[Normal tissue tolerance to external beam radiation therapy: spinal cord]

Area of Science:

• Neurology
• Oncology
• Radiotherapy

Background:

• Radiation myelopathy is a serious complication of radiation therapy.
• Its pathogenesis, involving glial and vascular injuries, is not fully understood.
• Oligodendrocytes, precursors, cytokines, and stress molecules are implicated in its development.

Purpose of the Study:

• To review the pathogenesis of radiation myelopathy.
• To describe its clinical presentation and typical latency period.
• To identify factors that alter typical features and strategies to minimize risks.

Main Methods:

• Review of animal experiments and human autopsy series.
• Analysis of recent studies on cellular and molecular mechanisms.
• Evaluation of clinical presentations and latency periods.
• Assessment of modifying factors and risk-reduction strategies.

Main Results:

• Radiation myelopathy combines glial and vascular injuries.
• Clinical symptoms are non-specific, often progressive, and life-threatening.
• Typical onset is 6 months to 2 years post-irradiation (>50 Gy).
• Factors like chemotherapy and neurotoxic drugs can alter presentation.
• Hyperfractionated regimens, dose estimation, and QA programs reduce risks.

Conclusions:

• Radiation myelopathy pathogenesis requires further research.
• Clinical presentation varies, with potential for severe outcomes.
• Risk mitigation involves careful dose management and understanding of modulating factors.