Examining the cost-effectiveness of radiation therapy among older women with favorable-risk breast cancer.

Abstract

Little is known about the cost-effectiveness of external beam radiation therapy (EBRT) or newer radiation therapy (RT) modalities such as intensity modulated radiation (IMRT) or brachytherapy among older women with favorable-risk breast cancer. Using a Markov model, we estimated the cost-effectiveness of no RT, EBRT, and IMRT over 10 years. We estimated the incremental cost-effectiveness ratio (ICER) of IMRT compared with EBRT under different scenarios to determine the necessary improvement in effectiveness for newer modalities to be cost-effective. We estimated model inputs using women in the Surveillance, Epidemiology, and End Results-Medicare database fulfilling the Cancer and Leukemia Group B C9343 trial criteria. The incremental cost of EBRT compared with no RT was $9500 with an ICER of $44600 per quality-adjusted life year (QALY) gained. The ICERs increased with age, ranging from $38300 (age 70-74 years) to $55800 (age 80 to 94 years) per QALY. The ICERs increased to more than $63800 per QALY for women aged 70 to 74 years with an expected 10-year survival of 25%. Reduction in local recurrence by IMRT compared with EBRT did not have a substantial impact on the ICER of IMRT. IMRT would have to increase the utility of baseline state by 20% to be cost-effective (<$100000 per QALY). EBRT is cost-effective for older women with favorable risk breast cancer, but substantially less cost-effective for women with shorter expected survival. Newer RT modalities would have to be substantially more effective than existing therapies in improving quality of life to be cost-effective.