Cost effectiveness of new breast cancer radiotherapy technologies in diverse populations

Heather Taffet Gold, Mary Katherine Hayes

Accelerated partial breast radiotherapy (RT) strategies (3-D conformal external-beam RT (3-D CRT) and brachytherapy with balloon catheter) reduce time and transportation burdens of whole breast RT for breast cancer. Long-term clinical trial evidence is unavailable for accelerated modalities, but uncertainty might be acceptable for patients likely to receive suboptimal whole breast RT. The objective of this study is to assess the cost effectiveness of accelerated partial breast RT compared to on-time and delayed whole breast RT. The design used in this study is decision analytic Markov model. The data sources are published literature; and national/federal sources. The target population of this study is a hypothetical cohort of 60 years old women previously treated with breast-conserving surgery for node-negative, estrogen receptor-positive breast cancer with tumors <1 cm. The time horizon is 15 years, and the perspective is societal. The interventions are whole breast RT, 3-D CRT, and brachytherapy breast irradiation. The outcome measures are costs (2008 US$), quality-adjusted life years (QALYs), and incremental cost-effectiveness ratios. The base-case results were: 3-D CRT was the preferred strategy, costing on average $10,800 and yielding 11.21 QALYs. On-time whole breast RT costs $368,000/QALY compared to 3-D CRT, above the $100,000/QALY WTP threshold. 3-D CRT was also preferred over delayed whole breast RT. Brachytherapy was never preferred. Sensitivity analysis indicated that the results were sensitive to the rate of recurrence outside the initial tumor quadrant ("elsewhere failure") in one-way analysis. Probabilistic sensitivity analysis indicated that results were sensitive to parameter uncertainty, and that the elsewhere-failure rate and treatment preferences may drive results. The limitation of this study is that efficacy estimates are derived from studies that may not fully represent the population modeled. As a conclusion, 3-D CRT was preferred to whole breast RT and for women likely to delay RT, indicating that 3-D CRT could be targeted more efficiently before randomized trial evidence.