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Cost Effectiveness Analysis of Stereotactic Body Radiation Therapy (SBRT) versus Intensity Modulated Radiation Therapy (IMRT) for Low or Intermediate Risk Prostate Cancer: A Markov Model Decision Analysis
I. J. Radiation Oncology d Biology d Physics
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were significantly less likely to feel comfortable reporting an error (85% vs. 95% for those never reprimanded, p = 0.037). d) The perceived major obstacles to error reporting included poor communication (19%) and the hierarchical structure of their clinic (16%). Respondents working in private practice were more likely than those in academics to report good personal communication with physicists (97% vs. 87%, p = 0.038) and administrators (80% vs. 67%, p = 0.046). Conclusions: The majority of dosimetrists feel communication in their clinics is good and that there are systems in place to report errors. A sizable minority of dosimetrists reported experience with reprimand for error reporting that significantly reduced their comfort level with reporting errors. Improving communication systems and reducing the hierarchical nature of clinics, especially in the academic setting, may improve error reporting in radiation oncology. Author Disclosure: J.A. Church: None. J.A. Holmes: None. R.D. Adams: None. L.H. Hendrix: None. M. Jackson: None. S.X. Chang: None. K.D. Burkhardt: None. L.B. Marks: None. R.C. Chen: None.
2729
Cost Effectiveness Analysis of Stereotactic Body Radiation Therapy (SBRT) versus Intensity Modulated Radiation Therapy (IMRT) for Low or Intermediate Risk Prostate Cancer: A Markov Model Decision Analysis
J. C. Hodges1, T. Boike1, Y. Lotan2, R. Benton1, D. A. Pistenmaa1, H. Choy1, R. Timmerman1 1 Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX, 2Department of Urology, University of Texas Southwestern Medical Center, Dallas, TX
Purpose/Objective(s): In several recent phase I and II clinical trials, stereotactic body radiation therapy (SBRT) for low or intermediate risk prostate cancer has shown high levels of biochemical control and equally low toxicity burden compared to intensity-modulated radiation therapy (IMRT). The purpose of this study is to compare the cost effectiveness of two external beam radiation therapy techniques of SBRT and IMRT for low or intermediate risk prostate cancer. Materials/Methods: A Markov decision tree with probabilistic sensitivity analysis modeling the various disease states of a 70 year old patient with low or intermediate risk prostate cancer was developed. Model assumptions were based on a recent random effects meta-analysis; extensive literature review of costs, utilities, transition rates; and our institutional cost data for evaluation, treatment planning and delivery. Two different prostate radiation techniques were considered: 1) SBRT 35 - 50 Gy in 5 fractions; 2) IMRT 79.2 Gy in 44 fractions. Results: The costs for SBRT were analyzed based on delivery with a non robotic linear accelerator consistent with our institution’s SBRT treatment techniques. Given a recent report of 5 year outcomes data with SBRT, the base case assumed equal efficacy and quality of life. At ten years follow up, the Monte Carlo simulation revealed that the mean costs and quality adjusted life years (QALYs) for SBRT and IMRT were $19,155 (7.9) and $32,468 (7.9), respectively. In addition, in order to investigate the effect of relaxing the base case assumptions, sensitivity analysis was performed by varying the efficacy and quality of life of patients treated with SBRT. This sensitivity analysis revealed that a decrease in quality of life of 3.5% or a decrease in efficacy of 8% for patients treated with SBRT would no longer render an incremental cost-effectiveness ratio of\$50,000 per QALY when comparing SBRT to IMRT. Conclusions: Compared to IMRT, SBRT for low or intermediate prostate cancer has great potential cost savings for our healthcare system and may improve access to radiation, increase patient convenience, and boost quality of life for patients. Our model also suggests that the incremental cost effectiveness ratio of SBRT over IMRT is highly sensitive to quality of life outcomes which should be adequately and comparably measured in current and future prostate SBRT studies. Author Disclosure: J.C. Hodges: None. T. Boike: None. Y. Lotan: None. R. Benton: None. D.A. Pistenmaa: None. H. Choy: None. R. Timmerman: B. Research Grant; Department of Defense.
2730
Vaginal Dilator Use after Pelvic and Intravaginal Radiotherapy: Preliminary Analysis of Compliance and Effectiveness
E. Law, N. Kline, B. Thom, K. Alektiar, E. Riedel, K. Kaufman, G. Cohen, J. Kelvin, D. Paolilli, K. Goodman Memorial Sloan-Kettering Cancer Center, New York, NY Purpose/Objective(s): Vaginal stenosis is a known late effect of pelvic radiotherapy (RT) that can significantly impact long-term quality of life. This prospective study evaluated compliance with and effectiveness of vaginal dilator use after pelvic and/or intravaginal (IV) RT. Materials/Methods: Women with colorectal and gynecologic cancers treated with pelvic and/or IV RT were enrolled and dilator size was assessed before start of RT and at 1, 3, 6 and 12 months post-RT. Patients (pts) were instructed to follow vaginal dilation recommendations of 3 times per week post-RT and recorded vaginal dilator size (1 - 4) and vaginal symptoms with each use in monthly diaries for 12 months. Clinicians used CTCAE v.3 to grade vaginal stenosis. Vaginal pain and tightness were measured on 0-10 scale, with 0 being no pain/tightness. Results: To date, 106 pts with rectal (n = 28), anal (n = 30), endometrial (n = 45), cervical (n = 2) and ovarian (n = 1) cancers have been enrolled. Average age was 57.5 years. Average total vaginal dose for pelvic RT was 3466 cGy. IVRT prescription at 0.5 cm from the surface of the vaginal cylinder was 6Gy x 3 fractions and 7Gy x 3 fractions for 2.6 cm and 3 cm cylinders, respectively. The treatment length ranged from 4 - 7 cm. Twenty-three pts were removed from study due primarily to withdrawal of consent or progression of disease. Thirty-four pts have completed 12 months of follow-up, among whom, compliance with dilator use at 3 times per week was 35% at 10 months after RT, but only 12% at 11 months and 5% at 12 months. Reasons for non-compliance included indifference about dilator use and hospitalization. One month after RT, 18 of 34 pts had a decrease in dilator size, from a mean of 3.7 at baseline to a mean of 2.1, 11 maintained their baseline dilator size, while five were able to use the next larger size. By 6 and 12 months after RT, 61% and 72% of the 18 pts who had decreased dilator size from one month post-RT were able to return to their baseline dilator size, respectively. Overall, 79% of the 34 pts were able to return to using baseline dilator size. Vaginal pain during dilation peaked at 1 month post-RT (mean = 1.76) and decreased after 6 months (mean = 1.0) but increased
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Volume 81, Number 2, Supplement, 2011
were significantly less likely to feel comfortable reporting an error (85% vs. 95% for those never reprimanded, p = 0.037). d) The perceived major obstacles to error reporting included poor communication (19%) and the hierarchical structure of their clinic (16%). Respondents working in private practice were more likely than those in academics to report good personal communication with physicists (97% vs. 87%, p = 0.038) and administrators (80% vs. 67%, p = 0.046). Conclusions: The majority of dosimetrists feel communication in their clinics is good and that there are systems in place to report errors. A sizable minority of dosimetrists reported experience with reprimand for error reporting that significantly reduced their comfort level with reporting errors. Improving communication systems and reducing the hierarchical nature of clinics, especially in the academic setting, may improve error reporting in radiation oncology. Author Disclosure: J.A. Church: None. J.A. Holmes: None. R.D. Adams: None. L.H. Hendrix: None. M. Jackson: None. S.X. Chang: None. K.D. Burkhardt: None. L.B. Marks: None. R.C. Chen: None.
2729
Cost Effectiveness Analysis of Stereotactic Body Radiation Therapy (SBRT) versus Intensity Modulated Radiation Therapy (IMRT) for Low or Intermediate Risk Prostate Cancer: A Markov Model Decision Analysis
J. C. Hodges1, T. Boike1, Y. Lotan2, R. Benton1, D. A. Pistenmaa1, H. Choy1, R. Timmerman1 1 Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX, 2Department of Urology, University of Texas Southwestern Medical Center, Dallas, TX
Purpose/Objective(s): In several recent phase I and II clinical trials, stereotactic body radiation therapy (SBRT) for low or intermediate risk prostate cancer has shown high levels of biochemical control and equally low toxicity burden compared to intensity-modulated radiation therapy (IMRT). The purpose of this study is to compare the cost effectiveness of two external beam radiation therapy techniques of SBRT and IMRT for low or intermediate risk prostate cancer. Materials/Methods: A Markov decision tree with probabilistic sensitivity analysis modeling the various disease states of a 70 year old patient with low or intermediate risk prostate cancer was developed. Model assumptions were based on a recent random effects meta-analysis; extensive literature review of costs, utilities, transition rates; and our institutional cost data for evaluation, treatment planning and delivery. Two different prostate radiation techniques were considered: 1) SBRT 35 - 50 Gy in 5 fractions; 2) IMRT 79.2 Gy in 44 fractions. Results: The costs for SBRT were analyzed based on delivery with a non robotic linear accelerator consistent with our institution’s SBRT treatment techniques. Given a recent report of 5 year outcomes data with SBRT, the base case assumed equal efficacy and quality of life. At ten years follow up, the Monte Carlo simulation revealed that the mean costs and quality adjusted life years (QALYs) for SBRT and IMRT were $19,155 (7.9) and $32,468 (7.9), respectively. In addition, in order to investigate the effect of relaxing the base case assumptions, sensitivity analysis was performed by varying the efficacy and quality of life of patients treated with SBRT. This sensitivity analysis revealed that a decrease in quality of life of 3.5% or a decrease in efficacy of 8% for patients treated with SBRT would no longer render an incremental cost-effectiveness ratio of\$50,000 per QALY when comparing SBRT to IMRT. Conclusions: Compared to IMRT, SBRT for low or intermediate prostate cancer has great potential cost savings for our healthcare system and may improve access to radiation, increase patient convenience, and boost quality of life for patients. Our model also suggests that the incremental cost effectiveness ratio of SBRT over IMRT is highly sensitive to quality of life outcomes which should be adequately and comparably measured in current and future prostate SBRT studies. Author Disclosure: J.C. Hodges: None. T. Boike: None. Y. Lotan: None. R. Benton: None. D.A. Pistenmaa: None. H. Choy: None. R. Timmerman: B. Research Grant; Department of Defense.
2730
Vaginal Dilator Use after Pelvic and Intravaginal Radiotherapy: Preliminary Analysis of Compliance and Effectiveness
E. Law, N. Kline, B. Thom, K. Alektiar, E. Riedel, K. Kaufman, G. Cohen, J. Kelvin, D. Paolilli, K. Goodman Memorial Sloan-Kettering Cancer Center, New York, NY Purpose/Objective(s): Vaginal stenosis is a known late effect of pelvic radiotherapy (RT) that can significantly impact long-term quality of life. This prospective study evaluated compliance with and effectiveness of vaginal dilator use after pelvic and/or intravaginal (IV) RT. Materials/Methods: Women with colorectal and gynecologic cancers treated with pelvic and/or IV RT were enrolled and dilator size was assessed before start of RT and at 1, 3, 6 and 12 months post-RT. Patients (pts) were instructed to follow vaginal dilation recommendations of 3 times per week post-RT and recorded vaginal dilator size (1 - 4) and vaginal symptoms with each use in monthly diaries for 12 months. Clinicians used CTCAE v.3 to grade vaginal stenosis. Vaginal pain and tightness were measured on 0-10 scale, with 0 being no pain/tightness. Results: To date, 106 pts with rectal (n = 28), anal (n = 30), endometrial (n = 45), cervical (n = 2) and ovarian (n = 1) cancers have been enrolled. Average age was 57.5 years. Average total vaginal dose for pelvic RT was 3466 cGy. IVRT prescription at 0.5 cm from the surface of the vaginal cylinder was 6Gy x 3 fractions and 7Gy x 3 fractions for 2.6 cm and 3 cm cylinders, respectively. The treatment length ranged from 4 - 7 cm. Twenty-three pts were removed from study due primarily to withdrawal of consent or progression of disease. Thirty-four pts have completed 12 months of follow-up, among whom, compliance with dilator use at 3 times per week was 35% at 10 months after RT, but only 12% at 11 months and 5% at 12 months. Reasons for non-compliance included indifference about dilator use and hospitalization. One month after RT, 18 of 34 pts had a decrease in dilator size, from a mean of 3.7 at baseline to a mean of 2.1, 11 maintained their baseline dilator size, while five were able to use the next larger size. By 6 and 12 months after RT, 61% and 72% of the 18 pts who had decreased dilator size from one month post-RT were able to return to their baseline dilator size, respectively. Overall, 79% of the 34 pts were able to return to using baseline dilator size. Vaginal pain during dilation peaked at 1 month post-RT (mean = 1.76) and decreased after 6 months (mean = 1.0) but increased