Sentinel Node Biopsy in Early Breast Cancer: Does Tumor Burden in Sentinel Node Predict the Number of Positive Axillary Nodes?
NR Wadhwani, EK Drinka, T Baker, G Aranha, C Ersahin, J Sinacore, E Rajan, A Salhadar, P Rajan. Loyola University Medical Center, Maywood, IL; University of East Anglia, Norwich, England, United Kingdom
Background: The sentinel node (SN) in breast carcinoma is the first lymph node to which cancer is likely to spread from the primary tumor. Current practice dictates that most patients with a positive SN (micro and macro-metastasis) will undergo a complete axillary dissection. The SN biopsy alone is highly sensitive in predicting axillary lymph node status. Our study illustrates the correlation between tumor burden in the SN and the number of additional positive nodes in the axilla.
Design: 56 cases of pT1 breast cancers were studied to determine the size of metastatic tumor in the SN. The SN tumor burden was determined by measuring in millimeters the greatest dimension of the metastasis. The number of positive nodes in the corresponding axillary dissection was then recorded. A simple linear regression analysis was performed on the tumor size in the SN (independent) and the total number of positive lymph nodes in the axilla (dependent).
Results: There is a statistically significant correlation between the size of metastatic tumor in SN and number of positive axillary nodes in pT1 invasive breast cancers (p<0.015). Figure 1 shows the metastatic tumor size in SN on the X axis (MetsizeinSN) with total positive axillary nodes on the Y axis (TotalPosNodes).
Conclusions: In pT1 invasive breast cancer, the size of metastatic tumor in SN positively correlates with the number of positive axillary nodes. Therefore, in this model we can predict the number of total positive lymph nodes in a pT1 breast cancer using the size of the tumor burden in SN. This model has the capacity to further be adjusted for other factors including but not limited to age, race, and type of breast cancer. Based on our evaluation, additional studies are indeed warranted which may require pooling of data from other pT1 data sets so that we may be able to accurately predict the outcome on a case by case basis for pT1 breast cancer.
Monday, March 22, 2010 9:30 AM
Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 39, Monday Morning