Tracking Growth of Brain Metastases

Background: Literature is relatively sparse on the growth rate of brain metastases. This is an important concept, given that the time delay between imaging and treatment may result in clinically significant tumor growth that could alter treatment planning. Understanding the growth rate of brain metastases is also useful in determining the value of radiation therapy for poor performance patients. This study will potentially shed light on this subject and spur further research. Methods: This qualitative study includes 21 patients treated with Gamma Knife therapy at MD Anderson of Cooper University Hospital. These 21 patients had various amounts of brain metastases, totaling 38 metastases. All patients had never received SRS or chemotherapy in the past or during the timeframe between imaging to treatment. All patients had 2 MRI imaging sets. Imaging sets were retrospectively reviewed to measure volume, size of greatest dimension, and type of lesions. Results: By size of greatest dimension, our data for all masses revealed a growth rate of 0.12mm/day (SD ± 0.23). solid lesions at 0.12mm/day (SD ± 0.17), necrotic lesions at 0.13mm/day (SD ± 0.25), and cystic lesions at 0.05mm/day. When studying growth rate in volume, all masses had an average growth rate at 0.03mL/day (SD ± 0.06), solid lesions at 0.02mL/day (SD ± 0.07), necrotic lesions at 0.04mL/day (SD ± 0.04), and cystic lesions at 0.02mL/day. Conclusion: Our results show growth between imaging sets that may have clinical significance for SRS treatment planning. Further research should be done into this subject to optimize delivery of radiation treatment