True Positive
What is a True Positive outcome?
A true positive (TP) outcome is when an individual is given a positive tissue diagnosis for cancer within one year of a positive examination. It is worth noting that positive screening and diagnostic mammogram results are defined differently (positive screening: BI-RADS 0 and 3; positive diagnostic: BI-RADS 4 and 5) (Funaro et al., 2021).
Example of True Positive from the ACR BI-RADS Atlas:
True Positive: “A woman has a screening examination and is recalled for additional imaging evaluation of a finding (Bl-RADS category 0). The diagnostic breast imaging examination is read as suspicious (Bl-RADS category 4) with a recommendation for tissue diagnosis, a biopsy is performed, and the tissue diagnosis is malignant. Both the screening and diagnostic interpretations are positive, and because cancer is diagnosed within 1 year, both examinations are classified as true positive (TP)” (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 reason the time frame for tissue diagnosis after an initial examination is one year is 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