van Wijk Y, et al. – Researchers conducted a comparative and cost–effective analysis which indicated that the virtual–implantable rectum spacer (IRS) approach in combination with a toxicity prediction model and a cost–effectiveness analyses is a promising basis for a decision support tool for the implantation of either a hydrogel spacer or a rectum balloon implant.

Methods

• Researchers evaluated the V–IRS on 16 patients: 8 with a rectal balloon implant (RBI) and 8 with a hydrogel spacer.
• They established A V–IRS applying 7 computed tomography (CT) scans of patients with a RBI.
• They applied CT scans before and after the implantation of an IRS to analyze the V–IRS,.
• IMRT plans were made based on CT scans before the IRS, after IRS and with the V–IRS, prescribing 70 Gray (Gy) to the planning target volume.
• They evaluated toxicity applying externally validated normal tissue complication probability (NTCP) models, and the Cost–effectiveness was analyzed using a published Markov model.

Results

• It was noted that the rectum volume receiving 75 Gy (V75) were improved by both the IRS and the V–IRS with on average 4.2% and 4.3% respectively.
• The data displayed that the largest NTCP reduction resulting from the IRS and the V–IRS was 4.0% and 3.9% respectively.
• It was noted that RBI was cost–effective for 1 out of 8 patients, and the hydrogel was effective for 2 out of 8 patients, and close to effective for a third patient.
• It was illustrated that the classification accuracy of the model, regarding cost–effectiveness, was 100%.