Sentinel node biopsy after neoadjuvant treatment in breast cancer: Five-year follow-up of patients with clinically node-negative or node-positive disease before treatment.

PURPOSE: It is controversial whether sentinel node biopsy (SNB) without axillary dissection (AD) should be performed in cN1/2 breast cancer patients who become cN0 after neoadjuvant treatment, since the false negative rate (FNR) may be unacceptably high. We assessed outcomes to address this issue.

METHODS

We retrospectively assessed 396 cT1-4, cN0/1/2 patients, who became or remained cN0 after neoadjuvant treatment and underwent SNB with at least one sentinel node (SN) found, and AD not performed if the SN was negative.

RESULTS

After a median follow-up of 61 months (interquartile range 38-82), five-year overall survival was 90.7% (95% CI, 87.7-93.7) in the whole cohort, 93.3% (95% CI, 90.0-96.6) in those initially cN0, and 86.3% (95% CI, 80.6-92.1) in those initially cN1/2 (P = 0.12). Axillary failure occurred in only 1 (0.7%) initially cN1/2 patient who became cN0. In initially cN0 patients, and also initially cN1/2 patients who responded well to neoadjuvant treatment (ypT0/ypTx), SN-negativity was a significant predictor of good outcome, consistent with the known prognostic significance of axillary status, and suggesting that SN status accurately reflected axillary status. By contrast, in initially cN1/2 patients found to be ypT1/2/3, SN status (and whether or not AD was performed) had no influence on survival.

CONCLUSIONS

These findings suggest that SNB is acceptable in cN1/2 patients who become cN0 after neoadjuvant therapy.