Predictive models of toxicity in external radiotherapy: dosimetric issues

Area of Science:

• Radiation oncology
• Medical physics
• Clinical oncology

Background:

• Dose-volume modeling is crucial for predicting radiotherapy toxicity in prostate cancer.
• Individual 3D dose distributions and DVHs enable quantitative assessment of dose-volume relationships for specific endpoints.

Purpose of the Study:

• To review the current state of dose-volume modeling for acute and late toxicities in prostate cancer radiotherapy.
• To highlight the importance of correlating individual dose-volume data with clinical outcomes.

Main Methods:

• Review of existing literature on dose-volume modeling and toxicity in prostate cancer radiotherapy.
• Analysis of data from large, properly followed patient populations.
• Investigation of dose-volume histograms (DVHs) for organs at risk.

Main Results:

• Rectal bleeding shows a consistent serial-like behavior with dose-volume relationships.
• Bladder irradiation demonstrates a clear dose effect.
• Erectile dysfunction requires large prospective studies for definitive dose-volume assessment.
• Acute bowel toxicity is being modeled, with recent evidence linking intestinal cavity DVH to toxicity during whole-pelvis intensity-modulated radiotherapy.

Conclusions:

• Dose-volume modeling is essential for optimizing radiotherapy for prostate cancer.
• Understanding organ-specific dose-volume effects aids in developing optimal dose constraints.
• Further research, particularly prospective studies, is needed for certain endpoints like erectile dysfunction and acute bowel toxicity.