Guideline Recommendations Purged Unnecessary Imaging in Early-Stage Breast Cancer

A study published in the journal Cancer, which found that the rate of advanced imaging at the time of breast cancer diagnosis reduced during the period between 2008 and 2015 in the state of Michigan, recommends interventions to further reduce the rates of unnecessary imaging.

The American Society of Clinical Oncology, in tandem with the American Board of Internal Medicine Foundation, released the top 5 Choosing Wisely recommendations in oncology in early 2012, one of which states:

Don’t perform PET, CT, and radionuclide bone scans in the staging of early breast cancer at low risk for metastasis.

The guidance points to the lack of evidence demonstrating a benefit of using positron emission tomography (PET), computed tomography (CT), and radionuclide bone scans in asymptomatic individuals who have been newly diagnosed with stage I or II disease, and warns about harm to patients through over-treatment, unnecessary radiation exposure, and misdiagnosis. The National Comprehensive Cancer Network provides similar advice via its Guidelines, which recommend advanced imaging techniques only in clinical stage III disease.

In the current study, clinicopathologic data and use of advanced imaging tests (PET, CT, and bone scan) were abstracted from the medical records of patients treated at 25 participating hospitals in the Michigan Breast Oncology Quality Initiative (MiBOQI). MiBOQI is a state-wide initiative that examines practice patterns in surgical, radiation, and medical oncology to improve breast cancer treatment and outcomes, and is one of several Collaborative Quality Initiatives undertaken by Blue Cross Blue Shield of Michigan.

Of the 34,078 patients diagnosed during the 7-year period between 2008 and 2015, a little over 20% (6853) had a note of at least 1 imaging modality on their records during a 90-day period after diagnosis. The number increased with more advanced disease stage: almost 25% of patients with stage IIB disease underwent at least 3 advanced imaging tests, compared with approximately 12% for patients with stage IIA disease and less than 5% for stages 0 and I. CT scans were used most commonly while PET scans were used the least.

However, the rates of testing saw significant variance across the sites. For patient with stage 0 disease, rates of testing varied from 2.5% to 43.7%, with a median of 5.5%. For stages I, IIA, and IIB, the medians were 13.0% (7.6-55.9%), 30.4% (15.266.5%), and 53.1% (27.5-84.9%), respectively. Rate of CT scans ranged from 1.3% to 43.7%, with a median of 4.6%. For stage I, IIA, and IIB, the medians were 9.5% (4.6-53.9%), 18.3% (8.3-61.5%), and 32.6% (10.6-69.9%), respectively.

Testing decreased over time for patients with stage 0-IIA disease (all P <.001) and remained stable for stage IIB disease (P = .10).

When the authors analyzed patient characteristics, they found that younger age, black race, lower socioeconomic status, higher comorbidity score, and higher clinical stage were associated with higher likelihood of advanced imaging. Additionally, ER expression, HER2 overexpression or amplification, higher tumor grade, larger tumor size, and greater number of involved lymph nodes also led to advanced imaging.

The authors conclude that while the overall rate of imaging was reduced for the study period being evaluated, the imaging rate for patients with stage II disease remained stable.

Despite this progress, the authors indicate the need for additional interventions to further reduce the rates of unnecessary testing in patients diagnosed with breast cancer.

Reference

Henry NL, Braun TM, Breslin TM, Gorski DH, Silver SM, Griggs JJ. Variation in the use of advanced imaging at the time of breast cancer diagnosis in a statewide registry [published online March 16, 2017]. Cancer. doi: 10.1002/cncr.30674.