hyperfractionation
Pronunciation: HIGH-per-frak-shun-AY-shun
A radiation therapy schedule using smaller doses delivered multiple times per day to increase total dose while reducing late toxicity.
Full Definition
Hyperfractionation is a radiation therapy fractionation scheme that delivers smaller individual doses (typically 1.1-1.2 Gy) given twice daily with at least a 6-hour interval between treatments. This approach allows for a higher total dose to be delivered compared to conventional fractionation while potentially reducing late normal tissue toxicity. The biological rationale is based on the different repair kinetics of tumor cells versus normal tissues. Hyperfractionation is most commonly used in head and neck cancers and some brain tumors where the therapeutic window between tumor control and normal tissue complications is narrow.
Usage
Usage note: Often confused with hypofractionation which uses larger doses less frequently. Essential to specify the exact schedule when documenting treatment plans.
In Context
- "The hyperfractionation protocol delivered 1.1 Gy twice daily to a total dose of 81.4 Gy." — Radiation oncology protocol
- "Hyperfractionation showed improved local control in head and neck squamous cell carcinoma compared to standard fractionation." — Clinical trial report