Would you recommend adjuvant chemotherapy therapy to a premenopausal patient with ER+ lobular breast cancer who had a partial response to neoadjuvant endocrine therapy?  

One approach is if you have enough tissue from the diagnostic core biopsy to run an Oncotype then base your decision on adjuvant chemo from that. This is assuming you are confident she is a N1 case (no treatment effects noted in other nodes). There is an ASCO 2018 abstract from Mayo (Talal Hilal et ...

Results from TailoRx, MINDACT and other trials demonstrate that tumor biology is more important than most other prognostic factors in terms of estimating risk of distant recurrence and benefit of various adjuvant therapies, though we shouldn't toss out more traditional factors, such a...