NSABP B-32
In clinically node-negative breast cancer, can sentinel lymph-node surgery replace routine axillary lymph-node dissection without compromising survival or regional control?
SLN surgery alone versus SLN surgery plus ALND among patients with pathologically negative SLNs.
There were 8 versus 14 regional-node recurrences as first events (P=.22).
OS HR 1.20 (95% CI 0.96–1.50; P=.12); DFS HR 1.05 (95% CI 0.90–1.22; P=.54). The study supported statistical equivalence of outcomes in the SLN-negative population.
The major treatment-burden endpoint was surgical morbidity. Blue-dye allergic reactions were the most common adverse event; removing fewer axillary nodes avoids the morbidity of ALND.
NNT/NNH: NNT: not applicable. This was a surgical de-escalation/equivalence question; a meaningful benefit NNT is not established from the small survival differences.
The clinically important subgroup is patients with a negative SLN; the results do not justify omitting ALND when the SLN is positive. The trial had adequate scale for survival and regional-control assessment.
The primary survival analysis was restricted to pathologically SLN-negative patients; practice in SLN-positive disease was addressed by later trials such as Z0011. Older systemic therapy and surgical practice also limit direct extrapolation.
For clinically node-negative breast cancer with a negative SLN, completion ALND adds axillary surgery without a demonstrated survival or regional-control advantage.