If a breast cancer patient undergoes neo-adjuvant chemotherapy, how will she ever know her true nodal status?

Sentinel LN Biopsy: It is somewhat controversial when to perform sentinel lymph node (ln) biopsy in this setting: some advocate performing this prior to chemo, so as to determine an accurate stage; others believe that the status of the ln after chemo is most pertinent. In my practice, i will perform a needle-biopsy of any abnormal ln prior to chemo. If none are evident, i wait until after chemo.

She won't: I used to always ask surgeons to do a sentinel node biopsy before neoadjuvant chemotherapy for that very reason. However, newer data show the lymph node status after chemotherapy may be more important. Newer data also show that women don't always need a full axillary dissection with a few positive nodes, so i'm ok with either approach if the lymph nodes aren't enlarged to start.

"true" nodal status?: With neoadj therapy, prognostic infor of staging after therapy is likely the more telling. Studies show slnbx after chemo still accurately predicts axillary nodal status. With current chemo, a 20-25% PCR is not unexpected and would include clearing previously pos nodes (found clinically or on prechemo ax u/s & fna). Delaying the slnbx can thus spare these patients additional axillary surgery.