Should triple-negative breast cancer (TNBC) subtype affect local-regional therapy decision making?

Influence of tumor microenvironment on the different breast cancer subtypes and applied therapies

Despite the significant improvements made in breast cancer therapy during the last decades, this disease still has increasing incidence and mortality rates. Different targets involved in general processes, like cell proliferation and survival, have become alternative therapeutic options for this disease, with some of them already used in clinic, like the CDK4/6 inhibitors for luminal A tumors treatment. Nevertheless, there is a demand for novel therapeutic strategies focused not only on tumor cells, but also on their microenvironment. Tumor microenvironment (TME) is a very complex and dynamic system that, more than surrounding and supporting tumor cells, actively participates in tumor development and progression. During the last decades, it has become clear that the cellular and acellular components of TME differ between the various breast cancer subtypes and shape the differences regarding their severity and prognosis. The pivotal role of the TME in controlling tumor growth and influencing responses to therapy represents a potential source for novel targets and therapeutic strategies. In this review, we present a description of the multiple therapeutic options used for different breast cancer subtypes, as well as the influence that the TME may exert on the development of the disease and on the response to the distinct therapies, which in some cases may explain their failure by the occurrence of relapses and resistance. Furthermore, the ongoing studies focused on the use of TME components for developing potential cancer treatments are described.

Paraoxonase-2 is upregulated in triple negative breast cancer and contributes to tumor progression and chemoresistance

Triple negative breast cancer (TNBC) displays a high aggressive behavior, tendency to relapse and early metastasize, leading to poor prognosis. The lack of estrogen receptors, and human epidermal growth factor receptor 2, prevents the use of endocrine or molecular targeted therapy, being therapeutical options for TNBC managements mostly limited to surgery, radiotherapy and mainly chemotherapy. While an important number of TNBCs initially responds to chemotherapy, they are prone to develop chemoresistance over the time. Thus, there is an urgent need to identify novel molecular targets to improve the outcome of chemotherapy in TNBC. In this work we focused on the enzyme paraoxonase-2 (PON2) which has been reported to be overexpressed in several tumors contributing to cancer aggressiveness and chemoresistance. Through a case-control study, we analyzed PON2 immunohistochemical expression in breast cancer molecular subtypes Luminal A, Luminal B, Luminal B HER2+, HER2 + and TNBC. Subsequently, we evaluated the in vitro effect of PON2 downregulation on cell proliferation and response to chemotherapeutics. Our results showed that the PON2 expression levels were significantly upregulated in the infiltrating tumors related to the subtypes Luminal A, HER2+ and TNBC compared to the healthy tissue. Furthermore, PON2 downregulation led to a decrease in cell proliferation of breast cancer cells, and significantly enhanced the cytotoxicity of chemotherapeutics on the TNBC cells. Although further analyses are necessary to deeply understand the mechanisms by which the enzyme could participate to breast cancer tumorigenesis, our results seem to demonstrate that PON2 could represent a promising molecular target for TNBC treatment.

Monoclonal antibodies in breast cancer: A critical appraisal

In breast cancer, mAbs can play multifunctional roles like targeting cancer cells, sometimes directly attacking them, helping in locating and delivering therapeutic drugs to targets, inhibiting cell growth and blocking immune system inhibitors, etc. Monoclonal antibodies are also one of the important successful treatment strategies especially against HER2 but they have not been explored much for other types of breast cancers especially in triple negative breast cancers. Monoclonal antibodies impact the feasibility of antigen specificity, bispecific and trispecific mAbs have opened new doors for more targeted specific efficacy. Monoclonal antibodies can be used diversly and with efficacy as compared to other methods of treatment thus maining it a suitable candidate for breast cancer treatment. However, mAbs treatment also causes various side effects such as fever, trembling, fatigue, headache and muscle pain, nausea/vomiting, difficulty in breathing, rashes and bleeding. Understanding the pros and cons of this strategy, we have explored in this review, the current and future potential capabilities of monoclonal antibodies with respect to diagnosis and treatment of breast cancer. DATA AVAILABILITY: Not applicable.

Impact of Locoregional Treatment on Survival in Young Patients with Early-Stage Breast Cancer undergoing Upfront Surgery

BACKGROUND

Randomized, controlled trials comparing breast-conserving therapy (BCT) with mastectomy have demonstrated equivalent overall survival (OS), but recent observational studies have shown improved OS in patients undergoing BCT. These studies provide limited data on young patients who are traditionally offered mastectomy due to perceived higher disease risk. This study examines the OS in a contemporary series of young women with breast cancer undergoing upfront BCT compared with mastectomy.

METHODS

Women ≤40 years old with primary invasive T1-T2, N0-N1 breast cancer were identified from the National Cancer Database between 2006 and 2016. Patient cohorts were based according to locoregional treatment: BCT, mastectomy alone (Mx), and mastectomy with radiotherapy (Mx/RT). Kaplan-Meier method followed by Cox proportional-hazards regression with inverse probability of treatment weighting (IPTW) were performed to account for treatment selection bias effects in OS.

RESULTS

A total of 15,611 patients met the study criteria; 9,509 patients (60.9%) had BCT, 4,020 (25.8%) had Mx/RT, and 2,082 (13.3%) had Mx alone. The median follow-up was 4.6 years (interquartile range [IQR] 3.0-6.4). After IPTW-adjustment, the 5-year OS was similar for BCT (95%), Mx (95%), and Mx/RT (94%), and there was no significant difference in OS in Mx (hazard ratio [HR] = 1.16, 95% confidence interval [CI] 0.90-1.51) and Mx/RT (HR = 1.08, 95% CI 0.88-1.34) compared with BCT. Mx/RT was associated with decreased survival in patients with pT2N0 (HR = 1.78, 95% CI 1.12-2.84).

CONCLUSIONS

Among young patients with early-stage breast cancer, overall survival was equivalent regardless of surgical approach. Breast-conserving therapy remains a safe option in young women despite the clinical tendency to offer upfront mastectomy in young patients.

Emergence of Nanotechnology as a Powerful Cavalry against Triple-Negative Breast Cancer (TNBC)

Triple-negative breast cancer (TNBC) is considered one of the un-manageable types of breast cancer, involving devoid of estrogen, progesterone, and human epidermal growth factor receptor 2 (HER 2) receptors. Due to their ability of recurrence and metastasis, the management of TNBC remains a mainstay challenge, despite the advancements in cancer therapies. Conventional chemotherapy remains the only treatment regimen against TNBC and suffers several limitations such as low bioavailability, systemic toxicity, less targetability, and multi-drug resistance. Although various targeted therapies have been introduced to manage the hardship of TNBC, they still experience certain limitations associated with the survival benefits. The current research thus aimed at developing and improving the strategies for effective therapy against TNBC. Such strategies involved the emergence of nanoparticles. Nanoparticles are designated as nanocavalries, loaded with various agents (drugs, genes, etc.) to battle the progression and metastasis of TNBC along with overcoming the limitations experienced by conventional chemotherapy and targeted therapy. This article documents the treatment regimens of TNBC along with their efficacy towards different subtypes of TNBC, and the various nanotechnologies employed to increase the therapeutic outcome of FDA-approved drug regimens.

Triple-negative breast cancer: current treatment strategies and factors of negative prognosis

Breast cancer is the most common cancer in women and the most common cause of death in working-age women. According to the results of immunohistochemical studies, 10-20% of cases revealed a triple-negative type of breast cancer. This subtype is characterized by significant proliferative activity and growth rate, aggressive clinical course, and early metastasis. This leads to a suspicious prognosis and, accordingly, encourages an increase of surgical treatment radicalism and aggressive systemic treatment. This review briefly analyzes existing treatment strategies for triple-negative breast cancer with a focus on surgical treatment. Surgical treatment is an integral part of complex therapy. Currently, the attention of researchers is focused not only on the radicalism of the operation, ensuring long-term survival, but also on achieving a good cosmetic result that determines the quality of life of patients. In this aspect, organ-preserving and prosthetic methods of operations are promising, the feasibility and effectiveness of which are being discussed. The relevance of choosing the optimal method of operation is evidenced by the lack of generally accepted approaches based on informative markers for the prognosis of the course of the disease. Therefore, the choice of the optimal method of surgical treatment taking into account the individual characteristics of the patient and the tumor, indications for chemotherapy, and radiation therapy remains an unresolved issue and requires further research.

Features from MRI texture analysis associated with survival outcomes in triple-negative breast cancer patients

PURPOSE

The purpose of the study is to evaluate the associations between intratumoral or peritumoral textural features derived from pretreatment magnetic resonance imaging (MRI) and recurrence-free survival (RFS) in triple-negative breast cancer (TNBC) patients.

METHODS

Forty-three patients with TNBC who underwent preoperative MRI between February 2008 and March 2014 were included. We performed two-dimensional texture analysis on the intratumoral or peritumoral region of interest (ROI) on axial of T2-weighted image (T2WI), dynamic contrast-enhanced (DCE)-MRI and DCE-MRI subtraction images. We also analyzed histopathological data. Cox proportional hazards models were used to investigate associations with survival outcomes.

RESULTS

Twelve of the 43 patients (27.9%) had recurrence disease, at a median of 32.5 months follow-up (1.4-61.5 months). In univariate analysis, nine texture features in T2WI and DCE-MRI subtraction images were significantly associated with RFS. In multivariate analysis, intratumoral difference entropy in DCE-MRI subtraction images in the initial phase (hazard ratio 11.71; 95% confidence interval (CI) [1.41, 97.00]; p value 0.023) and, peritumoral difference variance in DCE-MRI subtraction images in the delayed phase (hazard ratio 9.60; 95% CI [1.98, 46.51]; p value 0.005), were both independently associated with RFS. Moreover, multivariate analysis revealed the presence of lymphovascular invasion as independently associated with RFS (hazard ratio 8.13; 95% CI [2.16, 30.30]; p value 0.002).

CONCLUSIONS

At pretreatment MRI, an intratumoral and peritumoral quantitative approach using texture analysis has the potential to serve as a prognostic marker in patients with TNBC.

Kinetic volume analysis on dynamic contrast-enhanced MRI of triple-negative breast cancer: associations with survival outcomes

OBJECTIVE

To evaluate the associations between computer-aided diagnosis (CAD)-generated kinetic volume parameters and survival in triple-negative breast cancer (TNBC) patients.

METHODS

40 patients with TNBC who underwent pre-operative MRI between March 2008 and March 2014 were included. We analyzed CAD-generated parameters on dynamic contrast-enhanced MRI, visual MRI assessment, and histopathological data. Cox proportional hazards models were used to determine associations with survival outcomes.

RESULTS

12 of the 40 (30.0%) patients experienced recurrence and 7 died of breast cancer after a median follow-up of 73.6 months. In multivariate analysis, higher percentage volume (%V) with more than 200% initial enhancement rate correlated with worse disease-specific survival (hazard ratio, 1.12; 95% confidence interval, 1.02-1.22; p-value, 0.014) and higher %V with more than 100% initial enhancement rate followed by persistent curve type at 30% threshold correlated with worse disease-specific survival (hazard ratio, 1.33; 95% confidence interval, 1.10-1.61; p-value, 0.004) and disease-free survival (hazard ratio, 1.27; 95% confidence interval, 1.12-1.43; p-value, 0.000).

CONCLUSION

CAD-generated kinetic volume parameters may correlate with survival in TNBC patients. Further study would be necessary to validate our results on larger cohorts.

ADVANCES IN KNOWLEDGE

CAD generated kinetic volume parameters on breast MRI can predict recurrence and survival outcome of patients in TNBC. Varying the enhancement threshold improved the predictive performance of CAD generated kinetic volume parameter.

How shall we treat early triple-negative breast cancer (TNBC): from the current standard to upcoming immuno-molecular strategies

Triple-negative breast cancer (TNBC) is a long-lasting orphan disease in terms of little therapeutic progress during the past several decades and still the standard of care remains chemotherapy. Experimental discovery of molecular signatures including the ‘BRCAness’ highlighted the innate heterogeneity of TNBC, generating the diversity of TNBC phenotypes. As it contributes to enhancing genomic instability, it has widened the therapeutic spectrum of TNBC. In particular, unusual sensitivity to DNA damaging agents was denoted in patients with BRCA deficiency, suggesting therapeutic benefit from platinum and poly(ADP-ribose) polymerase inhibitors. However, regardless of enriched chemosensitivity and immunogenicity, majority of patients with TNBC still suffer from dismal clinical outcomes including early relapse and metastatic spread. Therefore, efforts into more precise and personalised treatment are critical at this point. Accordingly, the advance of multiomics has revealed novel actionable targets including PI3K-Akt-mTOR and epidermal growth factor receptor signalling pathways, which might actively participate in modulating the chemosensitivity and immune system. Also, TNBC has long been considered a potential protagonist of immunotherapy in breast cancer, supported by abundant tumour-infiltrating lymphocytes and heterogeneous tumour microenvironment. Despite that, earlier studies showed somewhat unsatisfactory results of monotherapy with immune-checkpoint inhibitors, consistently durable responses in responders were noteworthy. Based on these results, further combinatorial trials either with other chemotherapy or targeted agents are underway. Incorporating immune-molecular targets into combination as well as refining the standard chemotherapy might be the key to unlock the future of TNBC. In this review, we share the current and upcoming treatment options of TNBC in the framework of scientific and clinical data, especially focusing on early stage of TNBC.

Perfusion Parameters on Breast Dynamic Contrast-Enhanced MRI Are Associated With Disease-Specific Survival in Patients With Triple-Negative Breast Cancer

OBJECTIVE

The aim of this study was to investigate the association between perfusion parameters on MRI performed before treatment and survival outcome (disease-free survival [DFS], disease-specific survival [DSS]) in patients with triple-negative breast cancer (TNBC).

MATERIALS AND METHODS

Sixty-one patients (median age, 50 years; age range, 27-77 years) with TNBC (tumor size on MRI: median, 25.5 mm; range, 11.0-142.0 mm) were included. We analyzed clinical and pathologic variables and MRI parameters. Cox proportional hazards models were used to determine associations with survival outcome.

RESULTS

The median follow-up time was 46.1 months (range, 13.9-58.4 months). Eleven of 61 (18.0%) patients had events (i.e., local, regional, or distant recurrence or contralateral breast cancer) and seven (11.5%) died of breast cancer. Among the pretreatment variables, a larger tumor size on MR images (hazard ratio [HR] = 1.024, p = 0.003) was associated with worse DFS at univariate analysis. In multivariate pretreatment models for DSS, a higher fractional volume of extravascular extracellular space per unit volume of tissue (v_e) value (HR = 1.658, p = 0.038), higher peak enhancement (HR = 1.843, p = 0.018), and a larger tumor size on MR images (HR = 1.060, p = 0.001) were associated with worse DSS. In multivariate posttreatment models, a larger pathologic tumor size (HR for DFS, 1.074 [p = 0.005]; HR for DSS, 1.050 [p = 0.042]) and metastasis in surgically resected axillary lymph nodes (HR for DFS, 5.789 [p = 0.017]; HR for DSS, 23.717 [p = 0.005]) were associated with worse survival outcome.

CONCLUSION

A higher v_e value, higher peak enhancement, and larger tumor size of the primary tumor on pretreatment MRI were independent predictors of worse DSS in patients with TNBC.

Comparisons of Oncologic Outcomes between Triple-Negative Breast Cancer (TNBC) and Non-TNBC among Patients Treated with Breast-Conserving Therapy

PURPOSE

The optimum local surgical strategy regarding breast-conserving therapy (BCT) for triple-negative breast cancer (TNBC) is controversial. To investigate whether BCT is appropriate for patients with TNBC, we evaluated the clinical outcomes of BCT in women with TNBC compared to those of women without TNBC, using a large, single-center cohort.

MATERIALS AND METHODS

We performed a retrospective analysis of 1533 women (TNBC n=321; non-TNBC n=1212) who underwent BCT for primary breast cancer between 2000 and 2010. Clinicopathological characteristics, locoregional recurrence-free survival (LRFS), and overall survival (OS) were analyzed.

RESULTS

Tumors from the TNBC group had a higher T stage (T2 37.4% vs. 21.0%, p<0.001), a lower N stage (N0 86.9% vs. 75.5%, p<0.001), and a higher histologic grade (Grade III 66.8% vs. 15.4%, p<0.001) than the non-TNBC group. There were no differences in 5-year LRFS rates between the TNBC and non-TNBC groups (98.7% vs. 97.8%, p=0.63). The non-TNBC group showed a slightly better 5-year OS than the TNBC group; however, the difference was not significant (96.2% vs. 97.3%, p=0.72). In multivariate analyses, TNBC was not associated with poor clinical outcomes in terms of LRFS and OS [hazard ratio (HR) for LRFS=0.37, 95% confidence interval (CI): 0.10-1.31; HR for OS=1.03, 95% CI: 0.31-3.39].

CONCLUSION

TNBC patients who underwent BCT showed non-inferior locoregional recurrence compared to non-TNBC patients with BCT. Thus, BCT is an acceptable surgical approach in patients with TNBC.

Breast parenchymal signal enhancement ratio at preoperative magnetic resonance imaging: association with early recurrence in triple-negative breast cancer patients

BACKGROUND

The signal enhancement ratio (SER) of surrounding non-tumor parenchyma at breast magnetic resonance imaging (MRI) can be helpful in breast cancer patients, but has not been investigated in patients with triple negative breast cancer (TNBC).

PURPOSE

To investigate the association between background parenchymal SER around the tumor on preoperative dynamic contrast-enhanced MRI with recurrence-free survival in patients with TNBC.

MATERIAL AND METHODS

Between April 2012 and May 2013, 71 TNBC patients who underwent preoperative MRI were included. SER values were calculated from regions of interest placed in the breast parenchyma around the tumor. Cox proportional hazards models were used to determine associations between MRI variables, clinical-pathologic variables, and recurrence-free survival.

RESULTS

Recurrence occurred in 8.5% (6/71) of patients. At univariate analysis, a higher SER around the tumor, larger tumor size, lymphovascular invasion, lymph node metastasis, receipt of neoadjuvant chemotherapy, receipt of total mastectomy, and not receiving adjuvant chemotherapy were associated with worse recurrence-free survival. At multivariate analysis of preoperative variables, a higher SER around the tumor was independently associated with worse recurrence-free survival (hazard ratio [HR] = 7.072, P = 0.003 for SER1; HR = 6.268, P = 0.006 for SER2; HR = 3.004, P = 0.039 for SER3).

CONCLUSION

Higher SER around the tumor at preoperative dynamic contrast-enhanced MRI is an independent predictor for recurrence in TNBC patients.

The value of adjuvant radiotherapy on survival and recurrence in triple-negative breast cancer: A systematic review and meta-analysis of 5507 patients

BACKGROUND

The value of adjuvant radiotherapy in triple negative breast cancer (TNBC) remains unclear. A systematic review and meta-analysis was conducted in TNBC patients to assess survival and recurrence outcomes associated with radiotherapy following either breast conserving therapy (BCT) or post-mastectomy radiotherapy (PMRT).

METHODS

Four electronic databases were searched from January 2000 to November 2015 (PubMed, MEDLINE, EMBASE and Web of Science). Studies investigating overall survival and/or recurrence in TNBC patients according to radiotherapy administration were included. A random effects meta-analysis was conducted using mastectomy only patients as the reference.

RESULTS

Twelve studies were included. The pooled hazard ratio (HR) for locoregional recurrence comparing BCT and PMRT to mastectomy only was 0.61 (95% confidence interval [CI] 0.41-0.90) and 0.62 (95% CI 0.44-0.86), respectively. Adjuvant radiotherapy was not significantly associated with distant recurrence. The pooled HR for overall survival comparing BCT and PMRT to mastectomy only was 0.57 (95% CI 0.36-0.88) and HR 1.12 (95% CI 0.75, 1.69). Comparing PMRT to mastectomy only, tests for interaction were not significant for stage (p=0.98) or age at diagnosis (p=0.85). However, overall survival was improved in patients with late-stage disease (T3-4, N2-3) pooled HR 0.53 (95% CI 0.32-0.86), and women <40years, pooled HR 0.30 (95% CI 0.11-0.82).

CONCLUSIONS

Adjuvant radiotherapy was associated with a significantly lower risk of locoregional recurrence in TNBC patients, irrespective of the type of surgery. While radiotherapy was not consistently associated with an overall survival gain, benefits may be obtained in women with late-stage disease and younger patients.