False Positive 1, 2, & 3
What is a False Positive outcome?
A false positive (FP) is when an individual is not given a positive tissue cancer diagnosis within one year of a positive examination. After the initial positive examination, further testing is completed. In the case of an FP examination, further testing does not indicate cancer (Funaro et al., 2021).
False Positive Example from the ACR BI-RADS Atlas:
False Positive: "A woman has a screening examination and is recalled for additional imaging evaluation of a finding (Bl-RADS category 0). The diagnostic examination leads to a biopsy. The biopsy is concordantly benign, and breast cancer is not diagnosed within 1 year of the screening examination. The screening interpretation is positive (Bl-RADS category 0). The diagnostic interpretation also is positive (Bl-RADS category 4 or 5). Both the screening and diagnostic examinations are classified as false-positive (FP) because no breast cancer is diagnosed within 1 year" (Sickles et al., 2013).
What are the three types of False Positive outcomes in the mammography audit?
According to the ACR's BI-RADS atlas, the three types of FP examinations are as defined below:
- "FP1: No known tissue diagnosis of cancer within 1 year of a positive screening examination. Remember that this includes Bl-RADS category 3 assessments made at screening.
- FP2: No known tissue diagnosis of cancer within 1 year after recommendation for tissue diagnosis or surgical consultation on the basis of a positive examination (Bl-RADS category 4 or 5).
- FP3: Concordant benign tissue diagnosis (or discordant benign tissue diagnosis and no known tissue diagnosis of cancer) within 1 year after recommendation for tissue diagnosis on the basis of a positive examination (Bl-RADS category 4 or 5)" (Sickles et al., 2013).
Why is the time interval for qualifying mammogram outcomes 1 year between the initial assessment and the resulting outcome?
The BI-RADS Atlas states that the time frame for tissue diagnosis after an initial examination is one year because screening mammograms are recommended to be conducted once a year in the United States (Sickles et al., 2013).
Sources:
Sickles, EA, D'Orsi CJ, Bassett LW, et al. (2013). ACR Bl-RADS Mammography. In: ACR Bl-RADS Atlas, Breast Imaging Reporting and Data System. American College of Radiology. https://www.acr.org/Clinical-Resources/Reporting-and-Data-Systems/Bi-Rads#Mammography
Funaro, K., Ataya, D., & Niell, B. (2021). Understanding the Mammography Audit. Radiologic Clinics of North America, 59(1), 41–55. https://doi.org/10.1016/j.rcl.2020.09.009