The American Society for Radiation Oncology (ASTRO) released a new clinical guideline designed to provide guidance on the use of radiation therapy to treat patients with brain metastases. This updates ASTRO’s original 2012 guideline to reflect recent research developments (Pract Radiat Oncol 2022; https://doi.org/10.1016/j.prro.2022.02.003).
“The ASTRO guidelines provide a comprehensive set of evidence-based recommendations that address indications for, approaches to, and toxicities of stereotactic radiosurgery (SRS) and/or whole brain radiotherapy (WBRT) for intact and resected brain metastases,” stated Vinai Gondi, MD, Director of Research and Education at the Northwestern Medicine Chicago Proton Center, and Vice Chair of the guidelines task force. “There is a focus on advanced radiation therapy techniques, such as SRS and hippocampal avoidance whole brain radiation therapy (HA-WBRT), that improve control of brain metastases and lead to fewer side effects and better quality of life outcomes.”
In announcing the new guidance, ASTRO highlighted the evidence-based recommendations the organization hopes will “guide the multidisciplinary planning and delivery of advanced radiation therapy techniques to manage intact and resected brain metastases from non-hematologic solid tumors.”
As ASTRO pointed out, radiation therapy is commonly used to manage brain metastases; prolonged survival; and provide relief from headaches, dizziness, and other neurological problems that result from brain metastases.
To reduce adverse effects of brain metastases and preserve patients’ quality of life, researchers have developed advanced radiation therapy techniques such as SRS and HA-WBRT. These treatments result in fewer side effects and deliver therapeutic doses of radiation to the tumors while limiting exposure to healthy brain tissue.
More recent developments to manage brain metastases include advances in neurosurgical care, as well as emerging systemic therapies “that may serve as alternates or adjuncts to radiation therapy and surgery,” according to ASTRO, which noted that chemotherapy has not traditionally been a common treatment for brain metastases.
In an effort to propose recommendations “to inform best clinical practices on the use of radiation therapy for brain metastases with strong emphasis on multidisciplinary care,” ASTRO convened a multidisciplinary task force including representatives from the American Association of Neurological Surgeons/Congress of Neurological Surgeons, the American Society of Clinical Oncology (ASCO), and the Society of Neuro-Oncology (SNO).
ASTRO, ASCO, and SNO also published a joint guideline that featured clinical recommendations for surgery and systemic therapy, as well as radiation therapy, for the multidisciplinary treatment of patients with brain metastases (J Clin Oncol 2022; doi: 10.1200/JCO.21.02314). This guideline update “is intended to be a complement to that joint guideline to provide more comprehensive detail about radiation therapy,” and includes the following recommendations.
Intact/Unresected Brain Metastases
- For patients with 1-4 brain metastases and reasonable performance status (ECOG performance status 0-2), SRS is recommended. For patients with 5-10 brain metastases and reasonable performance status, SRS is conditionally recommended. For patients with tumors exerting mass effect and/or larger size, multidisciplinary discussion with neurosurgery to consider surgical resection is suggested.
- For patients with symptomatic brain metastases, upfront local therapy (radiation and/or surgery) is strongly recommended. For patients with asymptomatic brain metastases who are eligible for CNS-directed systemic therapy, multidisciplinary and patient-centered decision-making to determine whether local therapy may be safely deferred is conditionally recommended.
- For patients with favorable prognosis who have brain metastases that are ineligible for surgery and/or SRS, WBRT is recommended as a primary treatment. Hippocampal avoidance is recommended when appropriate to preserve memory function, as is the addition of memantine to delay neurocognitive decline. Routine adjuvant WBRT added to SRS is not recommended.
- For patients with poor prognosis and brain metastases, WBRT may not improve outcomes compared to supportive care alone. Reasonable options for these patients include palliative care or hospice, or short-course WBRT for symptomatic brain metastases.
- Recommendations also include guidance for SRS and WBRT dosing and the use of single-fraction versus hypofractionated SRS. Additionally, while the use of SRS is driven by the number of brain metastases, it is critical that other factors, such as the patient’s total tumor volume, tumor location, age, and extracranial disease status, should be taken into consideration during patient-centered decision-making by the multidisciplinary team.
Resected Brain Metastases
- Radiation therapy is recommended for all patients following resection of brain metastases to improve intracranial control. For patients with limited brain metastases after resection, postoperative SRS is recommended over WBRT to preserve the patient’s neurocognitive function and quality of life.
- SRS prior to brain metastasis resection is conditionally recommended as a potential alternative to postoperative SRS.
“The ASTRO guidelines are meant to be helpful to the entire radiation oncology team—physicians, nurses, physicists, dosimetrists—as well as collaborating oncology specialists outside radiation oncology, such as medical oncology, neurosurgical oncology, and neuro-oncology, in complementing the recently published ASCO-SNO-ASTRO guidelines for brain metastasis management and providing the framework for multidisciplinary, patient-centered decision-making,” stated Paul D. Brown, MD, Professor of Radiation Oncology at the Mayo Clinic and Chair of the guideline task force .
Mark McGraw is a contributing writer.