The safety and efficacy of stereotactic radiosurgery in patients with gastrointestinal cancer brain metastasis: a systematic review and meta-analysis

Central nervous system Tumors, including metastasis, are a considerable source of morbidity and mortality. Currently, treatment options such as surgery, radiotherapy, and chemotherapy have been introduced to prevent the progression of the disease, but still, these patients do not have a good prognosis. Stereotactic radiosurgery (SRS) reduces the damage to the surroundings by focusing the radiation on the tumor tissue. In this paper, we aim to investigate the outcomes of SRS on patients with gastrointestinal-originated brain metastases. A systematic review and meta-analysis used the PRISMA guideline from inception until 27th March 2024, utilizing the relevant key terms. Records were screened and included based on pre-defined inclusion and exclusion criteria. Demanding data was extracted and analyzed using STATA v. 17. This meta-analysis of 29 studies examining SRS for brain metastases from gastrointestinal cancers revealed several significant findings. The pooled distant intracranial disease rate was 33% (95% CI: 0.21–0.45). Local tumor control rates were high, with an overall pooled rate of 88% (95% CI: 0.83–0.92). Survival outcomes showed a 6-month overall survival (OS) rate of 47% (95% CI: 0.42–0.52), decreasing to 32% at one year and 11% at two years. The 5-year OS rate was 2% (95% CI: 0.01–0.03). Subgroup analyses revealed variations in outcomes based on primary tumor site, with gastric cancer patients showing better short-term survival (73% at six months) compared to hepatic primaries (31% at six months). The 6-month progression-free survival (PFS) rate was 67% (95% CI: 0.12–1.22). Tumor control outcomes showed complete regression in 11% of cases, partial regression in 44%, stable disease in 30%, and progression in 20%. The overall mortality rate was 84% (95% CI: 0.75–0.93). This meta-analysis supports the efficacy of SRS in managing brain metastases from gastrointestinal cancers. SRS offers effective local control and may improve quality of life despite poor long-term outcomes. The high rates of distant intracranial progression underscore the need for comprehensive management strategies addressing both local and systemic disease. Future research should optimize patient selection, combine SRS with novel systemic therapies, and identify predictive biomarkers to improve outcomes in this challenging patient population.