Multicentre study of the risk of invasive cancer and use of sentinel node biopsy in women with a preoperative diagnosis of ductal carcinoma in situ

Background

Ductal carcinoma in situ (DCIS) in the breast that is diagnosed by biopsy implies a risk of upstaging to invasive carcinoma (IC) on final pathology. These patients require a sentinel lymph node biopsy (SLNB) for axillary staging. A two-stage procedure is not always feasible and precise selection of patients who should be offered SLNB is crucial. The aims were: to determine the rate of upstaging, and use of redundant and required SLNB in women with a preoperative diagnosis of DCIS; and to identify patient and tumour characteristics that increase the risk of upstaging.

Methods

Patients with DCIS treated between 2008 and 2016 were identified using Orbit operation planning system software, and those suitable for the study were selected based on review of the medical records. Upstaging rates and proportions of redundant and required SLNBs were calculated. Associations between clinicopathological characteristics and upstaging were analysed using univariable and multivariable logistic regression analyses.

Results

Of 1368 patients initially identified, 975 women with a preoperative diagnosis of DCIS were included in the study. Tumours in 246 of these patients (25·2 per cent) were upstaged to IC. Redundant SLNB was performed in 392 of 975 women (40·2 per cent). Forty-four patients (4·5 per cent) with a final diagnosis of IC were not offered SLNB and thus potentially undertreated. In adjusted analysis, DCIS size, palpability and mass formation identified by breast imaging were associated with increased risk of upstaging. The Van Nuys classification was not associated with upstaging.

Conclusion

Most patients with IC on final pathology underwent SLNB, but a considerable number of patients with DCIS had a redundant SLNB. Lesion size, palpability and mass formation, but not Van Nuys classification group, are suggested risk factors for upstaging.

A predictive tool to estimate the risk of axillary metastases in breast cancer patients with negative axillary ultrasound

BACKGROUND

Sentinel node biopsy (SNB) is the "gold standard" in axillary staging in clinically node-negative breast cancer patients. However, axillary treatment is undergoing a paradigm shift and studies are being conducted on whether SNB may be omitted in low-risk patients. The purpose of this study was to evaluate the risk factors for axillary metastases in breast cancer patients with negative preoperative axillary ultrasound.

METHODS

A total of 1,395 consecutive patients with invasive breast cancer and SNB formed the original patient series. A univariate analysis was conducted to assess risk factors for axillary metastases. Binary logistic regression analysis was conducted to form a predictive model based on the risk factors. The predictive model was first validated internally in a patient series of 566 further patients and then externally in a patient series of 2,463 patients from four other centers. All statistical tests were two-sided.

RESULTS

A total of 426 of the 1,395 (30.5 %) patients in the original patient series had axillary lymph node metastases. Histological size (P < 0.001), multifocality (P < 0.001), lymphovascular invasion (P < 0.001), and palpability of the primary tumor (P < 0.001) were included in the predictive model. Internal validation of the model produced an area under the receiver operating characteristics curve (AUC) of 0.731 and external validation an AUC of 0.79.

CONCLUSIONS

We present a predictive model to assess the patient-specific probability of axillary lymph node metastases in patients with clinically node-negative breast cancer. The model performs well in internal and external validation. The model needs to be validated in each center before application to clinical use.

Cross-validation of three predictive tools for non-sentinel node metastases in breast cancer patients with micrometastases or isolated tumor cells in the sentinel node

BACKGROUND

We cross-validated three existing models for the prediction of non-sentinel node metastases in patients with micrometastases or isolated tumor cells (ITC) in the sentinel node, developed in Danish and Finnish cohorts of breast cancer patients, to find the best model to identify patients who might benefit from further axillary treatment.

MATERIAL AND METHOD

Based on 484 Finnish breast cancer patients with micrometastases or ITC in sentinel node a model has been developed for the prediction of non-sentinel node metastases. Likewise, two separate models have been developed in 1577 Danish patients with micrometastases and 304 Danish patients with ITC, respectively. The models were cross-validated in the opposite cohort.

RESULTS

The Danish model for micrometatases was accurate when tested in the Finnish cohort, with a slight change in AUC from 0.64 to 0.63. The AUC of the Finnish model decreased from 0.68 to 0.58 when tested in the Danish cohort, and the AUC of the Danish model for ITC decreased from 0.73 to 0.52, when tested in the Finnish cohort. The Danish micrometastatic model identified 14-22% of the patients as high-risk patients with over 30% risk of non-sentinel node metastases while less than 1% was identified by the Finish model. In contrast, the Finish model predicted a much larger proportion of patients being in the low-risk group with less than 10% risk of non-sentinel node metastases.

CONCLUSION

The Danish model for micrometastases worked well in predicting high risk of non-sentinel node metastases and was accurate under external validation.

Abstract S5-2: Iatrogenic Displacement of Tumor Cells to the Sentinel Node after Surgical Excision Biopsy in Primary Breast Cancer

Background: It is shown that isolated tumor cells are more common in the sentinel node after needle biopsy of a breast cancer, indicating iatrogenic displacement of epithelial cells. This may result in unnecessary axillary lymph node dissections. It is possible that a similar iatrogenic displacement occurs after surgical excision biopsy but the incidence and clinical significance is basically unknown.

Material and Methods: By linking data from the Danish Breast Cancer Cooporative Group database and data from the Danish National Health Registry we compared the incidence of isolated tumor cells and micrometastases in the sentinel node of 347 breast cancer patients with prior surgical excision biopsy to a group of 14401 patients without prior surgical excision biopsy in a multivariate analysis adjusting for tumor size, receptor status, type and histological grade. The incidence of isolated tumor cells in the sentinel node was further analysed by histological type. Finally, we investigated the incidence of non-sentinel node metastases in patients with isolated tumor cells and micrometastases in the sentinel node after prior surgical excision biopsy.

Results: We found an adjusted odds ratio on 3.99 (95% CI 2.67-5.97; P&lt;0.0001) for having isolated tumor cells in the sentinel node after surgical excision biopsy. Likewise, we found an adjusted odds ratio for having micrometastases on 1.62 (95% CI 1.20 -2.18; P=0.002). Isolated tumor cells were, in general, more common in the sentinel node of lobular carcinomas compared to ductal carcinomas (adjusted OR 3.51; 95% CI 2.80-4.40; P&lt;0.0001). In contrast, the increase in isolated tumor cells after surgical excision biopsy was especially seen in patients with ductal carcinomas with an adjusted odds ratio on 5.41 (95% CI 3.45-8.48; P=0.054) whereas the odds ratio for lobular carcinomas was only 1.53 (95% CI 0.45-5.14) (P=0.054 for heterogeneity). None of the 20 patients with isolated tumor cells in the sentinel node after prior surgical excision biopsy had non-sentinel node metastases compared to 13% in the group without prior surgical excision biopsy (P=0.15). In patients with micrometastases in the sentinel node after prior surgical excision biopsy 13% had non sentinel node metastases compared to 18% in the group without prior surgical excision biopsy (P=0.29).

Conclusions: The 4-fold increase in isolated tumor cells in the sentinel node after surgical excision biopsy indicates that this procedure induces iatrogenic displacement of epithelial cells. This displacement is more common in ductal carcinomas, despite the fact that lobular carcinomas, in general, are more likely to present with isolated tumor cells in the sentinel node. We found no further dissemination to non-sentinel lymph nodes, suggesting that isolated tumor cells in the sentinel node in these women do not indicate further spread of disease. Hence, in case of isolated tumor cells in the sentinel node after prior surgical excision biopsy, omission of axillary lymph node dissection should be considered.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr S5-2.

Anticoagulant properties of rabbit lungs in tissue thromboplastin-induced intravascular coagulation

This study was conducted in order to examine possible anticoagulant properties of the lungs during tissue thromboplastin-induced intravascular coagulation. Rabbit brain tissue thromboplastin (n = 17) or saline (n = 6 + 3) was infused above the right atrium (n = 11 + 3) of the heart or in the arcus aorta (n = 6) for a period of 120 min in non-pregnant New Zealand rabbits. Rabbits infused with tissue thromboplastin responded with significantly (p < 0.05) more excessive changes in a number of haemodynamic variables (heart rate, PaO2,PaCO2, blood pH etc.) compared with rabbits infused with saline. Similarly, the prothrombin time (p < 0.05) and the activated partial thromboplastin time (p < 0.05) were significantly more prolonged in rabbits receiving tissue thromboplastin compared with control animals. Also the concentration of blood platelets (p < 0.05), plasma fibrinogen (p < 0.05), antithrombin (p < 0.05), and protein C (p < 0.05) decreased significantly in thromboplastin-treated animals compared with control animals. In all these haemostatic variables there was a common trend that animals infused with tissue thromboplastin in the arcus aorta responded more excessively than animals infused in the right atrium of the heart, and these deviations were statistically significant for fibrinogen (p < 0.05) and prothrombin time (p < 0.05). Similarly, animals infused with tissue thromboplastin in the arcus aorta had an increased number of microthrombi in the lungs and kidneys compared with animals receiving tissue thromboplastin above the right atrium. As the lungs are the first pass organ when you infuse above the right atrium the results from this study suggest that the lungs play a key role in protecting the organism against excessive tissue thromboplastin-induced activation of coagulation.

Studies of the initial anticoagulant response in tissue-thromboplastin induced intravascular coagulation

The very early anticoagulant response was analysed in non-pregnant female New Zealand rabbits infused with rabbit brain tissue thromboplastin for a period of 10 min (n = 6), 20 min (n = 6), and 30 min (n = 6). The rabbits infused with thromboplastin responded with a significant drop in mean arterial pressure (P < 0.05), an increase in blood PaO2 (P < 0.05) and a decrease in PaCO2 (P < 0.05), while control animals remained stable with respect to these variables. The thromboplastin-treated animals had an immediate drop in platelet count (P < 0.05), plasma fibrinogen (P < 0.05) and a prolongation in prothrombin time (P < 0.05) and activated partial thromboplastin time (P < 0.05). The concentrations in a number of proteins involved in the anticoagulant response (antithrombin, plasminogen, antiplasmin) as well as global fibrinolytic activity did not change significantly following 10, 20 and 30 min infusion of thromboplastin, while the concentration of protein C decreased continuously during the infusion periods (P < 0.05) to reach the lowest level (approximately 60%) in animals infused with thromboplastin for 30 min. The animals infused with tissue thromboplastin had microthrombi in 1-6% of the renal glomeruli, but the number of microthrombi did not differ significantly between animals infused for 10, 20 and 30 min. It is concluded that the protein C system may play a key role during the initial phase of intravascular coagulation and immediate activation of protein C may protect against excessive deposition of fibrin.