title: Decision analysis model evaluating the cost of a temporary hydrogel rectal spacer before prostate radiation therapy to reduce the incidence of rectal complications.
abstract: We conducted a decision analysis to evaluate the cost effectiveness of a newly Food and Drug Administration approved rectal spacer gel (SpaceOAR, Augmenix) for the reduction of rectal toxicity of prostate radiation therapy (RT).
  
  
  
  A decision tree model (TreeAge Pro) was used to compare the strategy of pretherapy placement of a spacing hydrogel before RT to RT alone. The model compared costs associated with rectal complications because of rectal toxicity over a 10-year period across 3 different RT modalities. Rectal toxicity rates were estimated from studies on conformal RT dose escalation, high-dose stereotactic body radiotherapy (SBRT) and low-dose SBRT. Rectal toxicity reduction rates (baseline reduction 70%) were estimated from recently published 15 month data using a rectal spacer. Direct and indirect cost estimates for established grades of rectal toxicity were based on national and institutional costs. Reduction in short-term complications were assumed to carry forward to a reduction in long-term toxicity. One-way and two-way sensitivity analyses were performed.
  
  
  
  The overall standard management cost for conformal RT was $3,428 vs. $3,946 with rectal spacer for an incremental cost of $518 over 10 years. A 1-way sensitivity analyses showed the breakeven cost of spacer at $2,332 or a breakeven overall risk reduction of 86% at a cost of $2,850. For high-dose SBRT, spacer was immediately cost effective with a savings of $2,640 and breakeven risk reduction at 36%. However, 2-way spacer cost to risk reduction sensitivity analyses were performed.
  
  
  
  The use of a rectal spacer for conformal RT results in a marginal cost increase with a significant reduction in rectal toxicity assuming recently published 15 month rectal toxicity reduction is maintained over 10 years. For high-dose SBRT it was cost effective. Further studies would be necessary to validate the long-term benefits of rectal spacers.
authors.affiliation: Departments of Urology, The University of Texas Southwestern Medical Center, Dallas, TX.
authors.forename: Ryan C
authors.initials: RC
authors.lastname: Hutchinson
authors.affiliation: Departments of Urology, The University of Texas Southwestern Medical Center, Dallas, TX.
authors.forename: Varun
authors.initials: V
authors.lastname: Sundaram
authors.affiliation: Departments of Radiation Oncology, The University of Texas Southwestern Medical Center, Dallas, TX.
authors.forename: Michael
authors.initials: M
authors.lastname: Folkert
authors.affiliation: Departments of Urology, The University of Texas Southwestern Medical Center, Dallas, TX. Electronic address: Yair.Lotan@utsouthwestern.edu.
authors.forename: Yair
authors.initials: Y
authors.lastname: Lotan
mesh_terms: D003661:Decision Support Techniques; D003663:Decision Trees; D017048:Health Care Costs; D006801:Humans; D020100:Hydrogels / Q000191:economics / Q000627:therapeutic use*; D015994:Incidence; D008297:Male; D011471:Prostatic Neoplasms / Q000191:economics / Q000532:radiotherapy*; D011878:Radiotherapy / Q000379:methods; D012007:Rectum
chemical_list: D020100:Hydrogels
keywords: Prostate cancer; Radiation proctitis; Radiation therapy; Rectal spacer