Neoadjuvant Treatment of Breast Carcinoma Does Not Affect the Accuracy of Intraoperative Sentinel Lymph Node Evaluation.
Hope T Richard, Dana L Johnson, Michael O Idowu, Celeste N Powers. Virginia Commonwealth University, Richmond
Background: The use of neoadjuvant therapy in breast carcinoma patients with tumors ≥ 2cm has increased significantly. The consequence of this treatment on the accuracy of intraoperative sentinel lymph node (SLN) evaluation is currently a subject of debate. This study evaluates the effects of neoadjuvant therapy on the intraoperative evaluation of SLN.
Design: We reviewed SLN from consecutive breast cancer patients between 1999 and 2010 with and without prior neoadjuvant therapy. The intraoperative diagnoses were then correlated with permanent section to determine the true positive (TP), true negative (TN), false negative (FN) and false positive (FP) rates. The proportion cases with positive lymph nodes on axillary dissection in the non-neoadjuvant (NNA) and neoadjuvant (NA) treated groups was then compared. Isolated tumor cells are included in micrometastasis. Statistical analysis was performed using the Chi square test.
Results: In this study 2169 SLN from 982 consecutive patients were reviewed. No significant difference was noted between the TP and FN rates of the NNA and NA groups (p=0.471). However, a significantly greater percentage of FN lymph nodes in the NA patients (3.5% vs. 1.8%) had metastases >2 mm noted on permanent section (p=0.00653). Additionally, a greater proportion of cases with SLN metastases >2mm had positive lymph nodes on completion axillary dissection as compared to those <2mm in both groups.
|True Positive||False Negative|
|No prior neoadjuvant (NNA) (n=1969 SLN)||142(7%)||25(1.3%)||35(1.8%)||73(3.7%)|
|Neoadjuvant (NA) (n=200 SLN)||14(7%)||6(3%)||7(3.5%)||7(3.5%)|
|No prior neoadjuvant (n=224 cases)||Neoadjuvant (n=23 cases)|
|Macromets on SLN (>2mm)||Micromets on SLN (<2mm)||Macromets on SLN (>2mm)||Micromets on SLN (<2mm)|
|Positive LN on axillary dissection||104(46%)||10(5%)||13(57%)||1(4%)|
|Negative LN on axillary dissection||67(30%)||43(19%)||5(22%)||4(17%)|
|p value||0.34 (SLN >2mm in NA vs NNA and subsequent +axillary LN) & 0.95 (SLN <2mm in NA vs NNA and subsequent + axillary LN)|