Dose-volume effects for normal tissues in external radiotherapy: pelvis.

Area of Science:

• Radiation oncology
• Medical physics
• Clinical oncology

Background:

• Increasing use of inverse-planned intensity-modulated radiotherapy (IMRT) necessitates quantitative assessment of dose-volume relationships for organs at risk.
• Understanding late and acute toxicity is vital for optimizing radiotherapy planning.
• Significant data on dose-volume relationships for pelvic organs at risk have been gathered over the past decade.

Purpose of the Study:

• To review quantitative data on dose-volume relationships for pelvic organs at risk in prostate and other pelvic cancer radiotherapy.
• To assess the current state of knowledge regarding dose-volume or biological-based cost functions for IMRT planning.
• To identify areas where further research is needed for toxicity modeling.

Main Methods:

• Comprehensive literature review of studies published over the last 10 years.
• Analysis of quantitative information on dose-volume relationships for pelvic organs.
• Focus on organs at risk relevant to prostate and other pelvic cancer treatment planning.

Main Results:

• Dose-volume modeling for rectal toxicity shows consistent results, indicating reliable dose-volume/EUD-based constraints can be safely applied.
• Quantitative data for bladder, bowel, sexual organs, and pelvic bone marrow are less abundant but emerging.
• The rectum is the most extensively studied organ in this context.

Conclusions:

• Established dose-volume constraints for rectal toxicity provide a reliable basis for clinical application.
• Further investigation on larger patient cohorts is required for bladder, bowel, sexual organs, and pelvic bone marrow.
• Continued research is essential to refine toxicity modeling and optimize IMRT for pelvic cancers.