LOCALIZED RT FOR BRAIN METASTASES?

In patients who had undergone surgery for brain metastases, the rate of recurrence at the resected site was similar between patients who received adjuvant whole-brain radiotherapy vs those who underwent adjuvant localized radiotherapy, according to a retrospective study by Hsieh et al in the journal Neurosurgery. However, localized radiotherapy was associated with a higher incidence of distant metastases.

Surgery followed by adjuvant whole-brain radiotherapy is a well-established treatment for brain metastases, particularly in patients who have a limited number of brain metastases. Yet discussions continue as to whether these patients require whole-brain radiotherapy or can be treated with localized radiotherapy. Localized radiotherapy is associated with fewer side effects compared with whole-brain radiotherapy, but some studies have documented an association with an increased risk for development of new intracranial metastases.

Thus, the investigators  conducted a study to examine the rate of brain metastases recurrence between patients treated with whole-brain radiotherapy vs localized radiotherapy. They also analyzed overall survival and the risk of development of leptomeningeal disease.

Study Details

Included in the study were 212 patients who underwent surgical resection for brain metastases. Patient records were obtained from the Cleveland Clinic Brain Tumor Database. The number, size, and locations of intracranial metastatic lesions were collected. The primary outcome consisted of progression of intracranial metastatic disease for each of the following: progression at the resection site, progression at nonresected sites present at the time of surgery that were treated by radiosurgery or radiotherapy, and the development of new lesions.

Of the 212 patients, 156 received whole-brain radiotherapy, and 56 received localized radiotherapy. The majority of patients (58%) were women, and the median age at the time of neurologic presentation was 58 (range = 30–83 years). The localized radiotherapy group included patients who underwent stereotactic radiosurgery or intraoperative radiotherapy.

Brain metastases most commonly originated from non–small cell lung cancer (51%), followed by breast cancer (14%) and melanoma (10%). Most patients (59%) presented with a single lesion, and 10% had more than three lesions.

Similar Outcomes on Local Tumor Control

Regardless of the patient group studied, localized radiotherapy and whole-brain radiotherapy appear to have had a similar impact on local tumor control of resected and treated (but not resected) lesions. Analysis revealed no significant difference in the rate of recurrence at the resection site (hazard ratio [HR] = 1.46, P = .26) or of unresected, radiotherapy-treated lesions (HR = 1.70, P = .41) between patients undergoing localized radiotherapy or whole-brain radiotherapy. However, whole-brain radiotherapy was more effective in controlling distant disease as well as leptomeningeal disease.

In total, 22% of all patients had a recurrence at a surgical site; 11% had a recurrence at a stereotactic radiosurgery– or radiotherapy-treated, but not surgically resected, site; 42% developed a new lesion; and 13% developed leptomeningeal disease. The median overall survival was 16.5 months and was not significantly different between the two treatment groups.

Closing Thoughts

According to the investigators, there was no statistically significant difference in the rate of tumor recurrence at resection cavities between patients treated with adjuvant whole-brain radiotherapy or localized radiotherapy. In addition, they noted no significant difference in the rate of progression of nonresected lesions in patients treated with adjuvant whole-brain radiotherapy or localized radiotherapy.

However, their research indicated a highly significant increased risk for the development of new lesions for patients treated with localized radiotherapy. They also noted that patients treated with localized radiotherapy had a significantly increased risk of the development of leptomeningeal disease.

The investigators stated, “Our results support the conclusion that adjuvant treatment with localized radiotherapy instead of whole-brain radiotherapy as adjuvant provides equivalent control at the resection cavity and radiosurgically treated lesions, with no detectable difference in overall survival.”

Michael A. Vogelbaum, MD, PhD, of the Brain Tumor and Neuro-Oncology Center, Cleveland Clinic, Cleveland, Ohio, is the corresponding author of this article in the journal Neurosurgery.

The authors reported no potential conflicts of interest.