The PREDICT Breast v3 tool was tested in US breast cancer patients to see how well it predicts survival rates. The tool was accurate in estimating 10- and 15-year survival for most patients, but adjustments are needed for certain groups like non-Hispanic Asian and non-Hispanic Black patients with specific types of breast cancer. Overall, the tool can help doctors predict how long a patient may survive with breast cancer, but more work is needed to make sure everyone gets the same level of care.