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Notizen: Abstract:  The sentinel lymph node (SLN) procedure is a method for ascertaining the axillary lymph node status in patients with breast cancer. Intraoperative examination of the SLN may be important, because a positive result directs surgery to a complete axillary lymph node dissection. Intraoperative cytologic examination (IOCE) is a method of intraoperative evaluation, although little data are available regarding the sensitivity of the method with respect to tumor size and the size of the SLN metastasis. All SLN cases for the years 1997–2002 at Magee-Womens Hospital were tabulated for primary breast carcinoma size, IOCE result, final histologic result, and size of the SLN metastasis. All SLNs had IOCE with touch imprints. Scrape SLN preparations and frozen sections were strongly discouraged. There were 748 SLN cases comprising 1576 SLNs that had IOCE, and there were 247 true positive SLN cases comprising 522 SLNs. Of the 247 true positive SLN cases, 111 had a positive IOCE (111/247; 45% sensitivity overall) and there were 136 false negatives. Of the 247 cases, 164 were SLN micrometastases ≤2.0 mm in size, and 44 (27%) of these were detected by IOCE, while the remaining 120 cases were false negative. Of the 83 SLN macrometastases (〉2.0 mm), 66 (80%) were detected by IOCE, with 17 false negatives. In this series, 15 cases (2%) were given the IOCE diagnosis of atypical/defer, and all of these permanent sections were histologically positive. There were five IOCE-positive cases that were histologically negative. Of the 164 SLNs with micrometastases ≤2.0 mm, 17.6% (29/164) were ≤0.5 mm (6/29 [21.4%] were IOCE positive), 5.5% (9/164) were 0.51–1.0 mm (3/9 [33%] were IOCE positive), and 3.6% (6/164) were 1.1–2.0 mm (2/6 [33%] were IOCE positive). There were 83 SLNs with macrometastases larger than 2.0 mm, and 66/83 (80%) were detected by IOCE. In this group, 22% (18/83) were 2.1–5.0 mm (8/18 [44.4%] were IOCE positive) and 57.8% (48/83) were larger than 5.0 mm (41/48 [85%] were IOCE positive). The mean primary breast tumor size was 15.4 mm, with a mean SLN tumor size of 1.4 mm. There was a significant correlation with tumor size and the presence of SLN metastasis, and a significant correlation with tumor size and size of the SLN metastasis. There was a significant t correlation of primary tumor size and positive IOCE, with the group of negative IOCE cases having a mean tumor size of 14 mm and the positive IOCE group having a mean tumor size of 22 mm. The overall sensitivity of the method was 45%, specificity 99%, positive predictive value 0.99, and negative predictive value 0.80. Sensitivity of the IOCE procedure based on SLN tumor size is as follows: ≤0.5 mm, 21.4%; 0.51–1.0 mm, 33%; 1.1–2.0 mm, 33%; 2.1–5.0 mm, 44.4%; and 〉5.0 mm, 85%. Primary tumor size correlates with a positive SLN status and size of the SLN metastasis. Most false-negative IOCEs are due to micrometastases. Positive IOCE cases had a significantly larger SLN metastasis size (mean 8.0 mm) than the false-negative IOCE group (mean 1.4 mm). The IOCE of SLNs has a high negative predictive value, but this is a poor test for the detection of micrometastases, as this group accounts for the majority of false-negative IOCEs of breast SLNs. 

Notizen: Abstract:   The sentinel lymph node biopsy (SLNB) procedure is an alternative method for assessing the axillary lymph node (ALN) status in patients with breast cancer. The SLNB carries the risk of a false-negative result, with patients harboring positive ALNs in the face of a negative SLNB examination. In addition, the significance of a SLNB with cells identified only with keratin or with deposits less than 0.2 mm remains unresolved. We analyzed our SLNB data over the past 5 years in order to determine the relationship between SLN tumor burden and ALN tumor burden. Pathology files for the past 5 years at Magee-Womens Hospital were searched for all SLNB cases that had an axillary lymph node dissection (ALND). Each SLNB case was reviewed and tabulated for breast tumor size, SLN tumor size, and largest tumor size in the ALND. Correlation and frequency distribution were performed for the status of all SLNs and ALNDs. Patterns of lymph node metastasis were recorded and the sizes of the SLN metastases were reported according to the recent Philadelphia Consensus Conference on Sentinel Lymph Nodes and the revised American Joint Committee on Cancer (AJCC) staging. SLN metastases were classified as immunohistochemistry (IHC) positive if only single keratin-positive cells or clusters were present and were not observed with standard tissue stains, as submicrometastatic (SMM) if tumors were less than 0.2 mm (excluding IHC positive), as micrometastatic if tumors were larger than 0.2 mm but ≤2 mm, or as macrometastatic if tumors were larger than 2 mm. A total of 445 patients had both SLNB and ALND. Fifty percent (224/445) of cases were SLN positive, including 58 SLN positive/ALN positive cases and 166 SLN positive/ALN negative cases. Of the 221 patients in the SLN-negative group, 4 were ALN positive (false-negative SLN). The incidence of SLN metastases increased with tumor stage, with the percentage of SLN positives as follows: T1a, 2.1%; T1b, 10.9%; T1c, 51.7%; and T2, 35.3%. There were 4 of 41 patients (10%) with SLNs that were IHC positive that had macrometastases in a solitary ALN. Three of 22 patients (13.6%) that were SMM positive had ALN macrometastasis in a solitary ALN. Four of 49 patients (8.1%) with micrometastatic SLNs had a solitary positive ALN, 3 of which were macrometastases (6.1%). Overall a total of 10 of 112 patients (9.0%) with traditionally defined SLN micrometastases of 2.0 mm or less had a solitary ALN macrometastasis. The vast majority (90%) of these macrometastases were found with T1c and T2 breast tumors. There was a significant difference in the means of SLN tumor sizes for the SLN-positive/ALND-negative (4.5 mm) versus SLN-positive/ALND-positive (10.1 mm) patients, although the range of SLN tumor sizes within each group were similar. There is an increasing incidence of SLN-positive and ALN-positive cases with increasing T stage. Overall in this series, 9% of patients with SLN metastases ≤2 mm had a solitary axillary macrometastasis. Ninety percent of these metastases occurred with T1c/T2 breast tumors, indicating the important codependence of T stage. Overall there is a subset of patients who are IHC positive, SMM positive, or micrometastatic positive with ALNs that are macrometastatic who are at risk of harboring axillary macrometastases. Keratin IHC of breast SLNs is useful for defining these subsets.