OBJECTIVES: The American Society of Clinical Oncology’s Choosing Wisely (CW) initiative recommends against the use of staging imaging procedures in patients with early-stage breast cancer who are at the low risk of metastasis. The impact of CW on staging imaging in older patients with early-stage breast cancer by their cancer stage was examined.

METHODS: A retrospective observational cohort study using the Surveillance, Epidemiology, End Results-Medicare linked database was conducted. Women age >66 years diagnosed with stage 0-II incident breast cancer during 2007-2015 were included (N=84,606). The proportion of patients with at least one claim of Positron Emission Tomography (PET), Computerized Tomography (CT), or radionuclide bone scans in three months prior to and three months following cancer diagnosis, were identified for pre- and post-CW periods. Separate interrupted time-series (ITS) analyses and segmented regressions were conducted to evaluate if CW reduced the rate of staging imaging use by cancer stage.

RESULTS: In unadjusted analyses, staging imaging use declined during the post-CW period compared to the pre-CW period for each cancer stage (16.2% to 13.5% for stage 0, 29.3% to 22.3% for stage I, 44.0% to 37.7% for stage IIa, 59% to 56.1% for stage IIb). ITS analyses showed that there was a non-significant 0.003% point per quarter increase in the rate of staging imaging use resulting from CW for women with stage 0 breast cancer. However, for women with stage I cancer, there was a minor significant 0.07% per quarter decrease in the rate of staging imaging use resulting from CW. For women with stage IIa and IIb cancer, there was a significant 0.22% point and 0.28% point per quarter increase, respectively, in the rate of staging imaging resulting from CW.

CONCLUSIONS: Our findings underscore the continuous challenge of reducing unnecessary medical procedures in women with breast cancer, especially those with relatively higher stage disease.