How are you planning to use Mammaprint for the management of locally advanced ER+ breast cancer at clinical high risk of recurrence based on size and up to 3 lymph nodes?

This is an interesting question. I am going to use Mammaprint in the adjuvant setting for patients with high risk of recurrence for tumors of any size and for 0-3 LN positive. These were the criteria used in the MINDACT study, and the 5 year distant DFS in these patients was 95% with endocrine therapy alone when they had a high risk clinical picture but a low risk Mammaprint in this prospective trial providing level 1 evidence of benefit. There is talk of a potential 1.5% additional benefit to chemotherapy in these women, but this was not statistically significant in MINDACT, and the 1.5% benefit is to me generally not clinically significant (ie 67 women have to be treated with chemotherapy to prevent one distant recurrence). I also will co...

I agree with @Dr. First Last in principle, although I am still cautious in younger women, and more disease in the lymph node. I have not used it in HER2+ disease either, but I agree that there is a small proportion of ER+HER2+ patients where chemotherapy may not as beneficial. I argue that the HER2 pathway is still relevant in these patients and HER2-targeted therapy needs to be administered, and often this is standard with chemotherapy.