Interstitial implant radiosurgery for cerebral metastases

Area of Science:

• Neurosurgery
• Radiation Oncology
• Oncology

Background:

• The role of interstitial implant radiosurgery (IRS) versus whole-brain radiation therapy (WBRT) or surgery for cerebral metastases is not well-defined.
• Stereotactic biopsy is a common diagnostic procedure for brain metastases.

Purpose of the Study:

• To compare the effectiveness of four treatment regimens for cerebral metastases: IRS with WBRT, IRS alone, WBRT alone, and IRS for recurrent metastases.
• To evaluate survival outcomes and local control rates for different treatment strategies.

Main Methods:

• Retrospective analysis of 1982-1991 data from 130 patients with cerebral metastases.
• Four treatment groups: IRS + WBRT (60 Gy), IRS alone (60 Gy), WBRT alone (40 Gy), and IRS for recurrent disease (60 Gy).
• Low-activity iodine-125 seeds used for IRS in metastases ≤ 4 cm.

Main Results:

• Combined IRS + WBRT yielded the best median survival (17 months), followed by IRS alone (12 months) and WBRT alone (7.7 months).
• IRS for recurrent metastases had a median survival of 6 months.
• Multivariate analysis indicated IRS + WBRT was not superior to IRS alone; local control was achieved in all cases with no treatment-requiring radionecrosis.

Conclusions:

• Interstitial implant radiosurgery (IRS) is an effective treatment for cerebral metastases, particularly for solitary lesions.
• IRS offers significant advantages as a minimally invasive approach for single brain metastases.
• Favorable prognostic factors include solitary metastasis and a longer interval between primary cancer diagnosis and brain metastasis detection.