Prognostic value of hematogenous dissemination and biological profile of the tumor in early breast cancer patients: a prospective observational study

How much do we know about the metastatic process?

Cancer cells can leave their primary sites and travel through the circulation to distant sites, where they lodge as disseminated cancer cells (DCCs), even during the early and asymptomatic stages of tumor progression. In experimental models and clinical samples, DCCs can be detected in a non-proliferative state, defined as cellular dormancy. This state can persist for extended periods until DCCs reawaken, usually in response to niche-derived reactivation signals. Therefore, their clinical detection in sites like lymph nodes and bone marrow is linked to poor survival. Current cancer therapy designs are based on the biology of the primary tumor and do not target the biology of the dormant DCC population and thus fail to eradicate the initial or subsequent waves of metastasis. In this brief review, we discuss the current methods for detecting DCCs and highlight new strategies that aim to target DCCs that constitute minimal residual disease to reduce or prevent metastasis formation. Furthermore, we present current evidence on the relevance of DCCs derived from early stages of tumor progression in metastatic disease and describe the animal models available for their study. We also discuss our current understanding of the dissemination mechanisms utilized by genetically less- and more-advanced cancer cells, which include the functional analysis of intermediate or hybrid states of epithelial-mesenchymal transition (EMT). Finally, we raise some intriguing questions regarding the clinical impact of studying the crosstalk between evolutionary waves of DCCs and the initiation of metastatic disease.

Radiomics nomogram for predicting axillary lymph node metastasis in breast cancer based on DCE-MRI: A multicenter study

OBJECTIVES

This study aims to develop and validate a radiomics nomogram based on dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) to noninvasively predict axillary lymph node (ALN) metastasis in breast cancer.

METHODS

This retrospective study included 263 patients with histologically proven invasive breast cancer and who underwent DCE-MRI examination before surgery in two hospitals. All patients had a defined ALN status based on pathological examination results. Regions of interest (ROIs) of the primary tumor and ipsilateral ALN were manually drawn. A total of 1,409 radiomics features were initially computed from each ROI. Next, the low variance threshold, SelectKBest, and least absolute shrinkage and selection operator (LASSO) algorithms were used to extract the radiomics features. The selected radiomics features were used to establish the radiomics signature of the primary tumor and ALN. A radiomics nomogram model, including the radiomics signature and the independent clinical risk factors, was then constructed. The predictive performance was evaluated by the receiver operating characteristic (ROC) curves, calibration curve, and decision curve analysis (DCA) by using the training and testing sets.

RESULTS

ALNM rates of the training, internal testing, and external testing sets were 43.6%, 44.3% and 32.3%, respectively. The nomogram, including clinical risk factors (tumor diameter) and radiomics signature of the primary tumor and ALN, showed good calibration and discrimination with areas under the ROC curves of 0.884, 0.822, and 0.813 in the training, internal and external testing sets, respectively. DCA also showed that radiomics nomogram displayed better clinical predictive usefulness than the clinical or radiomics signature alone.

CONCLUSIONS

The radiomics nomogram combined with clinical risk factors and DCE-MRI-based radiomics signature may be used to predict ALN metastasis in a noninvasive manner.

Disseminated tumour cells from the bone marrow of early breast cancer patients: Results from an international pooled analysis

PURPOSE

Presence of disseminated tumour cells (DTCs) in the bone marrow (BM) has been described as a surrogate of residual disease in patients with early breast cancer (EBC). PADDY (Pooled Analysis of DTC Detection in Early Breast Cancer) is a large international analysis of pooled data that aimed to assess the prognostic impact of DTCs in patients with EBC.

EXPERIMENTAL DESIGN

Individual patient data were collected from 11 centres. Patients with EBC and available follow-up data in whom BM sampling was performed at the time of primary diagnosis before receiving any anticancer treatment were eligible. DTCs were identified by antibody staining against epithelial cytokeratins. Multivariate Cox regression was used to compare the survival of DTC-positive versus DTC-negative patients.

RESULTS

In total, 10,307 patients were included. Of these, 2814 (27.3%) were DTC-positive. DTC detection was associated with higher tumour grade, larger tumour size, nodal positivity, oestrogen receptor and progesterone receptor negativity, and HER2 positivity (all p < 0.001). Multivariate analyses showed that DTC detection was an independent prognostic marker for overall survival, disease-free survival and distant disease-free survival with hazard ratios (HR) and 95% confidence intervals (CI) of 1.23 (95% CI: 1.06-1.43, p = 0.006), 1.30 (95% CI: 1.12-1.52, p < 0.001) and 1.30 (95% CI: 1.08-1.56, p = 0.006), respectively. There was no association between locoregional relapse-free survival and DTC detection (HR 1.21; 95% CI 0.68-2.16; p = 0.512).

CONCLUSIONS

DTCs in the BM represent an independent prognostic marker in patients with EBC. The heterogeneous metastasis-initiating potential of DTCs is consistent with the concept of cancer dormancy.

Bone marrow micrometastases do not impact disease-free and overall survival in early stage sentinel lymph node-negative breast cancer patients

BACKGROUND

The presence of lymph node metastases is the most important prognostic factor in early stage breast cancer. Whether bone marrow micrometastases (BMM) impact the prognosis in sentinel lymph node (SLN)-negative breast cancer patients remains a matter of debate. Therefore, the objective of this study was to assess the impact of BMM on 5-year disease-free and overall survival among those patients.

METHODS

We analyzed 410 patients with early stage breast cancer (pT1 and pT2 ≤ 3 cm, cN0) who were prospectively enrolled into the Swiss Multicenter Sentinel Lymph Node Study in Breast Cancer between January 2000 and December 2003. All patients underwent bone marrow aspiration followed by SLN biopsy. All SLN were stained with hematoxylin and eosin and immunohistochemistry (Lu-5, CK-22). Cancer cells in the bone marrow were identified after staining with monoclonal antibodies A45-B/B3 against CK-8, -18, and -19.

RESULTS

Negative SLN were found in 67.6% (277 of 410) of the enrolled patients. Of those, BMM status was negative in 75.8% (210 of 277) and positive in 24.2% (67 of 277) patients. Median follow-up was 61 (range 11-96) months. Five-year disease-free survival was 93.6% (95% confidence interval [CI] 89.1-96.0) in BMM-negative and 92.2% (95% CI 82.5-96.2) in BMM-positive patients (p = 0.50). Five-year overall survival was 92.7% (95% CI 87.9-95.8) for the BMM-negative and 92.5% (95% CI 83.4-96.2) for the BMM-positive group (p = 0.85).

CONCLUSIONS

This is one of the first prospective studies to examine 5-year disease-free and overall survivals in SLN-negative patients in correlation to their BMM status. Although BMM are identified in one of four SLN-negative patients, they do not impact disease-free and overall survival.

Detection of disseminated tumor cells in locally advanced breast cancer patients before primary systemic therapy

AIM

To assess the prevalence and prognostic power of disseminated tumor cells (DTC) in patients with locally advanced breast cancer (LABC) before primary systemic therapy (PST).

MATERIALS AND METHODS

LABC patients attending our Breast Unit were studied between 2002 and 2012, all of them being considered for PST. To determine the presence of DTC, posterior iliac crest aspirates were obtained and marrow samples were processed by gradient separation with Ficoll (Lymphoprep(®)) and immunohistochemical staining using the antiCK A45-B/B3 (EPIMET) antibody. Clinicopathologic variables were recorded before and after PST to assess response. Disease-free survival (DFS) and overall survival (OS) were determined after follow-up. The presence of DTC as a predictor of response to PST and as a prognostic tool for OS and DSF was evaluated.

RESULTS

DTC were observed in 26% of 47 patients included in the study. PST consisted of chemotherapy in 94% and hormone therapy in 6%. Breast-conserving therapy was attained in 33%. Mean follow-up was 68 months. Complete clinical response (CR) after PST was seen in 26%, disease recurrence in 38%, and cancer-related death in 8%; tumor size and negative estrogen receptors were significant predictors of CR and mastectomy was associated with DFS. Persistent axillary disease after PST and previous recurrence were predictive of OS. DTC were detected more often in patients who did not achieve CR and those who presented recurrence. DTC detection was a significant prognostic factor for a worse OS (OR = 7.62; CI95%: 1.46-39.61; p = 0.009) and a decreased survival time (62 versus 82 months, p = 0.004).

CONCLUSION

Presence of DTC before PST was found in a significant number of patients with LABC. DTC were found to be a significant prognostic factor for cancer-related death. DTC could be a surrogate predictor of response to PST and also of disease recurrence in LABC patients.

Analysis of and prognostic information from disseminated tumour cells in bone marrow in primary breast cancer: a prospective observational study

Background

Disseminated tumour cells (DTCs) in the bone marrow of patients with breast cancer have been identified as an independent predictor of poor prognosis in patients with non-metastatic disease. This prospective study aimed to evaluate the presence and prognostic value of DTCs in the bone marrow of female patients with primary breast cancer.

Methods

Between 1999 and 2003, bone marrow aspirates were obtained from patients at the time of surgery for primary invasive breast cancer. DTCs in bone marrow were identified using monoclonal antibodies against cytokeratins for detection of epithelial cells. The detection of DTCs was related to clinical follow-up with distant disease-free survival (DDFS) and breast cancer-specific survival as endpoints. Bone marrow aspirates from adult healthy bone marrow donors were analysed separately.

Results

DTCs were analysed in 401 patients, and cytokeratin-positive cells were found in 152 of these (38%). An immunofluorescence (IF) staining procedure was used in 327 patients, and immunocytochemistry (IC) was performed in 74 patients. The IF-based method resulted in 40% DTC-positive cases, whereas 30% were positive using IC (p = 0.11). The presence of DTCs in bone marrow was not significantly related to patient or tumour characteristics. The presence of DTCs was not a prognostic factor for DDFS (IF: hazards ratio [HR], 2.2; 95% confidence interval [CI], 0.63–2.2; p = 0.60; IC: HR, 0.84; 95% CI, 0.09–8.1; p = 0.88). Significant prognostic factors were lymph node metastases, oestrogen receptor positivity, Nottingham histological grade, and tumour size using Cox univariate analysis. The analyses were positive for epithelial cells in bone marrow from adult healthy donors in 19 (25%) samples.

Conclusions

The detection of DTCs in bone marrow in primary breast cancer was previously shown to be a predictor of poor prognosis. We were not able to confirm these results in a prospective cohort including unselected patients before the standard procedure was established. Future studies with a standardised patient protocol and improved technique for isolating and detecting DTCs may reveal the clinical applications of DTC detection in patients with micrometastases in the bone marrow.