Purpose
To assess whether simethicone reduces the rectal volume (RV) and volume of gas in the rectum (GV) in men undergoing prostate cancer radiation therapy, in order to increase treatment accuracy and decrease toxicity by minimising inter-fraction target volume motion.
Methods and materials
This trial was a prospective, single centre, non-blinded, randomised controlled trial. It included prostate cancer patients being treated with external beam radiation therapy radically to an intact prostate, as well as salvage or adjuvant radiation therapy to the prostate bed, with or without the inclusion of the pelvic lymph nodes. 30 patients were randomised 1:1 to the simethicone or no intervention arm. The simethicone arm had a dose of 100mg three times per day for three days prior to their planning scan, restarted simethicone three...
Results
264 CBCTs were analysed
RV and GV were not significantly different at each time point (p>0.05)
There was an average reduction in RV and GV of 10% and 21% respectively in the simethicone group when compared to the control group, but not reaching statistical significance.
Standard deviations calculated for each patient over the 10 time points were not significantly different between the two groups (p>0.05)
Patients in the simethicone group had a decrease in the variability of RV at timepoints 6-10 (weeks 4 to 8)...
Conclusion
Simethicone did not increase toxicity from radiation therapy.
Simethicone significantly lowered the variability of RV in the later stages of the treatment period, suggesting that if taken at least 2 weeks prior to radiation therapy, it may be beneficial throughout treatment.
These results support further investigation into the efficacy of simethicone in reducing RV and GV variability, with earlier commencement of simethicone and a larger number of patients.
References
Halkett GKB, Wigley CA, Aoun SM, Portaluri M, Tramacere F, Livi L, et al. International validation of the EORTC QLQ-PRT20 module for assessment of quality of life symptoms relating to radiation proctitis: a phase IV study. Radiat Oncol. 2018;13(1):162.
Fayers PM AN, Bjordal K, Groenvold M, Curran D, Bottomley A, on behalf of the EORTC Quality of Life Group. The EORTC QLQ-C30 Scoring Manual (3rd Edition): European Organisation for Research and Treatment of Cancer, Brussels 2001.; 2001 [3rd:[Scoring manual for EORTC QLQ-C30 ]. Available from:...