Multimodal Nuclear Imaging Response as a Prognostic Indicator Following Spine Stereotactic Body Radiation Therapy.

Area of Science:

• Oncology
• Radiology
• Nuclear Medicine

Background:

• Magnetic resonance imaging (MRI) is standard for spinal metastases but can be limited by non-tumor changes.
• Nuclear imaging offers functional insights to complement MRI in evaluating treatment response.
• The prognostic value of nuclear metabolic response post-spine SBRT is not well-established.

Purpose of the Study:

• To assess the utility of nuclear imaging in evaluating treatment response after spine SBRT.
• To determine the association between nuclear metabolic response and local control (LC).
• To evaluate the relationship between nuclear metabolic response and overall survival (OS).

Main Methods:

• Retrospective analysis of 53 patients with spine metastases treated with SBRT.
• Pre- and post-treatment PET or bone scans were used to assess nuclear metabolic response.
• Cox regression identified predictors of LC and OS; early vs. late metabolic responses were correlated with 2-year outcomes.

Main Results:

• 74% of patients achieved a metabolic complete response (mCR) on nuclear imaging.
• mCR was significantly associated with improved 2-year LC (97% vs. 60%) and OS (76% vs. 36%).
• mCR independently predicted better LC (HR: 12.76) and OS (HR: 4.03); early/intermediate mCR correlated with 100% LC.

Conclusions:

• Multimodal nuclear imaging provides valuable functional assessment post-spine SBRT, overcoming MRI limitations.
• Metabolic complete response is a strong, independent predictor of local control and survival.
• Prospective studies are needed to standardize protocols and guide adaptive treatment strategies.