The optimal number of sentinel lymph nodes for focused pathologic examination

The sentinel lymph node (SLN) procedure provides an alternative method for assessing the axillary lymph nodes in patients with breast cancer. The SLN is typically subjected to a focused pathologic examination involving the examination of multiple tissue levels and/or keratin immunohistology. The number of SLNs submitted may vary widely, in some cases rivaling that of a complete axillary dissection (CAD). We examined our experience over the last 2 years in order to determine the optimal number of SLNs for focused pathologic evaluation. All SLN cases for the years 2000 and 2001 were retrieved from the files of the Pathology Department at Magee-Womens Hospital and were tabulated to determine the average number of SLNs per case, the number of SLNs submitted, the actual SLN that was positive for each case, the type of metastasis, and the average number of SLNs per case for each surgeon. There were 662 operative cases that yielded 1576 SLN accessions and 1758 total SLNs. The range of SLNs submitted was 1 to 11. Overall there was a mean of 2.4 SLNs accessioned per case and a mean of 2.7 SLNs per case. A study of the statistics of SLNs submitted by seven surgeons yielded two distinct groups, with one group submitting virtually all of the cases where there were consistently more than four SLNs per case. Ninety-seven percent of positive SLNs were discovered in the first three SLNs submitted, regardless of surgeon identity. The SLNs beyond numbers one to three yielded positive results by keratin in only four cases. Focused pathologic examination of SLNs was most effective for the first three SLNs submitted for any given case. The variation in the number of SLNs submitted per case was different based upon the different practice patterns of surgeons. It is suggested that for more than three SLNs submitted, simple routine lymph node examination would be appropriate.