Zero negative lymph nodes does not preclude having the OncotypeDX genomics testing. I had a clean sentinel lymph node biopsy and had the test. A friend with a Stage 1 tumor and clean (negative for cancer cells) sentinel lymph node biopsy had the test as well.

According to a scientist at Exact Sciences (provider of the OncotypeDX), approximately 15% of the OncotypeDX results yield a 'risk of recurrence within 9 years' of 3% or lower (if taking anti-hormone therapy). The overwhelming majority of those low-risk clients also had clean lymph(s) but not all. The person I spoke with didn't have the exact breakdown but had an impression that maybe as high as 75-80% of the low risk results corresponded to clients who also had clean sentinel (or other) lymph node biopsies.