
• Risk-adapted approaches are essential, with treatment plans carefully designed to maintain dose constraints to critical structures while delivering therapeutic doses to the tumor 1.
• Potential complications include radiation pneumonitis, bronchial stenosis, esophagitis, and vascular damage, necessitating close monitoring during and after treatment 1.

Recommendations

• SBRT is recommended for patients with early-stage NSCLC who are medically inoperable or refuse surgery 1.
• SBRT can be safely delivered without rigid immobilization, and interventions to reduce tumor motion may be useful in selected patients 1.
• The use of a PRV margin around critical serial organs should be encouraged to minimize toxicity 1.

Conclusion is not allowed, so the answer will be ended here.

From the Research

Role of SBRT in Treating Tumors Located at or Near the Hilus of the Lung

• SBRT is a general accepted and effective treatment option for patients with early stage or medically inoperable lung cancer, including those with tumors located at or near the hilus of the lung 2, 3.
• The safety and efficacy of SBRT for ultra-central lung tumors, which include those located at or near the hilus, have been evaluated in several studies 2, 4, 3.
• These studies have shown that SBRT can achieve high local control rates, with 1- and 2-year local control rates ranging from 85% to 98% 2, 4.
• However, SBRT for ultra-central lung tumors is also associated with a risk of severe toxicity, including bronchopulmonary hemorrhage, pneumonitis, and hemoptysis 2, 4.
• The risk of toxicity can be minimized by careful patient selection, consideration of concomitant therapies, and radiotherapy plan design 4.
• Studies have also identified certain risk factors for fatal toxicity events, including anticoagulation, interstitial lung disease, endobronchial tumor, and concomitant targeted therapies 4.

Treatment Outcomes and Toxicity

• The overall survival rates at 1 and 2 years after SBRT for ultra-central lung tumors have been reported to range from 52% to 90% 2, 3.
• Severe late toxicity (>or= grade 3) has been reported in 6-21% of patients treated with SBRT for ultra-central lung tumors 2, 4.
• The most common severe toxicities reported include bronchopulmonary hemorrhage, pneumonitis, and hemoptysis 2, 4.

Comparison with Other Treatment Options

• SBRT has been compared to surgical resection for early stage lung cancer, including large cell neuroendocrine carcinoma, and has been shown to be a viable treatment alternative for patients who do not meet the criteria for surgery 5.
• However, surgical resection has been shown to have improved survival compared to SBRT for patients with early stage large cell neuroendocrine carcinoma 5.