Brain metastases from primary colorectal cancer: is radiosurgery an effective treatment approach? Results of a multicenter study of the radiation and clinical oncology Italian association (AIRO)

OBJECTIVES: The prognosis of brain metastatic colorectal cancer patients (BMCRC) is poor. Several local treatments have been used, but the optimal treatment choice remains an unresolved issue. We evaluated the clinical outcomes of a large series of BMCRC patients treated in several Italian centers using stereotactic radiosurgery (SRS). METHODS: 185 BMCRC patients for a total of 262 lesions treated were evaluated. Treatments included surgery followed by post-operative SRS to the resection cavity, and SRS, either single-fraction, then hypofractionated SRS (HSRS). Outcomes was measured in terms of local control (LC), toxicities, brain distant failure (BDF), and overall survival (OS). Prognostic factors influencing survival were assed too. RESULTS: The median follow-up time was 33 months (range 3-183 months). Surgery plus SRS have been performed in 28 (10.7%) cases, SRS in 141 (53.8%), and HSRS in 93 (35.5%). 77 (41.6%) patients received systemic therapy. The main total dose and fractionation used were 24 Gy in single fraction or 24 Gy in three daily fractions. Local recurrence occurred in 32 (17.3%) patients. Median, 6 months,1-year-LC were 86 months (95%CI 36-86), 87.2% ± 2.8, 77.8% ± 4.1. Median,6 months,1-year-BDF were 23 months (95%CI 9-44), 66.4% ± 3.9, 55.3% ± 4.5. Median,6 months,1-year-OS were 7 months (95% CI 6-9), 52.7% ± 3.6, 33% ± 3.5. No severe neurological toxicity occurred. Stage at diagnosis, Karnofsky Performance Status (KPS), presence and number of extracranial metastases, and disease-specific-graded-prognostic-assessment (DS-GPA) score were observed as conditioning survival. CONCLUSION: SRS/HSRS have proven to be an effective local treatment for BMCRC. A careful evaluation of prognostic factors as well as a multidisciplinary evaluation is a valid aid to manage the optimal therapeutic strategy for CTC patients with BMs. ADVANCES IN KNOWLEDGE: The prognosis of BMCRC is poor. Several local treatments was used, but optimal treatment choice remains undefined. Radiosurgery has proven to be an effective local treatment for BMCRC. A careful evaluation of prognostic factors and a multidisciplinary evaluation needed.