Stereotactic radiosurgery and hippocampal avoidance techniques are under investigation as an alternative to whole brain radiotherapy (WBRT), primarily due to their potential to reduce neurocognitive decline, helping to maintain memory and improve the quality of life for patients.
Traditionally patients with brain metastases from small cell lung cancer (SCLC) are treated with WBRT. The ENCEPHALON trial is a phase II trial that randomized patients with brain metastases from small-cell lung cancer between WBRT and stereotactic radiotherapy (SRT) with the Accuray CyberKnife® System. They found that patients receiving WBRT were at higher risk of a significant decline in neurocognitive function than patients receiving SRT. This trial expands the applicability of SRT to this population of patients and demonstrates the efficacy with which the CyberKnife System can minimize dose to healthy tissue to help reduce neurocognitive decline1.
Another study exploring the benefit of hypofractionated stereotactic radiotherapy (HFSRT) over WBRT for neurocognitive function is the ESTRON trial. This study compared post operative (HFSRT) to WBRT in patients with 1-10 brain metastases. 54 patients were randomized, and results showed that HFSRT provides excellent local control. Further follow-up is required to determine the risk of intracranial progression and neurocognitive function2.
The introduction of hippocampal-avoidant whole brain radiotherapy (HA-WBRT) has allowed improvements in short-term memory without compromising treatment efficacy. Planning HA-WBRT with VMAT can be resource-intensive and does not always meet the planning objectives. A single-institution dosimetric study compared VMAT arcs with helical delivery on the Accuray TomoTherapy® System to see if improvements in dosimetry and treatment planning time could be achieved. It was found that significant improvements in target coverage and organ at risk sparing could be achieved using the TomoTherapy System3.
References
- Bernhardt et al. (2023) Stereotactic Radiotherapy vs Whole Brain Radiaiton Therapy for Patients with 1-10 Brain Metastases from Small Cell Lung Cancer: Results of the Randomized ENCEPHALON (ARO 2018-0) Trial. ASTRO 2023
- El Shafie et al. (2023) Hypofractionated Stereotactic Radiotherapy (HFSRT) of the Resection Cavity versus Whole-Brain Radiotherapy (WBRT following Brain Metastasis Resection – Results of the ESTRON Randomized Phase 2 Trial. ASTRO 2023
- DiBartolo et al. (2023) Helical TomoTherapy Planning Technique Improves Dosimetry for Hippocampal-Avoidant Whole Brain Radiotherapy Compared with VMAT. ASTRO 2023
Accuray Incorporated as a medical device manufacturer cannot and does not recommend specific treatment approaches. Individual results may vary.