ASTRO: Younger Adults With a Limited Number of Brain Metastases Have Improved Overall Survival After Stereotactic Radiosurgery Alone
When treated with stereotactic radiosurgery that is not combined with whole-brain radiotherapy, adult brain cancer patients who were 50 years old and younger were found to have improved survival, according to research presented on Sunday, September 22, at the American Society for Radiation Oncology’s 55th Annual Meeting (Abstract LBA3). Younger patients (under 50 years old) were also found to be at no greater risk of new brain metastases developing despite omission of whole-brain radiotherapy.
A highly advanced brain cancer treatment, stereotactic radiosurgery utilizes precisely focused radiation beams to treat a tumor with a high dose while minimizing exposure to the surrounding healthy brain tissue. Another approach, often combined with stereotactic radiosurgery, is whole-brain radiotherapy, which is radiation therapy applied to the entire brain. This individual patient data meta-analysis was conducted on the patient data of three randomized clinical trials from North America, Europe, and Asia to evaluate the results of stereotactic radiosurgery alone compared to whole-brain radiotherapy and stereotactic radiosurgery in patients with one to four brain metastases. Patients in this study received one or both types of treatments.
Study Detials
A total of 364 patients from the three randomized clinical trials were evaluated. Of those, 51% had been treated with stereotactic radiosurgery alone, and 49% with both whole-brain radiotherapy and stereotactic radiosurgery; 19% were 50 years old or younger and 60% had a single brain metastasis. Twenty-one percent of all patients had local brain failure, and 44% had distant brain failure. Eighty-six percent of the patients died during follow-up.
The analysis revealed that patients who received only stereotactic radiosurgery had a median of 10 months survival time after treatment, as opposed to 8.2 months survival time for patients who underwent whole-brain radiotherapy in addition to stereotactic radiosurgery. Overall, local brain failure occurred earlier in patients who received only stereotactic radiosurgery (6.6 months post-treatment), as opposed to patients who underwent whole-brain radiotherapy and stereotactic radiosurgery (7.4 months post- treatment). Distant brain failure was also earlier overall in patients who received only stereotactic radiosurgery, occurring at 4.5 months post-treatment, compared to 6.5 months post-treatment for patients who received both whole-brain radiotherapy with stereotactic radiosurgery.
The impact of age on treatment effectiveness revealed stereotactic radiosurgery alone results in improved overall survival in patients 50 years old and younger. For patients age 35, 40, 45, and 50, the estimated hazard ratio and the corresponding 95% confidence intervals (CI) were 0.46 (95% CI = 0.24–0.90), 0.52 (95% CI = 0.29–0.92), 0.58 (95% CI = 0.35–0.95), and 0.64 (95% CI = 0.42–0.99), respectively. With respect to distant brain failure, a significant association with age was also observed. Patients 50 years and younger were at no significantly greater risk of developing new tumors despite being treated with stereotactic radiosurgery alone.
Surprising Results
“We expected to see a survival advantage favoring combined therapy, given the additional benefits of whole brain radiation, particularly with respect to increasing local control and reducing the risk of new brain metastases,” said lead study author Arjun Sahgal, MD, an Associate Professor of Radiation Oncology at the University of Toronto and Deputy Chief of Radiation Oncology at Odette Cancer Centre, Sunnybrook Health Sciences Centre in Toronto.
“Our study indicates, however, a survival advantage for [stereotactic radiosurgery] alone in younger patients who also interestingly were observed to have no greater risk of new brain metastases despite the omission of whole-brain radiation,” Dr. Sahgal said. “This implies that [whole-brain radiotherapy] may not be required for all patients with brain metastases, particularly younger patients, and [stereotactic radiosurgery] alone should be considered as the favored first-line therapeutic option. The implications are significant as it has been shown in other studies that [whole-brain radiotherapy] is detrimental to short-term memory function and negatively impacts some aspects of patients’ quality of life.”
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
