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Prostate Cancer Treatment with Pencil Beam Proton Therapy Using Rectal Spacers sans Endorectal Balloons - PubMed

Prostate Cancer Treatment with Pencil Beam Proton Therapy Using Rectal Spacers sans Endorectal Balloons - PubMed

Source : https://pubmed.ncbi.nlm.nih.gov/35774493/

doi: 10.14338/IJPT-21-00039. 1 Department of Radiation Medicine, Georgetown University Hospital, Washington, DC, USA. 2 Department of Urology, Georgetown University Hospital, Washington, DC, USA. 3 Department of Radiology, Georgetown University Hospital, Washington, DC, USA. 4 Department of Radiation Oncology, Perlmutter Cancer Center at New York University Langone Hospital - Long Island, New York, NY, USA.


Conclusion: Early clinical outcomes of patients treated with PBS–PBT using Monte Carlo–based planning, fiducial placement, and rectal spacers sans endorectal balloons demonstrate minimal treatment-related toxicity with good oncologic outcomes. Rectal spacer stabilization without the use of endorectal balloons is feasible for the use of PBS–PBT.

  • July 20, 2022
    Key Points
    • Source: International Journal of Particle Therapy
    • Relevance: “Early clinical outcomes of patients treated with PBS–PBT using Monte Carlo–based planning, fiducial placement, and rectal spacers sans endorectal balloons demonstrate minimal treatment-related toxicity with good oncologic outcomes. Rectal spacer stabilization without the use of endorectal balloons is feasible for the use of PBS–PBT.”
    • In the current retrospective study, U.S. researchers evaluated the early clinical outcomes in patients receiving treatment for localized prostate cancer via pencil beam scanning-proton beam radiotherapy (PBS-PBT). These patients had hydrogel rectal spacing and fiducial tracking but not endorectal balloons and were followed for 18 months.
    • “Our early experience demonstrates excellent dosimetry using active scanning proton therapy with Monte Carlo planning resulting in low dose–volume parameters for the bladder and, particularly, the rectum,” the authors wrote.
    • There were few occurrences of acute GI toxicity, and no patient complaining of a grade 2+ acute GI toxicity or grade 3+ GU toxicity.
    • “Hydrogel spacers are polyethylene glycol-based gels, which create a geometrical expansion of the potential space between the posterior aspect of the prostate and the anterior aspect of the rectum,” the authors wrote. “As a result, considerable separation between the prostate and rectum is achieved resulting in rectal dosimetric improvements across nearly all dose–volume parameters. These dosimetric improvements have translated into particularly low rates of clinical GI toxicity and excellent patient-reported quality of life for intensity-modulated radiation treatments.”
    • Proton therapy requires anatomical reproducibility, which is proffered by hydrogel spacers. This reproducibility is akin to the daily use of endorectal balloons without the discomfort/inconvenience, per the authors.
    • Limitations of the current study include its nonrandomized and retrospective design, as well as its short duration, which allowed for only the evaluation of acute toxicities or acute oncological outcomes.