@omer I looked up the CTS-5 and it is based on two trials. From the website:
"The CTS5 tool was developed for the prediction of late distant recurrence for women diagnosed with ER–positive, primary breast cancer who are recurrence–free after 5 years of endocrine therapy. Data from two large clinical trials (ATAC and BIG1–98) were used to develop the CTS5."

Is this any different from other online sites like cancermath? I am not sure.

The BCI is a genomic test done on your actual pathology specimens. I had it before it was in the guidelines. I had a second opinion oncologist and printed out the paperwork and took it to them, because they seemed more open to new things.

It might reassure you to know that the CTS-5 is pretty darn close to my recurrence risk from the BCI. The difference is that the BCI told me that extended therapy was actually of no benefit. That was independent of risk since my risk was labelled "high" (they have since changed the labelling and it now matches the CTS-5 so I am "intermediate.")