Validation of the S classification of sentinel lymph node and microanatomic location of sentinel lymph node metastases to predict additional lymph node involvement and overall survival in breast cancer patients.

BACKGROUND: Most patients with a positive sentinel lymph node (SN) have no further metastases in the axillary lymph nodes and may therefore not benefit from axillary lymph node dissection. In patients with melanoma, evaluation of the centripetal depth of tumor invasion in the SN, also known as the S classification of SN, and microanatomic localization of SN metastases were shown to predict non-SN involvement. This phenomenon has been less extensively studied in breast cancer. We sought to validate the S classification and microanatomic location of SN metastases in breast cancer patients with regard to their predictive value for non-SN involvement and overall survival (OS). METHODS: A total of 236 patients with positive SN followed by axillary lymph node dissection were reevaluated according to the S classification and the microanatomic location of SN (subcapsular, parenchymal, combined subcapsular and parenchymal, multifocal, extensive) metastases to predict the likelihood of non-SN metastases and OS. RESULTS: S classification and the microanatomic location of SN metastases were significantly correlated with non-SN status (P < 0.001). Especially patients with a maximum depth of invasion ≤0.3 mm (stage I according to the S classification) and those with SN metastases only in subcapsular location had a low probability of further non-SN metastases (7.8 and 6.1%) and a good prognosis for OS. CONCLUSIONS: S classification and microanatomic location of SN metastases predicts the likelihood of non-SN involvement. Especially patients with subcapsular or S stage I metastases have a low probability of non-SN metastases and a good prognosis for OS.

A nonrandomized follow-up comparison between standard axillary node dissection and sentinel node biopsy in breast cancer.

INTRODUCTION: In many countries sentinel node biopsy (SNB) has become the standard of care in breast cancer based on a large number of observational studies but without results from prospective randomized trials. The goal of our study was to evaluate the oncological safety of the SNB in breast cancer in a multicenter, nonrandomized setting with comparable groups. PATIENTS AND METHODS: Between 1996/05 and 2004/11, 2942 patients from 14 departments in Austria with unicentric, unilateral, invasive disease without neoadjuvant therapy were collected in a database. The recommendations of the Austrian Sentinel Node Study Group were to complete a training period (phase I) with 50 cases of SNB followed by axillary lymph node dissection (ALND) to prove a detection rate of > or = 90% and a false-negative rate of < or = 5%. In the executing period (phase II), SNB was followed by ALND only if the sentinel node (SN) contained metastases. We compared the results on disease-free survival, local recurrence rates, distant recurrence rates and overall survival of both groups. Cases from phases I and II generated groups I (n=671) and 2 (n=2271 cases), respectively. RESULTS: Overall mean follow-up time: 34.41 months. CONCLUSION: SNB followed by ALND only in cases with metastases in the SN is a safe procedure and at least equal to ALND in all cases.