749 Background: Long-course chemoradiation (LCRT; 50.4 Gy in 28 fractions with concurrent chemotherapy) followed by surgery and adjuvant chemotherapy is the standard of care in the United States for locally advanced rectal cancer. However, many countries follow a protocol of short course radiation therapy (SCRT; 25 Gy in 5 fractions). The purpose of this study was to analyze the cost-effectiveness of SCRT versus LCRT. Methods: We developed a cost-effectiveness model simulating 10-year outcomes for 65-year-old patients treated with either SCRT or LCRT. For the base case analysis, we assumed 3D-conformal radiation treatment. We used probabilities, utilities and costs based on the literature and Medicare Fee schedules to determine the incremental cost-effectiveness ratio (ICER) of SCRT versus LCRT. We defined cost effectiveness at an ICER of $100,000/quality-adjusted life-year (QALY) or less. We assumed that SCRT would not result in tumor downstaging adequate enough to change rates of sphincter preservation, while LCRT resulted in higher rates of low anterior resection (LAR). To model preference-sensitive care, we conducted a two-way sensitivity analysis in which we simultaneously varied the utilities of the no evidence of disease states with LAR (NED-LAR) and abdominoperineal resection (APR; NED-APR). To model current practice, we repeated the analysis assuming 3D-conformal treatment for LCRT but intensity modulated radiation therapy (IMRT) for SCRT. Results: With an ICER of $351,731/QALY, SCRT was cost-effective as compared to LCRT. SCRT remained the cost-effective strategy with 3D-conformal treatment for LCRT but IMRT for SCRT (ICER of $314,022/QALY). On one-way sensitivity analysis, LCRT became the cost-effective approach when the utility of NED-APR was below 0.61. Two-way sensitivity analysis revealed that the cost-effective approach for a given patient depended on the utilities for the NED-LAR and NED-APR states. Conclusions: SCRT was the cost-effective strategy as compared to LCRT. However, the cost effectiveness of SCRT versus LCRT was sensitive to the utilities of NED-LAR and NED-APR, highlighting the importance of patient preference-sensitive care.
Cost-Effectiveness of Short Course Radiation Therapy Versus Long-Course Chemoradiation for Locally Advanced Rectal Adenocarcinoma
