Several models have previously been proposed to predict the probability of non-sentinel lymph node (NSLN) metastases after a positive sentinel lymph node (SLN) biopsy in breast cancer. The aim of this study was to assess the accuracy of two previously published nomograms (MSKCC, Stanford) and to develop an alternative model with the best predictive accuracy in a Czech population. In the basic population of 330 SLN-positive patients from the Czech Republic, the accuracy of the MSKCC and the Stanford nomograms was tested by the area under the receiver operating characteristics curve (AUC). A new model (MOU nomogram) was proposed according to the results of multivariate analysis of relevant clinicopathologic variables. The new model was validated in an independent test population from Hungary (383 patients). In the basic population, six of 27 patients with isolated tumor cells (ITC) in the SLN harbored additional NSLN metastases. The AUCs of the MSKCC and Stanford nomograms were 0.68 and 0.66, respectively; for the MOU nomogram it reached 0.76. In the test population, the AUC of the MOU nomogram was similar to that of the basic population (0.74). The presence of only ITC in SLN does not preclude further nodal involvement. Additional variables are beneficial when considering the probability of NSLN metastases. In the basic population, the previously published nomograms (MSKCC and Stanford) showed only limited accuracy. The developed MOU nomogram proved more suitable for the basic population, such as for another independent population from a mid-European country.

The optimal technique for sentinel lymph node biopsy (SLNB) is still debated. SLNB with peritumoral injection of Patent blue dye was performed in 129 clinically T1-T2 and N0 breast cancers in 127 patients (group A); it was later replaced by combined dye and radiocolloid-guided SLNB preceded by lymphoscintigraphy in 72 breast cancer patients (group B). This study compares these two methods. All patients underwent completion axillary dissection. Means of 1.4 and 1.3 SLNs were identified in groups A and B, respectively. The mean number of non-SLNs for the whole series was 14.9 (range 5-42). The first 53 cases of lymphatic mapping (dye only) comprised the institutional learning period during which the identification rate of at least 1 SLN in 30 consecutive attempts reached 90%. The identification rate for the subsequent 76 group A patients was 92%. The accuracy rate of SLNBs for overall axillary nodal status prediction and the false-negative rate for group A patients (after excluding the learning-phase cases) were 93% and 10%, respectively. All 72 group B cases had at least one SLN identified, and only one false-negative case occurred in this group (accuracy and false-negative rates of 99% and 3%, respectively). Both the dye-only and the combined SLNB methods are suitable for SLN identification, but the latter works better and results in higher accuracy, a higher negative predictive value, and a lower false-negative rate. It is therefore the method of choice.

Retrospective data analysis was performed to determine the minimum number of lymph nodes required for the staging of colorectal carcinomas, and a prospective feasibility study was carried out to identify sentinel nodes in order to clarify whether these may predict the nodal status. From among 240 colorectal carcinoma specimens investigated between 1996 and 1998, 224 tumors were analyzed for their nodal status. Lymphatic mapping with vital patent blue dye injection into the peritumoral sub-serosal layer was performed in 25 patients. Blue nodes were identified by the pathologist in the unfixed specimen immediately after the resection of the bowel and were assessed separately. Of the 123 node-positive carcinomas, 40 had more than 3 nodes involved. The nodal positivity increased substantially when more than 6 nodes were assessed. The cumulative percentage analysis demonstrated that ideally 16 and 13 nodes should be obtained for the identification of any nodal involvement or the involvement of more than 3 nodes, respectively. Lymphatic mapping was successful in 24 patients (96%). Blue nodes were predictive of the nodal status in 19 cases (79%), and were the only sites of metastasis in 2 patients (15% of the node-positive cases). Lymphatic mapping with the vital blue dye technique does not seem to facilitate the staging of colorectal cancers, at least in our patient population with relatively large and deeply infiltrating tumors, and unless the technique is improved or other selective features of lymph nodes are found, all lymph nodes should be assessed. A minimum of 6 nodes, and an optimum of 16 nodes or more, are suggested from these series.

Isolated tumour cells and micrometastases in axillary sentinel nodes carry a low risk of non-sentinel node metastasis. The risk of metastasis to further echelon nodes is higher with macrometastases, especially if there is extracapsular growth and the proportion of involved sentinel nodes is high.

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