What is your approach to women with breast cancer who opts for a staged approach with up-front lumpectomy and SLN biopsy (pN-) when there are indications for adjuvant radiation therapy but she plans for a later mastectomy (=>6 months)?

I would not offer RT if planned for mastectomy in 6 months, as based on phenotype, median time for recurrence is 2 to 5 years, and RT can also negatively impact the cosmetic outcome with reconstruction.

That is not a common approach I have seen, and I would question the rationale of putting a patient through two surgeries when one can be done and forgo RT. If pN0, it would depend on what significant delay is, and I would extensively counsel the patient on recurrence risk should they end up forgoing...