Would you use MammaPrint in patients with triple-negative or HER2-positive breast cancer based on the results from the MINDACT trial?

The MINDACT data from the 2016 NEJM article has a lot of detail, in particular Table 1, which gives the number of subjects in each risk group sorted by clinicopathologic features. There were 638 Her2 positive subjects out of 6693 total, or 9.5%. Of these, 501 (7.5% of total) were ER positive and Her2 positive. There were 115 of these 501 "triple positive" subjects (23%) were clinically high risk but genomically low risk. About 57 subjects that were Her2 positive and ER positive received endocrin...

There are some medical oncologists using the Mammaprint assay in triple negative patients to help determine prognosis, as the original data set from Denmark was used to determine prognosis and not benefit of chemotherapy. A small T1c triple negative breast cancer with low recurrence score may not need chemotherapy.