The impact of preoperative breast biopsy on the risk of sentinel lymph node metastases: analysis of 2502 cases from the Austrian Sentinel Node Biopsy Study Group.

Preoperative breast biopsy might cause disaggregation of tumour cells and tumour cell spread. The purpose of this study was to investigate the impact of preoperative biopsy on the rate of metastases to the sentinel lymph node (SLN) of patients with primary breast cancer. We report the results of 2502 patients with primary breast cancer, who were operated, and a sentinel node biopsy was performed. The association of preoperative biopsy with the risk of SLN metastases was examined by regression analyses and tested for possible confounding well-known factors for axillary node metastases. In all, 1890 patients were available for final analyses; 1048 (55.4%) patients had a preoperative diagnosis performed by fine-needle aspiration or core biopsy; 641 (33.9%) patients had a positive SLN when conventional H&E and IHC staining was performed. Patients with preoperative breast biopsy showed a 1.37 times (95% CI, 1.13-1.66) increased risk of SLN metastases on univariate analysis, but this result was not persistent when analysis was adjusted for other relevant factors for axillary node metastases, OR 1.09 (95% CI, 0.85-1.40). In addition, subgroup analyses of the risk for occult micro metastases to the SLN (detected by IHC only) on H&E-negative cases also showed no increased risk associated with preoperative biopsy, OR 1.07 (95% CI, 0.69-1.65). The conclusion, based on the present data, is that preoperative breast biopsy does not cause artificial tumour cell spread to the SLN, with possible negative impact on the prognosis of breast cancer.

LLC-PK1 epithelia as a model for in vitro assessment of proximal tubular nephrotoxicity.

LLC-PK1 cells, an established epithelial cell line derived from pig kidney, were used as a model system for assessment of nephrotoxic side effects of three cephalosporin antibiotics: cephaloridine, ceftazidime, and cefotaxime. Toxic effects of these xenobiotics were monitored on confluent monolayers by light and electron microscopy and by the release of cellular marker enzyme activities into the culture medium. In addition, LLC-PK1 cells were grown on microporous supports, and cephalosporin-induced alteration of epithelial functional integrity was monitored by a novel electrophysiologic approach. For this purpose, an Ussing chamberlike experimental setup was used. The dose-dependent effects on transepithelial ionic permselectivity were monitored under conditions in which defined fractions of the apical culture medium NaCl contents were replaced iso-osmotically by mannitol. This method of determining the functional intactness of the epithelial barrier by measuring dilution potentials was found to be far more sensitive than monitoring cell injury by means of morphology or measurement of enzyme release. As expected from animal experimental data, a dose-dependent disruption of monolayer integrity was detected with all three methodologies applied. Cephaloridine was found the most toxic compound followed by ceftazidime, where a 3-fold, and cefotaxime, where a 10-fold dose of that of cephaloridine was needed to produce cell injury. Measurement of transepithelial dilution potentials was more sensitive as compared to the release of the apical plasma membrane marker enzyme activities alkaline phosphatase and gamma-glutamyltranspeptidase, the cytosolic lactate dehydrogenase, or the mitochondrial glutamate dehydrogenase. The data were compared to the effects of the aminoglycoside antibiotic gentamicin, which at least with respect to its effects on LLC-PK1 morphology and enzyme release, but not transepithelial electrical properties, was already investigated.