Clinical iterative model development improves knowledge-based plan quality for high-risk prostate cancer with four...

Area of Science:

• Radiation Oncology
• Medical Physics
• Prostate Cancer Treatment

Background:

• Manual Volumetric Modulated Arc Therapy (VMAT) for high-risk prostate cancer with whole pelvic radiotherapy (WPRT) is complex and time-consuming.
• Investigated the use of a tuned Knowledge-Based Planning (KBP) model via a commercial system to improve radiotherapy planning.
• Focus on optimizing treatment for high-risk prostate cancer patients requiring multiple integrated dose levels.

Purpose of the Study:

• To evaluate if a well-tuned KBP model can enhance the radiotherapy planning process and improve plan quality for high-risk prostate cancer.
• To assess the impact of KBP on achieving prescribed dose levels for pelvic lymph nodes, prostate, and seminal vesicles.
• To compare the efficiency and quality of KBP-generated plans against manually created VMAT plans.

Main Methods:

• Developed an initial KBP model (RapidPlan, RP) using 69 manually planned VMAT treatments for high-risk prostate cancer.
• Used clinical plans from an RP model (July 2019-Feb 2020) to develop a second, tuned RP model.
• Validated both models on an independent cohort of 40 patients, comparing target coverage, conformity indices, and organ-at-risk doses (bladder, bowel bag, rectum).

Main Results:

• Target coverage and conformity were comparable between manual and RP-generated plans.
• The final RP model significantly reduced mean dose and generalized equivalent uniform dose (gEUD) for bladder, bowel bag, and rectum compared to manual plans (p < .05).
• Rectal dose-volume histogram (DVH) interpatient variation was reduced by 23% with the final RP model.

Conclusions:

• Knowledge-Based Planning (KBP) demonstrably improves the quality and consistency of radiotherapy treatment plans for high-risk prostate cancer.
• Tuning the KBP model using clinically delivered plans further refines outcomes, leading to superior plan quality.
• KBP offers a promising approach to streamline complex radiotherapy planning while enhancing therapeutic efficacy and patient safety.