Brain MRI Scan with Metastasis Growth

Brain Metastasis Growth: What You Need to Know About Preradiosurgical Imaging

Q: What is the primary goal of using Stereotactic Radiation Surgery (SRS) for brain metastases, and how does it differ from Whole Brain Radiation Therapy (WBRT)?

The primary goal of using Stereotactic Radiation Surgery (SRS) for brain metastases is to manage a limited number of brain metastases while mitigating the neurocognitive side effects associated with Whole Brain Radiation Therapy (WBRT). SRS allows for precise targeting of tumors, whereas WBRT involves irradiating the entire brain. SRS is favored because of its ability to deliver high doses of radiation directly to the tumor while minimizing exposure to healthy brain tissue, potentially leading to better outcomes and fewer side effects compared to WBRT.

Q: How does the timing of Magnetic Resonance Imaging (MRI) scans in relation to Stereotactic Radiation Surgery (SRS) affect the treatment of brain metastases?

The timing of Magnetic Resonance Imaging (MRI) scans is crucial in Stereotactic Radiation Surgery (SRS) for brain metastases. The study emphasizes that the time interval between the pretreatment MRI and the SRS planning MRI can impact the precision of treatment due to potential interval metastasis growth. The study, led by Michael A. Garcia and colleagues, found a significant association between the time interval between pretreatment and treatment MRI and metastasis growth. This suggests that longer intervals may necessitate adjustments in treatment planning to account for tumor growth. Fixed-frame SRS with same-day MRI planning helps to mitigate the risk to local control.

Q: What were the key findings regarding brain metastasis growth rates in the study, and what do they imply for treatment planning?

The study revealed a mean brain metastasis growth rate of 0.02 ml/day, leading to a 1.35-fold volume increase at 14 days. This means that over time, the size of the brain metastases can increase. A key implication of these findings is that the time between the pretreatment MRI and SRS delivery matters. It emphasizes the importance of considering individual factors such as time interval, tumor size, and histology to personalize treatment planning. The study highlighted that the time between MRI scans correlated with the amount of margin needed to target the entire brain metastasis volume on the day of SRS.

Q: How does the use of fixed-frame SRS with same-day MRI planning impact the local control of brain metastases?

The study found that local control (LC) was not compromised when patients received fixed-frame SRS with same-day MRI planning. This is a critical finding because it suggests that by conducting the SRS planning MRI on the same day as the treatment, clinicians can effectively account for any recent growth of the brain metastases. The use of fixed-frame SRS with same-day MRI planning allows for precise targeting of tumors and mitigates the risk of missing any tumor growth that may have occurred since the pretreatment MRI.

Q: Besides the time interval between MRI scans, what other factors were found to influence the required margins in Stereotactic Radiation Surgery (SRS) for brain metastases?

Besides the time interval between MRI scans, the study found that metastasis volume on the pretreatment MRI and melanoma histology also influenced the required margin in Stereotactic Radiation Surgery (SRS). Larger metastases at the time of the pretreatment MRI would likely require a larger margin to ensure complete coverage during SRS. Additionally, the type of cancer, specifically melanoma histology, also played a role. These factors highlight the importance of personalizing treatment planning and accounting for individual tumor characteristics and cancer types to optimize outcomes in Stereotactic Radiosurgery for brain metastases, ultimately improving patients' quality of life.

Jordan Keane in Health & Wellness December 2025 • 4 min read.

"Uncover how preradiosurgical magnetic resonance imaging (MRI) impacts brain metastasis growth and the implications for treatment planning."

Brain metastases represent a significant health challenge, contributing to morbidity and mortality in individuals with advanced cancer. To mitigate the neurocognitive side effects associated with whole brain radiation therapy (WBRT), stereotactic radiation surgery (SRS) has become an increasingly favored approach for managing a limited number of brain metastases.

SRS allows for precise targeting of tumors, but its success depends on accurate imaging. Traditionally, fixed-frame SRS involves same-day MRI planning to ensure accuracy. However, frameless SRS often requires planning MRI to be conducted days or weeks before treatment, potentially impacting the precision due to interval metastasis growth.

A key question arises: does the time lag between the planning MRI and SRS delivery affect local control (LC) due to potential tumor growth? Addressing this concern, a study published in Practical Radiation Oncology sought to quantify brain metastasis growth on MRI scans leading up to SRS, evaluating the need for CTV margins to account for such growth.

Decoding Brain Metastasis Growth: Key Insights from Preradiosurgical MRI

The study, led by Michael A. Garcia and colleagues, retrospectively reviewed data from 165 patients with 411 brain metastases treated with fixed-frame SRS between 2010 and 2013. The researchers compared pretreatment diagnostic brain MRI with SRS-planning MRI scans to quantify volumetric changes in metastases. This comparison allowed for the calculation of growth rates and the determination of minimum margins needed to encompass the entire metastasis on the day of SRS.

The findings revealed several critical insights:

Time Matters: A significant association was found between the time interval between pretreatment and treatment MRI and metastasis growth (P < .001).
Growth Rate: The mean growth rate was 0.02 ml/day, leading to a 1.35-fold volume increase at 14 days.
Margin Matters: The time between MRI scans correlated with the amount of margin needed to target the entire brain metastasis volume on the day of SRS (P < .001).
Additional Factors: Metastasis volume on the pretreatment MRI (P < .001) and melanoma histology (P < .001) also influenced the required margin.
Local Control: Local control (LC) was not compromised when patients received fixed-frame SRS with same-day MRI planning.

The results indicated that while time between pretreatment MRI and SRS is associated with brain metastasis growth, the risk to local control is mitigated with same-day MRI planning in fixed-frame SRS.

The Future of SRS Planning: Personalizing Margins for Optimal Outcomes

In conclusion, while brain metastasis growth between pretreatment MRI and SRS delivery is a valid concern, it does not compromise local control when employing fixed-frame SRS with same-day MRI planning. The study highlights the importance of considering individual factors such as time interval, tumor size, and histology to personalize treatment planning. By accounting for these variables, clinicians can optimize outcomes in stereotactic radiosurgery for brain metastases, ultimately improving patients' quality of life.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1016/j.prro.2018.06.004, Alternate LINK

Title: Brain Metastasis Growth On Preradiosurgical Magnetic Resonance Imaging

Subject: Radiology, Nuclear Medicine and imaging

Journal: Practical Radiation Oncology

Publisher: Elsevier BV

Authors: Michael A. Garcia, Mekhail Anwar, Yao Yu, Sai Duriseti, Bryce Merritt, Jean Nakamura, Christopher Hess, Philip V. Theodosopoulos, Michael Mcdermott, Penny K. Sneed, Steve E. Braunstein

Published: 2018-11-01

Everything You Need To Know

What is the primary goal of using Stereotactic Radiation Surgery (SRS) for brain metastases, and how does it differ from Whole Brain Radiation Therapy (WBRT)?

The primary goal of using Stereotactic Radiation Surgery (SRS) for brain metastases is to manage a limited number of brain metastases while mitigating the neurocognitive side effects associated with Whole Brain Radiation Therapy (WBRT). SRS allows for precise targeting of tumors, whereas WBRT involves irradiating the entire brain. SRS is favored because of its ability to deliver high doses of radiation directly to the tumor while minimizing exposure to healthy brain tissue, potentially leading to better outcomes and fewer side effects compared to WBRT.

How does the timing of Magnetic Resonance Imaging (MRI) scans in relation to Stereotactic Radiation Surgery (SRS) affect the treatment of brain metastases?

The timing of Magnetic Resonance Imaging (MRI) scans is crucial in Stereotactic Radiation Surgery (SRS) for brain metastases. The study emphasizes that the time interval between the pretreatment MRI and the SRS planning MRI can impact the precision of treatment due to potential interval metastasis growth. The study, led by Michael A. Garcia and colleagues, found a significant association between the time interval between pretreatment and treatment MRI and metastasis growth. This suggests that longer intervals may necessitate adjustments in treatment planning to account for tumor growth. Fixed-frame SRS with same-day MRI planning helps to mitigate the risk to local control.

What were the key findings regarding brain metastasis growth rates in the study, and what do they imply for treatment planning?

The study revealed a mean brain metastasis growth rate of 0.02 ml/day, leading to a 1.35-fold volume increase at 14 days. This means that over time, the size of the brain metastases can increase. A key implication of these findings is that the time between the pretreatment MRI and SRS delivery matters. It emphasizes the importance of considering individual factors such as time interval, tumor size, and histology to personalize treatment planning. The study highlighted that the time between MRI scans correlated with the amount of margin needed to target the entire brain metastasis volume on the day of SRS.

How does the use of fixed-frame SRS with same-day MRI planning impact the local control of brain metastases?

The study found that local control (LC) was not compromised when patients received fixed-frame SRS with same-day MRI planning. This is a critical finding because it suggests that by conducting the SRS planning MRI on the same day as the treatment, clinicians can effectively account for any recent growth of the brain metastases. The use of fixed-frame SRS with same-day MRI planning allows for precise targeting of tumors and mitigates the risk of missing any tumor growth that may have occurred since the pretreatment MRI.

Besides the time interval between MRI scans, what other factors were found to influence the required margins in Stereotactic Radiation Surgery (SRS) for brain metastases?

Besides the time interval between MRI scans, the study found that metastasis volume on the pretreatment MRI and melanoma histology also influenced the required margin in Stereotactic Radiation Surgery (SRS). Larger metastases at the time of the pretreatment MRI would likely require a larger margin to ensure complete coverage during SRS. Additionally, the type of cancer, specifically melanoma histology, also played a role. These factors highlight the importance of personalizing treatment planning and accounting for individual tumor characteristics and cancer types to optimize outcomes in Stereotactic Radiosurgery for brain metastases, ultimately improving patients' quality of life.