Stereotactic radiosurgery for brain metastases from colorectal cancer.

Purpose: The development of brain metastases represents an ominous event for patients with colorectal cancer. We evaluated results following stereotactic radiosurgery (SR) for patients with metastatic colorectal cancer to identify efficacy of SR and prognostic factors for survival.

Methods: This is a retrospective study of 60 brain metastases from colorectal cancer in 35 consecutive patients who underwent SR from January 1993 to December 1996. Thirteen patients also underwent additional whole-brain radiation therapy (WBRT). The median dose delivered to the tumor margin was 20 Gray (range 16-28 Gy), in most cases the tumor enclosing the 50% isodose (range 40-60%). Patients were classified into two groups: SR with and SR without WBRT. Univariate and multivariate testing was performed to determine significant prognostic factors.

Results: The median survival time was 6 months after SR and 40 months after diagnosis of primary tumor. A Karnofsky performance scale >70 was a significantly favorable prognostic factor in uni- and multivariate testing. Post-SR imaging was evaluated in 32 patients and in 54 cerebral lesions. Local tumor control was revealed in 94% of patients and 96% of treated tumors. Two patients developed local recurrences, and remote brain disease was revealed in five. No patient experienced a new focal neurologic deficit due to SR. The addition of WBRT to SR did not improve survival and local tumor control rates. Distant control rate was borderline in univariate analysis and significantly improved for patients who received additional WBRT in multivariate analysis.

Conclusion: SR for brain metastases from colorectal cancer results in a high local tumor control rate of 94% associated with few complications and therefore provides patients with a higher quality of their remaining life.