Quality rectal hydrogel placement allows for gel-enabled dose-escalated EBRT (GEDE-EBRT) without rectal interference...

Area of Science:

• Radiation Oncology
• Medical Physics
• Urologic Oncology

Background:

• Dose-escalation in prostate cancer radiation therapy improves outcomes but is limited by rectal toxicity.
• Rectal constraints often prevent optimal radiation delivery to the prostate and surrounding structures.

Purpose of the Study:

• To investigate if rectal hydrogel (RH) placement can improve radiation dose escalation and target coverage in prostate cancer.
• To assess the dosimetric impact of RH on planning target volumes (PTVs) and rectal dose metrics.

Main Methods:

• A dosimetric study comparing treatment plans with and without RH in patients with good-quality RH.
• Plans included prostate and seminal vesicle (PSV) target volumes and peripheral zone (PZ) boosts up to 112 Gy.
• Evaluated PTV coverage (D95%) and rectal dose-volume histogram parameters with and without RH.

Main Results:

• RH placement significantly improved PTV_boost D95% (median 98.5 Gy vs 75.53 Gy) and PTV_PSV D95% (71.87 Gy vs 71.04 Gy).
• All rectal dose metrics were improved with RH compared to non-RH plans.
• RH facilitated dose escalation up to 112 Gy (EQD2 160 Gy), achieving superior target coverage and rectal sparing.

Conclusions:

• High-quality RH placement allows for dose-escalation in prostate cancer radiotherapy, improving target coverage and rectal sparing.
• This dosimetric benefit suggests RH is a valuable tool for optimizing radiation delivery in prostate cancer.
• Prospective trials are warranted to evaluate the clinical efficacy and safety, including nonrectal toxicities, of RH-guided dose-escalation.