Bone marrow micrometastases in early breast cancer-30-year outcome

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.

Circulating tumor cell phenotype detection based on epithelial-mesenchymal transition markers combined with clinicopathological risk has potential to better predict recurrence in stage III breast cancer treated with neoadjuvant chemotherapy: a pilot study

BACKGROUND

The potential value of detecting epithelial-mesenchymal transition (EMT) CTCs in early breast cancer, especially during the neoadjuvant therapy period, requires further investigation. We analyzed dynamic CTC phenotype status, to improve recurrence risk stratification for patients with stage III breast cancers.

METHODS

We enrolled 45 patients with stage III breast cancers from 2 clinical trials undergoing neoadjuvant chemotherapy and utilized the CanPatrol CTC enrichment technique pre- and post-chemotherapy to identify CTC phenotypes, including epithelial CTCs, biphenotypic epithelial/mesenchymal CTCs, and mesenchymal CTCs, in peripheral blood samples. Kaplan-Meier analyses were conducted to explore the prognostic value of dynamic change of CTC count and the proportion of CTCs with different phenotypes. Then, redefine the risk stratification based on CTC status and clinicopathological risk in combination.

RESULTS

Increased proportion of M + CTCs was a high-risk CTC status that was associated with decreased DFS (HR, 3.584; 95% CI, 1.057-12.15). In a combined analysis with clinicopathological risk, patients with high-risk tumors had an elevated risk of recurrence compared to patients with low-risk tumors (HR, 4.482; 95% CI, 1.246-16.12). The recurrence risk could be effectively stratified by newly defined risk stratification criteria, with 5-year DFS of 100.0%, 77.3%, and 50.0%, respectively, for low-risk, mid-risk, and high-risk patients (P = 0.0077). Finally, in the ROC analysis, the redefined risk stratification demonstrated higher predictive significance with an AUC of 0.7727, compared to CTC status alone (AUC of 0.6751) or clinicopathological risk alone (AUC of 0.6858).

CONCLUSION

The proportion of M + CTCs increased after neoadjuvant chemotherapy indicating a higher risk of tumor recurrence. Combining CTC status with clinicopathological risk has potential to redefine the risk stratification of stage III breast cancers and provide improved predictions of relapse.

Effect of Different Liver Resection Modalities on the Prognosis of Patients with Hepatocellular Carcinoma on the Left Lateral Lobe

Purpose

To investigate the effect of different liver resection modalities on the prognosis of left lateral lobe hepatocellular carcinoma (HCC) patients.

Methods

315 patients with HCC on left lateral lobe were divided into open left lateral lobectomy (LLL) group (n=249) and open left hepatectomy (LH) group (n=66). The differences in long-term prognosis between two groups were compared.

Results

The results showed that narrow resection margin (Hazard Ratio (HR):1.457, 95% Confidential Interval (CI): 1.038-2.047; HR:1.415, 95% CI: 1.061-1.887), tumor diameter > 5 cm (1.645, 1.161-2.330; 1.488, 1.123-1.971), multiple tumors (2.021, 1.330-3.073; 1.987, 1.380-2.861), and microvascular invasion (MVI) (1.753, 1.253-2.452; 1.438, 1.087-1.902) are independent risk factors for overall survival (OS) and tumor recurrence (TR), while liver resection modality is not. After propensity score matching, liver resection modality is not an independent risk factor for OS and TR. Further analysis revealed that wide resection margins were achieved in all patients in the LH group but only 59.0% patients in the LLL group. The OS and TR rates were not significantly different between wide patients with resection margins in LLL group and LH group (P=0.766 and 0.919, respectively), but significantly different between patients with narrow resection margins in LLL group and LH group (P=0.012 and 0.017, respectively).

Conclusion

Liver resection modality is not an independent risk factor for the prognosis of patients with HCC on the left lateral lobe as long as wide margins are obtained. Nevertheless, with narrow margins, patients who underwent LH rather than LLL did better.

Quiescent Cancer Cells-A Potential Therapeutic Target to Overcome Tumor Resistance and Relapse

Quiescent cancer cells (QCCs) are nonproliferating cells arrested in the G0 phase, characterized by ki67^low and p27^high. QCCs avoid most chemotherapies, and some treatments could further lead to a higher proportion of QCCs in tumors. QCCs are also associated with cancer recurrence since they can re-enter a proliferative state when conditions are favorable. As QCCs lead to drug resistance and tumor recurrence, there is a great need to understand the characteristics of QCCs, decipher the mechanisms that regulate the proliferative-quiescent transition in cancer cells, and develop new strategies to eliminate QCCs residing in solid tumors. In this review, we discussed the mechanisms of QCC-induced drug resistance and tumor recurrence. We also discussed therapeutic strategies to overcome resistance and relapse by targeting QCCs, including (i) identifying reactive quiescent cancer cells and removing them via cell-cycle-dependent anticancer reagents; (ii) modulating the quiescence-to-proliferation switch; and (iii) eliminating QCCs by targeting their unique features. It is believed that the simultaneous co-targeting of proliferating and quiescent cancer cells may ultimately lead to the development of more effective therapeutic strategies for the treatment of solid tumors.

Neoadjuvant Chemotherapy of Patients with Early Breast Cancer Is Associated with Increased Detection of Disseminated Tumor Cells in the Bone Marrow

Simple Summary

Disseminated tumor cells (DTCs) present in the bone marrow of breast cancer patients are an indicator of minimal residual disease and micrometastatic spread. These cells can already be found at the earliest disease stages and are associated with poorer outcomes. In preclinical models, neoadjuvant chemotherapy was shown to promote micrometastatic spread. The aim of this large single-center retrospective study was to compare the frequency and prognostic significance of DTC detection between patients treated with neoadjuvant chemotherapy and treatment-naive patients.

Abstract

Preclinical data suggest that neoadjuvant chemotherapy (NAT) may promote micrometastatic spread. We aimed to compare the detection rate and prognostic relevance of disseminated tumor cells (DTCs) from the bone marrow (BM) of patients with early-stage breast cancer (EBC) after NAT with that of therapy-naive EBC patients. DTCs were identified from BM samples, collected during primary surgery. Patients who received NAT were compared to patients who received chemotherapy after surgery. In total, 809 patients were analyzed. After NAT, 45.4% of patients were DTC-positive as compared to 19.9% of patients in the adjuvant chemotherapy group (p < 0.001). When sampled in patients who had undergone NAT, the detection of DTCs in the BM was significantly increased (OR: 3.1; 95% confidence interval (CI): 2.1–4.4; p < 0.001). After NAT, DTC-positive patients with ≥2 DTCs per 1.5 × 10⁶ mononuclear cells in their BM had an impaired disease-free survival (HR: 4.8, 95% CI: 0.9–26.6; p = 0.050) and overall survival (HR: 4.2; 95% CI: 1.4–12.7; p = 0.005). The higher rate of DTC-positive patients after NAT as compared to a treatment-naive comparable control cohort suggests that NAT supports tumor cell dissemination into the bone marrow. DTC positivity in BM predicted relapse in various distant organs, implying that tumor cell dissemination was not restricted to the bone marrow.

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.

Regulation of bone metastasis and metastasis suppressors by non-coding RNAs in breast cancer

Breast cancer (BC) is a critical health care issue that substantially affects women worldwide. Though surgery and chemotherapy can effectively control tumor growth, metastasis remains a primary concern. Metastatic BC cells predominantly colonize in bone, owing to their rigid osseous nutrient-rich nature. There are recently increasing studies investigating the context-dependent roles of non-coding RNAs (ncRNAs) in metastasis regulation. ncRNAs, including microRNAs, long non-coding RNAs, circular RNAs, and small interference RNAs, control the BC metastasis via altered mechanisms. Additionally, these ncRNAs have been reported in regulating a unique class of genes known as Metastatic suppressors. Metastasis suppressors like BRMS1, NM23, LIFR, and KAI1, etc., have been extensively studied for their role in inducing apoptosis, inhibiting metastasis, and maintaining homeostasis. In this review, we have emphasized the direct regulation of ncRNAs for effectively controlling the distant spread of BC. Furthermore, we have highlighted the ncRNA-mediated modulation of the metastatic suppressors, thereby delineating their indirect influence over metastasis.

Surgical strategies for hepatocellular carcinoma located in the left lateral lobe: A propensity score-matched and prognostic nomogram study

PURPOSE

For hepatocellular carcinoma (HCC) located in the left lateral lobe, the optimal surgical procedure is still controversial. This study aimed to optimize surgical strategies and to construct a nomogram to predict the postoperative survival of patients with HCC.

METHODS

Between 1 January 2005 and 30 September 2018, a total of 493 patients were enrolled. Propensity score matching (PSM) was performed between the left lateral lobectomy (LLL) and left hepatectomy (LH) groups (1:1). The study endpoints were overall survival (OS), recurrence-free survival (RFS), and safety. A nomogram was generated using a multivariate Cox proportional hazards model. The discriminative ability and calibration of the nomogram were evaluated using C-statistics and calibration plots.

RESULTS

After matching, 87 pairs were included. The LH group had better 1-, 3-, and 5-year OS rates than the LLL group (88%, 73%, and 69% vs. 73%, 57%, and 49%, respectively; p = 0.017). The 1-, 3-, and 5-year RFS rates of the LH group were similar to those of the LLL group (64%, 49%, and 46% vs. 63%, 51%, and 42%, respectively; p = 0.652). There were no significant differences in postoperative complications. Eight factors were integrated into the nomogram and it had good discriminative ability and calibration.

CONCLUSION

Our data revealed that compared to LLL, LH may result in better OS and have similar postoperative complications for HCC. The nomogram may serve as a practical tool for the individual prognostic evaluation of patients with HCC.

Targeting Intercellular Communication in the Bone Microenvironment to Prevent Disseminated Tumor Cell Escape from Dormancy and Bone Metastatic Tumor Growth

Metastasis to the bone is a common feature of many cancers including those of the breast, prostate, lung, thyroid and kidney. Once tumors metastasize to the bone, they are essentially incurable. Bone metastasis is a complex process involving not only intravasation of tumor cells from the primary tumor into circulation, but extravasation from circulation into the bone where they meet an environment that is generally suppressive of their growth. The bone microenvironment can inhibit the growth of disseminated tumor cells (DTC) by inducing dormancy of the DTC directly and later on following formation of a micrometastatic tumour mass by inhibiting metastatic processes including angiogenesis, bone remodeling and immunosuppressive cell functions. In this review we will highlight some of the mechanisms mediating DTC dormancy and the complex relationships which occur between tumor cells and bone resident cells in the bone metastatic microenvironment. These inter-cellular interactions may be important targets to consider for development of novel effective therapies for the prevention or treatment of bone metastases.

Circulating Tumor Cells in Breast Cancer

With active screening for early detection and advancements in treatment, there has been a significant decrease in mortality from breast cancer. However, a significant proportion of patients with non-metastatic breast cancer at time of diagnosis will relapse. Therefore, it is suggested that the dissemination of bloodstream tumor cells (circulating tumor cells, CTCs) undetectable by currently available diagnostic tools occurs during the early stages of breast cancer progression, and may be the potential source of micrometastases responsible for treatment failures. Here, we review the clinical significance of CTCs, as detected by the FDA-approved CellSearch^® System, in both metastatic and non-metastatic breast cancer patients. Studies so far suggest that CTCs are prognostic of poorer outcomes in breast cancer patients; however, there is currently insufficient data to support use of CTC data to guide treatment. Therefore, there are ongoing studies to evaluate the utility of assessing CTC phenotypes to develop personalized breast cancer treatment, which will be reviewed in this chapter.

Analysis of circulating tumor DNA in breast cancer as a diagnostic and prognostic biomarker

Despite all the advances in diagnosis and treatment of breast cancer, a large number of patients suffer from late diagnosis or recurrence of their disease. Current available imaging modalities do not reveal micrometastasis and tumor biopsy is an invasive method to detect early stage or recurrent cancer, signifying the need for an inexpensive, non-invasive diagnostic modality. Cell-free tumor DNA (ctDNA) has been tried for early detection and targeted therapy of breast cancer, but its diagnostic and prognostic utility is still under investigation. This review summarizes the existing evidence on the use of ctDNA specifically in breast cancer, including detection methods, diagnostic accuracy, role in genetics and epigenetics evaluation of the tumor, and comparison with other biomarkers. Current evidence suggests that increasing levels of ctDNA in breast cancer can be of significant diagnostic value for early detection of breast cancer although the sensitivity and specificity of the methods is still suboptimal. Additionally, ctDNA allows for characterizing the tumor in a non-invasive way and monitor the response to therapy, although discordance of ctDNA results with direct biopsy (i.e. due to tumor heterogeneity) is still considered a notable limitation.