PD06-08: Projecting the Impact of Adopting Trial Results
Authors: Esserman LJ , Mohan AJ , Park C , Berry DA , Ozanne E , Alvarado MD 
Published: June 2012

Background: There is often a substantial delay between the presentation of clinical trial results and change in practice. Reasons for slow adoption include the disruption of practice routines, doubt about the validity of results, financial disincentive, and resistance to change. We propose a decision-making process to inform adoption that considers three factors: likelihood the trial's conclusions will not change with longer follow up, and consequences of early and late adoption. We apply this framework to the published 4-year results of the international TARGIT-A trial, which compares intraoperative radiation therapy (IORT) to external beam radiation therapy (EBRT).

Methods: To find whether the trial results will remain robust, we reviewed the TARGIT-A trial's annual hazards for local recurrence (LR). We then reviewed 5–10 year LR rates from recent clinical trials with similar patient populations undergoing RT, no RT or partial breast RT. To assess the impact of an early change in practice, a Markov model was used to evaluate life expectancy, quality adjusted life years (QALYs), and cost. Sensitivity analysis estimated the impact of varying the LR rate 1–20x the TARGIT-A 4 year results. To estimate the impact of late adoption, we generated the expected number of N0, grades 1 & 2, ductal cancers in postmenopausal women (&gt;50 yrs) from SEER and US Census Bureau data. Using Medicare rates, costs of EBRT vs. IORT were compared and potential savings to the health care system calculated.

Results: The TARGIT-A peak hazard for LR for IORT and EBRT occurred at 3 years. In the START and ATAC trials, the peak local recurrence Kaplan Meier estimates are between 2 and 3 years. In other trials (ATAC, and in the 2005 RT Lancet overview) there is no second peak of recurrence, making it unlikely that longer follow up will change the conclusion of the TARGIT-A results. The LRR in similar trials have dropped steadily over time for post menopausal, stage I patients with or without RT. Impact of early adoption: If treatment were adopted early, the impact on life expectancy and QALYs would be minimal unless IORT LR rate exceeds 20% over a 10 year period of time. Impact of late adoption: In the US, 45% of new breast cancer cases fit the described population. EBRT costs $6,400 more than IORT per patient on average. If adoption were delayed 5 years to allow the trial results to mature, 70,136 patients per year are expected to receive EBRT resulting in a societal burden of &gt;$2.2 billion barring the capital investment required for new technology. This also assumes that patients have equal utility for a single dose of IORT as they do for 3–6 weeks of postoperative radiation therapy. If IORT utility is higher than that of EBRT, then the IORT strategy is both more effective and less costly.

Conclusion: The process of modeling the impact of both early and late adoption when considering the stability of trial results can serve as a tool to evaluate whether to change practice. This analysis was tested on the results of the TARGIT-A trial, and demonstrated that prompt adoption of the IORT intervention would cause minimal harm, provide an improved quality of life, and offer significant societal savings.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr PD06-08.