1. Extranodal Extension on Sentinel Lymph Node Dissection: Why Should We Treat It Differently? Audrey Choi MD, Matthew Surrusco MD, Samuel Rodriguez MD, Khaled Bahjri MD, MPH, Naveen Solomon MD, Carlos Garberoglio MD, Sharon Lum MD, Maheswari Senthil MD

2. Background »Completion axillary lymph node dissection has remained the standard of care for sentinel lymph node metastasis »ACOSOG Z0011 trial ~T1-T2, breast conservation surgery (BCS) with radiation, underwent sentinel lymph node dissection (SLND) with 1-2 positive SLN ~Randomized to completion axillary lymph node dissection (ALND) or no further surgery ~27% of patients in ALND group had additional nodal burden ~No difference in locoregional recurrence and overall survival at median follow up time (6.3 years)

3. Background »ACOSOG Z0011 showed selected patients with limited axillary nodal burden on SLND can avoid added morbidity of ALND ~Patients with extranodal extension (ENE) on pathology were excluded from the study »Current standard of care is to proceed with ALND if ENE is found on SLND ~Significance of ENE identified on SLND is not well defined

4. Objective »To determine the impact of ENE detected on sentinel lymph node dissection on: ~Axillary nodal burden ~Disease recurrence ~Overall survival

5. Design »Retrospective cross-sectional study, prospectively collected database »Included patients with breast cancer undergoing SLND at Loma Linda University Medical Center »2005-2012 »Statistical analysis ~Adjusted and unadjusted analyses of covariates associated with disease recurrence and overall survival

6. Results All patients with SLND 2005-2012 N=655 No SLN metastasis N=478 (73.0%) SLN metastasis without ENE N=124 (70.1%) SLN metastasis with ENE N=53 (29.9%) SLN metastasis present N=177 (27.0%)

7. Patient demographics Value Age (years) Median57 (26-86) Tumor size in situ4/177 (2.3%) T196/177 (54.2%) T255/177 (31.3%) T312/177 (6.8%) T43/177 (1.7%) Missing7/177 (3.9%) Receptor Status ER+155/177 (87.6%) PR+141/177 (80.0%) Her2/Neu+25/174 (14.4%) Value Grade I31/177 (17.5%) II66/177 (37.3%) III65/177 (36.7%) IV3/177 (1.7%) Missing7/177 (3.9%) Adjuvant therapy Systemic119/167 (71.3%) Radiation108/166 (65.1%)

8. Non-SLN metastasis NSLN metastasis N=26 (57.8%) SLN metastasis without ENE N=124 (70.1%) SLN metastasis with ENE N=53 (29.9%) NSLN metastasis N=37 (44.0%) No further disease N=47 No ALND N=40 No further disease N=19 No ALND N=8 ALND N=84 ALND N=45 SLN metastasis present N=177

9. Increased axillary nodal burden P = 0.01 *

10. Type of recurrence +ENE »ENE associated with increased disease recurrence -ENE

11. Disease recurrence Adjusted analyses of covariates associated with disease recurrence »4 times the odds of experiencing disease recurrence if +ENE on SLND »Trend toward significance on adjusted analysis

12. Overall survival »Over 7 times the odds for decreased survival if +ENE on SLND »Statistically significant after controlling for other factors Adjusted analyses of covariates associated with overall survival

13. Conclusions »Extranodal extension on sentinel lymph node dissection was associated with: ~Increased axillary nodal burden ~Increased disease recurrence ~Associated with poor survival outcome »Extranodal extension on SLND should be considered a poor prognostic factor »Extranodal extension found on SLND still warrants completion axillary lymph node dissection

14. Thank you!