Adaptive dose painting for prostate cancer

Area of Science:

• Radiation Oncology
• Medical Physics
• Oncology

Background:

• Dose painting (DP) is a radiation therapy (RT) strategy for heterogeneous tumors, aiming to maximize tumor control by delivering higher doses to resistant regions and lower doses to sensitive ones.
• Spatial accuracy in dose delivery is crucial for DP success, and adaptive RT (ART) workflows can mitigate geometric uncertainties.

Purpose of the Study:

• To dosimetrically compare adaptive RT (ART) and non-adaptive conventional RT workflows for delivering DP prescriptions in prostate cancer (PCa).

Main Methods:

• A planning and treatment simulation study involving four arms: adaptive and conventional workflows with DP and homogeneous dose.
• Utilized MR linac imaging data from 5 PCa patients, with local radiation sensitivity derived from apparent diffusion coefficient maps.
• DP plans were optimized for tumor control probability (TCP) maximization under rectum dose constraints, while homogeneous plans used a range of prostate doses.

Main Results:

• Accumulated DP doses in both adaptive and conventional workflows achieved high TCP (96-99%).
• Adaptive DP showed a marginal advantage over conventional DP (up to 2.6 percentage points).
• Conventional workflows exhibited potential target misses in one patient, which could compromise TCP if systematic.

Conclusions:

• Dose painting (DP) maintains or slightly increases tumor control probability (TCP) compared to homogeneous dosing.
• Adaptive DP workflows effectively avoid target misses, offering an advantage over conventional RT approaches.