Hydrogel Spacer Insertion Prior to Stereotactic Body Radiation Therapy to the Prostate: A Comparative Study.

Area of Science:

• Oncology
• Radiation Oncology
• Medical Physics

Background:

• Stereotactic body radiation therapy (SBRT) for prostate cancer can cause rectal and urinary toxicity.
• Hydrogel spacers are used to reduce rectal radiation dose during SBRT.
• Clinical data on the benefit of hydrogel spacers in SBRT are limited.

Purpose of the Study:

• To investigate the clinical benefit of hydrogel spacer insertion in patients undergoing SBRT for prostate cancer.
• To evaluate the impact of hydrogel spacers on rectal and urinary toxicity.
• To assess procedure-related complications.

Main Methods:

• Retrospective study of 308 prostate cancer patients undergoing SBRT (2013-2018).
• Comparison of rectal and urinary toxicity (National Cancer Institute Common Terminology Criteria for Adverse Events v4) between patients with and without hydrogel spacers.
• Subgroup analysis for patients receiving 37.5 or 40 Gy in 5 fractions.
• Evaluation of procedure-related complications.

Main Results:

• No statistically significant difference in grade 2 or higher rectal toxicity (13.9% with spacer vs. 12% without).
• No statistically significant difference in grade 2 urinary toxicity (26% with spacer vs. 18.6% without).
• Severe procedure-related complications occurred in 2.2% of cases with spacers.

Conclusions:

• Hydrogel spacer insertion did not demonstrate a significant reduction in rectal or urinary toxicity for prostate cancer SBRT.
• The clinical benefit of hydrogel spacers in this context is questionable.
• Further studies are recommended for selective use of hydrogel spacers due to potential complications.