Abstract 136P
Background
Clinical trials suggested that sentinel lymph node (SLN) biopsy (SLNB) alone provided non-inferior survival than further axillary lymph node dissection (ALND) among breast cancer patients with negative SLNs. However, the long-term outcomes of these two surgical approaches in breast cancer patients with pathologically negative lymph nodes (pN0) remain uncertain.
Methods
We performed a population-based study using the Surveillance, Epidemiology, and End Results (SEER) 18-registry database. We included patients who received a diagnosis between 2000 and 2015 of pathological stage T1-2N0M0 breast cancer and adopted a breast-conserving surgery (BCS) or mastectomy. Patients were considered to have undergone an SLNB alone if they had ≤ 5 examined lymph nodes (ELNs), and ALND if they had ≥ 10 ELNs, while others were excluded given an equivocate lymph node surgery approach. Outcomes included overall survival (OS) and breast cancer-specific survival (BCSS). Propensity-score analyses by weighting and matching and multivariable Cox regression were performed to minimize treatment selection bias.
Results
We included 309430 patients, 253501 (81.9%) underwent SLNB and 55929 (18.1%) underwent ALND. The median follow-up time in the weighted cohort was 122 months for SLNB group and 119 months for ALND group, respectively. ALND was associated with significantly lower OS (hazard ratio [HR], 1.13; 95% confidence interval [CI], 1.10-1.16; 10-year OS, 78.2%; 95% CI, 77.8%-78.6%) and lower BCSS (HR, 1.16; 95% CI, 1.10-1.22; 10-year BCSS, 93.4%; 95% CI, 93.1%-93.6%) compared with SLNB alone (10-year OS, 80.4%; 95% CI, 80.2%-80.6%; 10-year BCSS, 94.2%; 95% CI, 94.1%-94.3%). Both the propensity score-matching model and multivariable Cox model demonstrated a survival benefit for SLNB group compared with ALND group. Subgroup analyses for key variables did not change these findings.
Conclusions
SLNB was associated with a significantly lower risk of death than ALND in breast cancer patients with pN0 disease. Our study first provides evidence of survival benefit, supporting that SLNB alone is a better option for patients with no metastatic lymph nodes identified after breast cancer operation.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Shusen Wang.
Funding
The National Natural Science Funds of China.
Disclosure
All authors have declared no conflicts of interest.