Stereotactic radiation therapy of brain metastases from colorectal cancer: A single institution cohort

Abstract Purpose The brain remains an uncommon site of colorectal cancer metastases. Due to the improvement of overall colorectal cancer patient survival, the incidence of brain metastases will likely rise. We report the efficacy and safety of hypofractionnated stereotactic radiation therapy and stereotactic radiosurgery, and its role in colorectal cancer brain metastasis management. Methods and material Between June 2010 and December 2014, fifteen consecutive patients received hypofractionnated stereotactic radiation therapy or stereotactic radiosurgery as first local therapy or following surgical removal for colorectal cancer brain metastases. The primary endpoint was overall survival. Secondary endpoints were brain progression free survival, in field control rates and safety. Results Median follow-up was 41 months (95% confidence interval [CI]: [8.9–73.1 months]), median overall survival was 8 months (95% CI [4.7–11.3 months]), and median brain progression-free survival was 5 months (95% CI [3.9–6.1 months]). Five in field recurrences were observed, which makes a control rate per metastases at 6 and 12 months of 77.8% (95% CI [74.34%–81.26%]), 51.9% (95% CI [44.21%–59.59%]) respectively. Over the 19 treatment sequences, five in field recurences were observed: 6, 12 and 18 months control rate per treatment sequence were 93.3% (95% CI [90.42%–96.18%]), 68.1% (95% CI [62.03%–74.17%]) and 45.4% (95% CI [36.14%–54.66%]) respectively. Immediate tolerance was good with no toxicity grade III or more. Long-term toxicity included two radionecrosis among which, one was symptomatic. Discussion The results of this retrospective analysis suggest that hypofractionnated stereotactic radiation therapy and stereotactic radiosurgery are effective and safe treatment modalities for single and multiple small brain metastases from colorectal cancer. However, results need to be confirmed by multicenter, collected data.