Hi @suzie64, I has the EndoPredict test done and it advised that chemo was not recommended.
My layman's understanding of these tests is they look at information in the tumour that indicates if it is likely fast or slow growing. Chemotherapy works by targeting rapidly multiplying cells (hair, nails, many cancers). So if you have had a slow growing tumour, chances are chemo won't 'see' any stray cancer cells, as they won't have rapid activity.
I was a 'textbook perfect' candidate for the test. No node involvement, hormone positive only, very low Ki67. It is definitely not recommended for everyone and has quite specific guidelines about who the test is recommended for. It was $3,000 (no Medicare coverage) but paid for itself as it meant I didn't need more time off work once my sick leave was all used up.