How do you approach axillary radiation in a patient with breast cancer who did not have a sentinel node biopsy?  

Choose wisely. The message from the surgery group discourages SNLN bx in 70 and above with low to intermediate grade pathology. As far as RT is concerned, AI alone, APBI, and 5 fraction whole breast are all reasonable options in those patients, and not having SNLN would not change recommendations. T...

Yes. If deemed low-risk enough to omit SLNB, which is often the case in patients older than 70, you can consider omitting specific axillary RT. In CALGB 9343 (70 or older, randomized to tam +/- tangential RT), almost 2/3 of the patients did not have axillary surgery. (I am not sure if your patient w...

Prior to the SLNB era, there'd been a wealth of surg-path studies looking at clinicopathologic factors associated with axillary nodal involvement - these predated molecular panel and breast MRI and as such are likely to overestimate involvement (sampling bias), but may be useful for risk approximati...

If you have any questions or reservations about the above recommendation, I wholeheartedly recommend a recent article on Ontario Cancer and ASCO Guidelines on management of the axilla in patients with early breast cancer, by Brackstone et al., PMID 34279999.