Distribution analysis of hydrogel spacer and evaluation of rectal dose reduction in Japanese prostate cancer patients undergoing stereotactic body radiation therapy

Hiroaki Kobayashi, Takahisa Eriguchi, Tomoki Tanaka, Takeru Ogata, Masaru Ishida, Yosuke Nakajima, Atsuhiro Kumabe, Michio Kosugi

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

Background: To report on our primary experience with the placement of a hydrogel spacer following stereotactic body radiation therapy (SBRT) in low- and intermediate-risk prostate cancer patients and assess its impact on dosimetry as well as acute toxicity. Methods: A total of 70 patients treated with SBRT (total dose of 36.25 Gy) in 5 fractions were included. Hydrogel spacers were inserted in 53 patients along with gold fiducial markers. For dosimetry, we trisected the rectum on the sagittal image of magnetic resonance imaging and defined it as the upper rectum (UR), middle rectum (MR), and lower rectum (LR). We compared the dose to each part of the rectum with and without hydrogel spacer using dose volume histograms. Genitourinary (GU) and gastrointestinal (GI) toxicity assessments were conducted until 6 months of follow-up visits. Results: The median volume of the hydrogel spacer was 12.3 mL. Overall, the hydrogel spacer could significantly reduce the rectal dose in the middle-to-high-dose region (V20–V35). The rectum doses at the UR and MR were significantly lower in the spacer group in the middle to high dose region (V20–V35); the dose at the LR was significantly lower in the spacer group in the high-dose region (V30–V35). There was no grade ≥ 3 toxicity observed, but grade 2 toxicity of GU and GI occurred in 17.1% and 1.4% of the patients, respectively. Conclusion: Hydrogel spacers could contribute to rectal dose reduction, especially in high dose regions, by creating a prostate–rectum distance.

Original languageEnglish
Pages (from-to)736-743
Number of pages8
JournalInternational Journal of Clinical Oncology
Volume26
Issue number4
DOIs
Publication statusPublished - 2021 Apr
Externally publishedYes

Keywords

  • Genitourinary and gastrointestinal toxicities
  • Hydrogel spacer
  • Rectal dose reduction
  • Stereotactic body radiation therapy

ASJC Scopus subject areas

  • Surgery
  • Hematology
  • Oncology

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