Clinical Scorecard: Prognostic Value of the Systemic Immune-Inflammation Index for Overall Survival Following Primary Stereotactic Radiosurgery in Patients with Brain Metastases

At a Glance

Key Highlights

• Brain metastases are the most common adult brain tumors with SRS as a primary local control treatment.
• SII and SIRI, derived from routine CBC with differential, are objective biomarkers linked to prognosis in various cancers but understudied in brain metastases treated with SRS.
• This study evaluates SII and SIRI as prognostic markers for overall survival and local tumor control after primary SRS.

Guideline-Based Recommendations

Diagnosis

• Use routine pre-SRS complete blood count with differential to calculate SII and SIRI as adjunct prognostic biomarkers.
• Apply Response Assessment in Neuro-Oncology Brain Metastases (RANO-BM) criteria for tumor progression assessment.

Management

• Plan SRS with a 1-mm tumor margin and prescribed dose based on fractionation schemes (e.g., 30 Gy in 3 fractions).
• Exclude patients with prior whole-brain radiation or surgical resection for the target lesion to maintain prognostic accuracy of SII/SIRI.

Monitoring & Follow-up

• Follow patients with MRI or enhanced CT post-SRS at regular intervals to assess local control and progression.
• Monitor overall survival from end of SRS to death or last follow-up, with minimum 24 months follow-up for survivors.

Risks

• Consider potential variability in subjective measures like Karnofsky Performance Status when using traditional prognostic tools.
• Recognize that active infection or inflammation at time of CBC measurement can confound SII and SIRI values.

Patient & Prescribing Data

Adults with brain metastases undergoing primary fractionated SRS without prior radiation or surgery to the lesion

Higher pre-treatment SII and SIRI values are associated with worse overall survival, suggesting their utility in risk stratification and prognosis beyond traditional clinical indices.

Clinical Best Practices

• Incorporate objective blood-based biomarkers such as SII and SIRI alongside clinical prognostic tools to improve survival prediction accuracy.
• Ensure CBC is obtained prior to initiation of systemic cancer therapy and in absence of active infection or inflammation for reliable biomarker calculation.
• Use standardized imaging and volumetric assessment methods for tumor measurement and progression evaluation post-SRS.
• Apply rigorous statistical methods including multivariable Cox regression and validation of proportional hazards assumptions when analyzing prognostic factors.

References

• Brain metastases epidemiology and treatment overview
• Systemic immune-inflammation index and systemic inflammation response index original studies
• Response Assessment in Neuro-Oncology Brain Metastases (RANO-BM) criteria
• Stereotactic radiosurgery techniques and dosing
• Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement