Impact of Rectal Gas on Carbon Ion Therapy for Prostate Cancer
Author Information
Author(s): Ishizawa Miyu, Miyasaka Yuya, Souda Hikaru, Ono Takashi, Chai Hongbo, Sato Hiraku, Iwai Takeo
Primary Institution: Yamagata University
Hypothesis
This study aims to determine the dosimetric influence of rectal gas in carbon ion radiation therapy for prostate cancer.
Conclusion
Rectal gas removal may not be necessary up to 4 fractions in carbon ion therapy for prostate cancer.
Supporting Evidence
- Rectal gas may affect dose distribution for prostate cancer in carbon ion therapy.
- Removing bulky rectal gas was previously considered mandatory at the institution.
- Even with rectal gas present for up to 4 of 12 fractions, dose change remained small.
- Indicators related to dose changes were highly correlated with the extent of rectal gas.
Takeaway
Doctors found that having gas in the rectum during prostate cancer treatment doesn't change the dose of radiation much, so they might not need to remove it for the first few treatments.
Methodology
The study analyzed 18 prostate cancer cases with bulky rectal gas, recalculating dose distributions on CT scans with and without gas.
Potential Biases
The results may be influenced by the assumption that rectal gas conditions are similar across evaluations.
Limitations
The study only analyzed 1 gasCT per patient, which may not represent variations in rectal gas volume and location.
Participant Demographics
All participants were medium-risk prostate cancer patients undergoing carbon ion radiation therapy.
Statistical Information
P-Value
p=0.037 for V95% rectum at 4 fx
Statistical Significance
p<0.05
Digital Object Identifier (DOI)
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