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

Radiation therapy for triple-negative breast cancer: from molecular insights to clinical perspectives

INTRODUCTION

Triple-negative breast cancer (TNBC) lacks three common receptors, making traditional treatments less effective. This review highlights the importance of radiotherapy and emerging therapeutic strategies to enhance treatment outcomes in TNBC.

AREAS COVERED

We conducted a literature search on PubMed for publications from 2000 to 2023 to discuss the critical role of radiotherapy in managing TNBC, emphasizing its applications from locoregional control to improving survival rates. The review explores molecular mechanisms underlying TNBC's radiotherapy response, including DNA damage repair and apoptosis, with a focus on BRCA1/2 mutations and Poly (ADP-ribose) polymerase (PARP) inhibition. We summarize preclinical and clinical research on radiosensitization strategies, from gene-targeted therapies to immunotherapy combinations, and the impact of post-mastectomy radiation therapy on locoregional control. The potential of personalized treatment approaches, integrating molecular profiling, targeted radiosensitizers, and the synergistic effects of radiotherapy with immunotherapy, is also discussed.

EXPERT OPINION

Future TNBC treatment strategies should focus on precision medicine, integrating immunotherapy, developing novel radiosensitizers, and targeting biological pathways to overcome radioresistance. The integration of radiomics and artificial intelligence offers promising avenues for enhancing treatment personalization and efficacy, aiming to improve patient outcomes in TNBC.

RUVBL1 ubiquitination by DTL promotes RUVBL1/2-β-catenin-mediated transcriptional regulation of NHEJ pathway and enhances radiation resistance in breast cancer

Radiotherapy effectiveness in breast cancer is limited by radioresistance. Nevertheless, the mechanisms behind radioresistance are not yet fully understood. RUVBL1 and RUVBL2, referred to as RUVBL1/2, are crucial AAA+ ATPases that act as co-chaperones and are connected to cancer. Our research revealed that RUVBL1, also known as pontin/TIP49, is excessively expressed in MMTV-PyMT mouse models undergoing radiotherapy, which is considered a murine spontaneous breast-tumor model. Our findings suggest that RUVBL1 enhances DNA damage repair and radioresistance in breast cancer cells both in vitro and in vivo. Mechanistically, we discovered that DTL, also known as CDT2 or DCAF2, which is a substrate adapter protein of CRL4, promotes the ubiquitination of RUVBL1 and facilitates its binding to RUVBL2 and transcription cofactor β-catenin. This interaction, in turn, attenuates its binding to acetyltransferase Tat-interacting protein 60 (TIP60), a comodulator of nuclear receptors. Subsequently, ubiquitinated RUVBL1 promotes the transcriptional regulation of RUVBL1/2-β-catenin on genes associated with the non-homologous end-joining (NHEJ) repair pathway. This process also attenuates TIP60-mediated H4K16 acetylation and the homologous recombination (HR) repair process. Expanding upon the prior study's discoveries, we exhibited that the ubiquitination of RUVBL1 by DTL advances the interosculation of RUVBL1/2-β-catenin. And, it then regulates the transcription of NHEJ repair pathway protein. Resulting in an elevated resistance of breast cancer cells to radiation therapy. From the aforementioned, it is evident that targeting DTL-RUVBL1/2-β-catenin provides a potential radiosensitization approach when treating breast cancer.

The Association between Early-Onset Diagnosis and Clinical Outcomes in Triple-Negative Breast Cancer: A Systematic Review and Meta-Analysis

Early-onset diagnosis, defined by age <40 years, has historically been associated with inferior outcomes in breast cancer. Recent evidence suggests that this association is modified by molecular subtype. We performed a systematic review and meta-analysis of the literature to synthesize evidence on the association between early-onset diagnosis and clinical outcomes in triple-negative breast cancer (TNBC). Studies comparing the risk of clinical outcomes in non-metastatic TNBC between early-onset patients and later-onset patients (≥40 years) were queried in Medline and EMBASE from inception to February 2023. Separate meta-analyses were performed for breast cancer specific survival (BCSS), overall survival (OS), and disease-free survival (DFS), locoregional recurrence-free survival (LRRFS), distant recurrence-free survival (DRFS), and pathological complete response (pCR). In total, 7581 unique records were identified, and 36 studies satisfied inclusion criteria. The pooled risk of any recurrence was significantly greater in early-onset patients compared to later-onset patients. Better BCSS and OS were observed in early-onset patients relative to later-onset patients aged >60 years. The pooled odds of achieving pCR were significantly higher in early-onset patients. Future studies should evaluate the role of locoregional management of TNBC and the implementation of novel therapies such as PARP inhibitors in real-world settings, and whether they improve outcomes.

Androgen Receptor Status in Triple Negative Breast Cancer: Does It Correlate with Clinicopathological Characteristics?

Purpose

Triple negative breast cancer (TNBC) is a breast carcinoma subtype that neither expresses estrogen (ER) and progesterone receptors (PR) nor the human epidermal growth factor receptor 2 (HER2). Patients with TNBC have been shown to have poorer outcomes mainly owing to the limited treatment options available. However, some studies have shown TNBC tumors expressing androgen receptors (AR), raising hopes of its prognostic role.

Patients and Methods

This retrospective study investigated the expression of AR in TNBC and its relationship with known patient demographics, tumor and survival characteristics. From the records of 205 TNBC patients, 36 had available archived tissue samples eligible for AR staining. For statistical purposes, tumors were classified as either "positive" or "negative" for AR expression. The nuclear expression of AR was scored by measuring the percentage of stained tumor cells and its staining intensity.

Results

AR was expressed by 50% of the tissue samples in our TNBC cohort. The relationship between AR status with age at the time of TNBC diagnosis was statistically significant, with all AR positive TNBC patients being greater than 50 years old (vs 72.2% in AR negative TNBC). Also, the relationship between AR status and type of surgery received was statistically significant. There were no statistically significant associations between AR status with other tumor characteristics including "TNM status", tumor grade or treatments received. There was no statistically significant difference in median survival between AR negative and AR positive TNBC patients (3.5 vs 3.1 years; p = 0.581). The relationship between OS time and AR status (p = 0.581), type of surgery (p = 0.061) and treatments (p = 0.917) were not statistically significant.

Conclusion

The androgen receptor may be an important prognostic marker in TNBC, with further research warranted. This research may benefit future studies investigating receptor-targeted therapies in TNBC.

Treatment for Triple-Negative Breast Cancer: An Umbrella Review of Meta-Analyses

Purpose

In recent years, many meta-analyses of triple-negative breast cancer (TNBC) treatment have been published; however, these studies still lack systematic summary. Therefore, the aim of this study is to summarize and evaluate the evidence level and efficacy of treatment for TNBC.

Materials and Methods

Retrospective and prospective studies on treatment of TNBC were searched in the PubMed, Embase, and Cochrane Library databases. The literature search deadline was June 30, 2021. Two investigators independently screened the literature and extracted the data. In addition, the joint World Health Organization–United Nations Food and Agriculture Organization expert consultation was used to evaluate the validity of the evidence.

Results

A total of 28 meta-analyses were included in this study. The treatment interventions for TNBC mainly included surgery, chemotherapy (CT), radiotherapy, molecular targeted therapy, immunotherapy, zoledronic acid, and gonadotropin-releasing hormone (GnRH) analog. Platinum improves the pathological complete response (PCR) rate of patients treated with neoadjuvant chemotherapy (NACT), the objective remission rate (ORR) and overall survival (OS) in patients with metastatic triple-negative breast cancer. Capecitabine improves disease-free survival (DFS) and OS in patients treated with adjuvant CT. Bevacizumab was added to NACT to improve the PCR rate in patients. Immunotherapy improves the PCR rate in patients treated with NACT. The improvement in PCR rate in patients with high Ki67 expression treated with neoadjuvant therapy is highly suggestive. Other interventions had suggestive or weak evidence.

Conclusion

Among the strategies for treating TNBC, platinum, bevacizumab, and immunotherapy can lead to better PCR rates as part of a NACT regimen. Capecitabine as adjuvant CT and platinum in the treatment of metastatic TNBC can benefit patients’ survival. However, the effectiveness of other interventions for TNBC is not yet clear. Further research is needed in the future to obtain more reliable clinical evidence.

Prognostic Factors and Models for Elderly (≥70 Years Old) Primary Operable Triple-Negative Breast Cancer: Analysis From the National Cancer Database

BACKGROUND

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer. In the elderly (≥70 years old) primary operable (T_1-3N_0-1M₀) TNBC, individualized treatment modalities for this population are pivotal and important, but limited studies are explored.

METHODS

The clinicopathological features of elderly primary operable TNBC patients were retrospectively selected from the Surveillance, Epidemiology, and End Results (SEER) database between January 2010 and December 2015. Kaplan-Meier curves were used to show the survival patterns in the different subgroups. Multivariate Cox analysis was used to identify independent risk factors in the 3-, 5-, and 7- year overall survival (OS) and cancer-specific survival (CSS) in this subpopulation. The predictive model was further developed and validated for clinical use.

RESULT

Between 2010 and 2015 years, a total of 4,761 elderly primary operable TNBC patients were enrolled for the study, with a mean age of 76 years and a median follow-up of 56 months. The multivariate Cox analysis showed that age (increased per year: hazard ratio (HR) = 1.05), race (Asian/Pacific Islander and American Indian/Alaska Native, HR = 0.73), differentiation grade (grade II: HR = 2.01; grade III/IV: HR = 2.67), larger tumor size (T_1c: HR = 1.83; T₂: HR = 2.78; T₃: HR = 4.93), positive N stage (N_1mi: HR = 1.60; N₁: HR = 1.54), receiving radiation therapy (HR = 0.66), and receiving adjuvant chemotherapy (HR = 0.61) were the independent prognostic factors for OS, and a similar prognostic pattern was also determined in CSS. Besides, two nomograms for predicting the 3-, 5-, and 7-year OS and CSS in this population were developed with a favorable concordance index of 0.716 and 0.746, respectively.

CONCLUSION

The results highlight that both radiation and adjuvant chemotherapy are significantly associated with favorable long-term OS and CSS probability in elderly primary operable TNBC patients. Based on the determined independent prognostic factors, the novel nomograms could assist the oncologists to make individualized clinical decisions for the subpopulation at different risks.

THOC2 and THOC5 Regulate Stemness and Radioresistance in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer. Radioresistance and stemness are substantial obstacles to TNBC treatment. The THO complex (THOC) is a subunit of the TRanscription-EXport complex that functions in the coupling of transcription to nascent RNA splicing, elongation, and export. However, its role in regulating TNBC therapeutic resistance is not reported yet. In this study, the authors demonstrate that cancer stem cells are enriched in radioresistant TNBC cells and describe the role of the THOC in regulating TNBC radioresistance and stemness. The authors find that THOC2 and THOC5 are upregulated in radioresistant TNBC cells and associated with a poor prognosis in TNBC patients. Further investigation reveals that THOC2 promotes the stem-like properties and radioresistance of TNBC cells in a THOC5-dependent manner by facilitating the release of sex-determining region Y (SRY)-box transcription factor 2 (SOX2) and homeobox transcription factor (NANOG) transcripts from the nucleus. Silencing THOC2 or THOC5 expression decreases the protein expression of SOX2 and NANOG, depletes the stem-like properties, and causes radiosensitization in these TNBC cells. Moreover, THOC2 or THOC5 depletion blocks the xenograft tumorigenesis and growth of radioresistant TNBC in vivo. These findings uncover the novel correlations of THOC with TNBC stemness and therapeutic resistance, proposing alternative therapeutic strategies against relapsed TNBC.

Over-expression of SRD5A3 and its prognostic significance in breast cancer

Objective

The study aimed to compare the Steroid 5 alpha-reductase 3 (SRD5A3) expression levels in breast cancer (BC) and normal tissues, to investigate the prognostic value of SRD5A3 mRNA expression in BC patients and to identify the SRD5A3-related signaling pathways using bioinformatics approaches.

Methods

We evaluated the expression levels of SRD5A3 and survival data in BC patients using different bioinformatic databases. Further, Cox regression analysis was conducted to predict the independent prognostic factors for BC. Moreover, the association of SRD5A3 with clinicopathological factors was measured through LinkedOmics database. And the potential role of SRD5A3 was determined by Gene Ontology and KEGG pathway enrichment analysis. Finally, protein network of SRD5A3 was constructed and genetic alterations were analyzed.

Results

Bioinformatic data indicated that both mRNA and protein expression levels of SRD5A3 were higher in BC group than those in the normal group (P < 0.05). Besides, BC patients with higher SRD5A3 mRNA expression levels had a lower overall survival (all P < 0.05). Cox regression analysis further demonstrated the independent prognostic value of SRD5A3 in BC (P = 0.015). SRD5A3 mRNA expression was significantly associated with N stage (P < 0.001), age (P < 0.05), and histologic subtype (P < 0.001) but had no significant relationship with other clinical characteristics (all P > 0.05). Moreover, the functional enrichment analysis revealed that the SRD5A3 was involved in metabolism-related pathways (all P < 0.05).

Conclusions

SRD5A3 was highly expressed in BC tissues and high SRD5A3 expression was related to poorer prognosis. SRD5A3 serves as an oncogene and might function as a potential biomarker for prognosis and a therapeutic target for BC.

Breast-Gynaecological & Immuno-Oncology International Cancer Conference (BGICC) Consensus and Recommendations for the Management of Triple-Negative Breast Cancer

Background: The management of patients with triple-negative breast cancer (TNBC) is challenging with several controversies and unmet needs. During the 12th Breast-Gynaecological & Immuno-oncology International Cancer Conference (BGICC) Egypt, 2020, a panel of 35 breast cancer experts from 13 countries voted on consensus guidelines for the clinical management of TNBC. The consensus was subsequently updated based on the most recent data evolved lately. Methods: A consensus conference approach adapted from the American Society of Clinical Oncology (ASCO) was utilized. The panellists voted anonymously on each question, and a consensus was achieved when ≥75% of voters selected an answer. The final consensus was later circulated to the panellists for critical revision of important intellectual content. Results and conclusion: These recommendations represent the available clinical evidence and expert opinion when evidence is scarce. The percentage of the consensus votes, levels of evidence and grades of recommendation are presented for each statement. The consensus covered all the aspects of TNBC management starting from defining TNBC to the management of metastatic disease and highlighted the rapidly evolving landscape in this field. Consensus was reached in 70% of the statements (35/50). In addition, areas of warranted research were identified to guide future prospective clinical trials.

Appraising the quality of meta-analysis for breast cancer treatment in the adjuvant setting: A systematic review

INTRODUCTION

Breast cancer is the tumor with highest incidence in women worldwide and adjuvant treatment is extremely important to achieve disease control. Given the relevance of systematic reviews, their rigor should be warranted to avoid biased conclusions. Our objective was to investigate the methodological quality of meta-analysis of early breast cancer adjuvant treatment.

MATERIAL AND METHODS

Comprehensive searches were performed using electronic databases from 1/1/2007 to 11/12/2018. All studies identified as a systematic review with meta-analysis investigating the efficacy of breast cancer adjuvant treatments were included. Two reviewers independently assessed titles and abstracts, then full-texts for eligibility. Quality was assessed using the Assessing the Methodological Quality of Systematic Reviews (AMSTAR) version 2 tool.

RESULTS

Of 950 citations retrieved, 66 studies (7.0%) were deemed eligible. Methodological quality was highly variable, median AMSTAR score 8.5 (IQR 7-9.5) and range 0-16. There was a weak positive correlation between journal impact factor and AMSTAR score (r = 0.17) and citation rate and AMSTAR score (r = 0.16). Cochrane Systematic Reviews were of higher quality than reviews from other journals. Overall confidence was critically low for 61 (92.4%) studies, and the least well-reported domains were the statement of conflict of interest and funding source for the included studies (4.6%), the report of a pre-defined study protocol (15.2%), and the description of details of excluded studies (6.1%).

CONCLUSIONS

Our findings reinforce concerns about the design, conduction and interpretation of meta-analysis in current literature. Methodological quality should be carefully considered and journal editors, decision makers and readers in general, must follow a critical approach to this studies.

The Effect of Postmastectomy Radiotherapy on Breast Cancer Patients After Neoadjuvant Chemotherapy by Molecular Subtype

BACKGROUND

The effect of postmastectomy radiotherapy (PMRT) on patient outcomes after neoadjuvant chemotherapy (NAC) remains controversial. We aimed to establish a model to identify the subsets benefiting from PMRT and to examine the effect of PMRT according to molecular subtype.

PATIENTS AND METHODS

We retrospectively analyzed 1118 cT1-4cN0-3M0 breast cancer patients treated with NAC and mastectomy. A nomogram predicting locoregional recurrence (LRR) was established based on 418 unirradiated patients, and X-tile analysis was performed to divide the patients into two risk groups. The effect of PMRT on LRR, distant recurrence (DR), and breast cancer mortality (BCM) was estimated for patients with different molecular subtypes in two risk groups.

RESULTS

A nomogram predicting LRR was developed using six factors: histologic classification, lymphovascular invasion, ypT stage, ypN stage, estrogen receptor status, and Ki-67 expression. Our study found that PMRT correlated with lower 5-year LRR, DR, and BCM rates for the high-risk group; however, no significant improvement in these endpoints was observed in the low-risk group. Among patients with high risk, subgroup analysis showed that LRR control was improved after PMRT for the human epidermal growth factor receptor 2 (HER2)-negative/hormone receptor (HR)-positive (HER2-/HR+), HER2-positive (HER2+)/HR+, and HER2-/HR-negative (HR-) subtypes, with hazard ratios of 0.113 (95% confidence [CI] 0.034-0.379; p < 0.001), 0.159 (95% CI 0.038-0.671; p = 0.017), and 0.243 (95% CI 0.088-0.676; p = 0.007), respectively, but not for the HER2+/HR- subtype (p = 0.468).

CONCLUSIONS

We built a nomogram showing favorable risk quantification and patient stratification. Patients in the high-risk group benefited from PMRT, but patients in the low-risk group did not. PMRT may show different benefits for each molecular subtype.

Dual blockade of CD47 and HER2 eliminates radioresistant breast cancer cells

Although the efficacy of cancer radiotherapy (RT) can be enhanced by targeted immunotherapy, the immunosuppressive factors induced by radiation on tumor cells remain to be identified. Here, we report that CD47-mediated anti-phagocytosis is concurrently upregulated with HER2 in radioresistant breast cancer (BC) cells and RT-treated mouse syngeneic BC. Co-expression of both receptors is more frequently detected in recurrent BC patients with poor prognosis. CD47 is upregulated preferentially in HER2-expressing cells, and blocking CD47 or HER2 reduces both receptors with diminished clonogenicity and augmented phagocytosis. CRISPR-mediated CD47 and HER2 dual knockouts not only inhibit clonogenicity but also enhance macrophage-mediated attack. Dual antibody of both receptors synergizes with RT in control of syngeneic mouse breast tumor. These results provide the evidence that aggressive behavior of radioresistant BC is caused by CD47-mediated anti-phagocytosis conjugated with HER2-prompted proliferation. Dual blockade of CD47 and HER2 is suggested to eliminate resistant cancer cells in BC radiotherapy.

Triple-negative breast cancer in Peru: 2000 patients and 15 years of experience

Background

Epidemiological studies commonly identify the clinical characteristics and survival outcomes of patients with breast cancer at five years. Our study aims to describe the sociodemographic, clinicopathological characteristics and determine the long-term event-free survival (EFS) and overall survival (OS) of a Peruvian population with triple-negative breast cancer.

Methods

We reviewed the medical records of new cases treated at a single institution in the period 2000–2014. The survival analysis included patients with stages I-IV. Survival estimates at 10 years were calculated with the Kaplan-Meier method and compared with the Log-rank test. We further used multivariate Cox regression analysis to calculate prognostic factors of recurrence and mortality.

Results

Among the 2007 patients included, the median age at diagnosis was 49 years (19–95 years). Most patients presented histologic grade III (68.7%), tumor stage II (34.2%), and III (51.0%) at diagnosis. Local and distant relapse was present in 31.9 and 51.4% of the patients, respectively. The most frequent sites of metastasis were the lungs (14.5%), followed by bone (9.7%), brain (9.6%), and liver (7.9%). The median follow-up was 153 months. At 3, 5, and 10 years, the EFS of the population was 55%, 49%, and 41%, respectively, while the OS was 64%, 56%, and 47%, respectively. Moreover, an N3 lymph node status was the most important prognostic factor for both disease relapse (HR: 2.54, 95% CI: 2.05–3.15) and mortality (HR: 2.51, 95% CI: 2.01–3.14) at ten years. An older age and higher T staging were associated with a worse OS, while patients who received radiotherapy and adjuvant chemotherapy had better survival rates.

Conclusion

The sociodemographic features of Peruvian patients with TNBC are similar to those of other populations. However, our population was diagnosed at more advanced clinical stages, and thus, EFS and OS were lower than international reports while prognostic factors were similar to previous studies.

Lignin-graft-PLGA drug-delivery system improves efficacy of MEK1/2 inhibitors in triple-negative breast cancer cell line

Aim: Few targeted therapies are available for triple-negative breast cancer (TNBC) patients. Here, we propose a novel alkaline-lignin-conjugated-poly(lactic- co-glycolic acid) (L-PLGA) nanoparticle drug delivery system to improve the efficacy of targeted therapies. Materials & methods: L-PLGA nanoparticles (NPs) loaded with the MEK1/2 inhibitor GDC-0623 were characterized, tested in vitro on MDA-MB-231 TNBC cell line and compared with loaded PLGA NPs. Results: Loaded L-PLGA NPs were less than half the size of PLGA NPs, had slower drug release and improved the efficacy of GDC-0623 when tested in vitro. We demonstrated that GDC-0623 reversed epithelial-to-mesenchymal transition in TNBC. Conclusion: Our findings indicate that L-PLGA NPs are superior to PLGA NPs in delivering GDC-0623 to cancer cells for improved efficacy in vitro.

Synergy between Non-Thermal Plasma with Radiation Therapy and Olaparib in a Panel of Breast Cancer Cell Lines

Cancer therapy has evolved to a more targeted approach and often involves drug combinations to achieve better response rates. Non-thermal plasma (NTP), a technology rapidly expanding its application in the medical field, is a near room temperature ionized gas capable of producing reactive species, and can induce cancer cell death both in vitro and in vivo. Here, we used proliferation assay to characterize the plasma sensitivity of fourteen breast cancer cell lines. These assays showed that all tested cell lines were sensitive to NTP. In addition, a good correlation was found comparing cell sensitivity to NTP and radiation therapy (RT), where cells that were sensitive to RT were also sensitive to plasma. Moreover, in some breast cancer cell lines, NTP and RT have a synergistic effect. Adding a dose of PARP-inhibitor olaparib to NTP treatment always increases the efficacy of the treatment. Olaparib also exhibits a synergistic effect with NTP, especially in triple negative breast cancer cells. Results presented here help elucidate the position of plasma use as a potential breast cancer treatment.

Preliminary study of contrast-enhanced ultrasound in combination with blue dye vs. indocyanine green fluorescence, in combination with blue dye for sentinel lymph node biopsy in breast cancer

Background

This preliminary study aimed to examine the feasibility of sentinel lymph node biopsy (SLNB) using contrast-enhanced ultrasound (CEUS) vs. indocyanine green fluorescence (ICG), combined with blue dye in patients with breast cancer.

Methods

This was a retrospective study of consecutive female patients with invasive stage I-III (based on pre-operative physical examination and imaging) primary breast cancer at the Peking Union Medical College Hospital between 01/2013 and 01/2015 who underwent preoperative SLNB by ICG + blue dye or CEUS + blue dye. The numbers of detected SLNs, detection rates, and recurrence-free survival (RFS) rates were compared between the two groups.

Results

A total of 443 patients were included. The detection rates of SLNs in the CEUS + blue dye and ICG + blue dye groups were 98.4 and 98.1%, respectively (P = 0.814). The average numbers of SLNs detected per patient showed no significant difference between the two groups (3.06 ± 1.33 and 3.12 ± 1.31 in the CEUS + blue dye and ICG + blue dye groups, respectively; P = 0.659). After a median follow-up of 46 months, five patients in the CEUS + blue dye group and 15 in the ICG + blue dye group had recurrence. RFS rates showed no significant difference (P = 0.55).

Conclusion

This preliminary study suggests that CEUS + blue dye and ICG + blue dye are both feasible for SLN detection in breast cancer.

T1-2N0M0 Triple-Negative Breast Cancer Treated With Breast-Conserving Therapy Has Better Survival Compared to Mastectomy: A SEER Population-Based Retrospective Analysis

BACKGROUND

For early-stage breast cancer, the two current mainstay treatments are breast-conserving therapy (BCT; lumpectomy followed by radiotherapy [RT] and BCT) and mastectomy. Generally, triple-negative breast cancer (TNBC) is more aggressive compared to hormone receptor-positive breast cancer. We sought to investigate the effect of BCT compared to mastectomy on overall survival (OS) and breast cancer-specific survival (BCSS) in T1-2N0M0 TNBC.

PATIENTS AND METHODS

A population-based retrospective analysis was performed using the Surveillance, Epidemiology, and End Results (SEER) database. Patients included in the analysis were divided into 3 groups according to surgical modality and RT: BCT, mastectomy alone, and mastectomy with RT. The survival end points were OS and BCSS, and survival analysis was performed by the Kaplan-Meier method and the log-rank test among treatment types.

RESULTS

A total of 14,910 female subjects with T1-2N0M0 TNBC diagnosed between 2010 and 2014 were included. A total of 7381 patients had BCT; 6967 had mastectomy alone, and 562 had mastectomy with RT. Patients treated with BCT had better OS (log-rank P < .05) and BCSS (log-rank P < .05) than those receiving mastectomy with or without RT. The 5-year OS was 88.6% for BCT, 83.0% for mastectomy alone, and 79.6% for mastectomy with RT. The 5-year BCSS was 94.3% for BCT, 93.3% for mastectomy alone, and 83.7% for mastectomy with RT.

CONCLUSION

In patients with T1-2N0M0 TNBC, BCT was associated with superior OS and BCSS compared to mastectomy with or without RT. After mastectomy, there was no evidence of survival benefit of RT.

Radiotherapy after surgery has significant survival benefits for patients with triple-negative breast cancer

Objectives

The value of adjuvant radiotherapy for triple‐negative breast cancer (TNBC) has been controversial recently. This study aims to clarify the influence of radiotherapy on the survival of TNBC patients after surgery based on a large population analysis.

Methods

The Surveillance, Epidemiology, and End Results (SEER) database was exploited to select eligible patients from 2010 to 2014. The categorical variables were examined by chi‐square tests. Breast cancer‐specific survival (BCSS) and overall survival (OS) were compared among patients who received or not received adjuvant radiotherapy after surgery by Kaplan‐Meier method with log‐rank test. Univariate and multivariate survival analysis of BCSS and OS were performed using the Cox proportional hazard model.

Results

Totally 22 802 patients were enrolled in this study, of which 10 905 patients received radiotherapy after surgery while 11 897 patients did not receive radiotherapy. Compared with those patients who did not receive radiotherapy, the radiation group had a larger proportion of tumor size <2.0 cm (45.8% vs 38.8%) and chemotherapy (82.5% vs 67.4%). The Kaplan‐Meier plots displayed that patients in the radiation group had better survival than the no radiation group in both BCSS and OS (P < 0.001, respectively). In univariate Cox analysis of BCSS, age 40‐60, married status, white and other race, chemotherapy, radiation, and surgery were associated with better survival (HR < 1, P < 0.05). Specifically, patients who received radiotherapy exhibited better BCSS (HR = 0.52, 95% CI = 0.48‐0.57, P < 0.001). After adjusting for confounding factors by multivariable Cox regression analysis, receipt of radiotherapy was still associated with improved BCSS (HR = 0.79, 95% CI = 0.72‐0.87, P < 0.001). Survival analysis of OS produced similar results. Generally, these data indicate that radiotherapy after surgery has significant survival benefits for the TNBC patients.

Conclusions

This study has confirmed the survival advantage of adjuvant radiotherapy for the TNBC patients. These findings may optimize the current individualized treatment decisions for this patient population.

Assessing the prognostic factors, survival, and recurrence incidence of triple negative breast cancer patients, a single center study in Iran

Background

Breast cancer is the second leading cause of death due to cancer in women. Triple negative breast cancer (TNBC) is a subgroup with unique behavior. There is a controversy in organ involvement in metastasis. In this study, we planned to define the prognostic factors, survival, and recurrence incidence of patients.

Materials and method

Among the 583 patients with breast mass referred to hematology and oncology clinic in Shariati hospital, Tehran, Iran from March 2005 to March 2015, fifty four patients entered the survival analysis whom we followed for two years until March 2017. Overall survival (OS) and disease-free survival (DFS) and Cumulative recurrence incidences (RI) were estimated. Univariate and multivariate Cox proportional hazards regression was performed to assess risk factors in predicting OS and DFS.

Results

Median follow up for the patients was 5.00 years. The five-year OS, DFS and RI were 86.13% (95% CI (71.42–93.59), 63.09% (95% CI (47.04–75.49) and 32.15% (95% CI (19.52–47.43) respectively. Among the factors studied OS, DFS and RI differed significantly only between patients with and without nodal involvement (P = 0.004, P = 0.003, and P = 0.02 respectively). On the other hand, based on the univariate modeling, patients with nodal involvement had a higher risk of breast cancer-specific death (HR: 17.99, P = 0.004). Furthermore, patients with nodal involvement had a higher risk of breast cancer-specific death or recurrence (HR = 5.64, P = 0.008). In Multivariate model, just the nodal involvement significantly changed the hazard for OS (HR = 23.91, P = 0.001). As the nodal involvement was the only significant risk factor at the 0.2 level of significance, we can consider the hazard ratio of lymph node positivity in DFS univariate models as adjusted hazard.

Conclusion

The only factor with significant effect on OS, DFS and RI was nodal involvement in the pathology report.

Breast-conserving surgery versus mastectomy in young women with breast cancer in Asian settings

Background

Mastectomy rates among women with early breast cancer in Asia have traditionally been high. This study assessed trends in the surgical management of young women with early‐stage breast cancer in Asian settings. Survival in women treated with breast‐conserving surgery (BCS; lumpectomy with adjuvant radiotherapy) and those undergoing mastectomy was compared.

Methods

Young women (aged less than 50 years) newly diagnosed with stage I or II (T1–2 N0–1 M0) breast cancer in four hospitals in Malaysia, Singapore and Hong Kong in 1990–2012 were included. Overall survival (OS) was compared for patients treated by BCS and those who had a mastectomy. Propensity score analysis was used to account for differences in demographic, tumour and treatment characteristics between the groups.

Results

Some 63·5 per cent of 3536 women underwent mastectomy. Over a 15‐year period, only a modest increase in rates of BCS was observed. Although BCS was significantly associated with favourable prognostic features, OS was not significantly different for BCS and mastectomy; the 5‐year OS rate was 94·9 (95 per cent c.i. 93·5 to 96·3) and 92·9 (91·7 to 94·1) per cent respectively. Inferences remained unchanged following propensity score analysis (hazard ratio for BCS versus mastectomy: 0·81, 95 per cent c.i. 0·64 to 1·03).

Conclusion

The prevalence of young women with breast cancer treated by mastectomy remains high in Asian countries. Patients treated with BCS appear to survive as well as those undergoing mastectomy.

Radiation exposure triggers the progression of triple negative breast cancer via stabilizing ZEB1

Our present study confirmed radiation can promote the in vitro migration and invasion of triple negative breast cancer (TNBC) cells and increase the expression of epithelial-mesenchymal transition (EMT) related transcription factor ZEB1, while had no effect on Snail, Slug or Twist. Knockdown of ZEB1 attenuated radiation induced cell migration and invasion, suggesting that ZEB1 is essential for radiation induced progression of TNBC. Radiation increased the protein stability of ZEB1, while had no effect on its mRNA expression. Particularly, the upregulation of ATM, which can phosphorylate and stabilize ZEB1, was involved in radiation induced upregulation of ZEB1. Collectively, we found that radiation can promote the migration, invasion and EMT of TNBC cells through stabilization of ZEB1 via ATM signals.

Inhibition of basal-like breast cancer growth by FTY720 in combination with epidermal growth factor receptor kinase blockade

BACKGROUND

New molecular targets are needed for women with triple-negative breast cancer (TNBC). This pre-clinical study investigated the combination of the EGFR inhibitor gefitinib with the sphingosine kinase (SphK) inhibitor FTY720 (Fingolimod), aiming to block tumorigenic signaling downstream of IGFBP-3, which is abundantly expressed in basal-like TNBC.

METHODS

In studies of breast cancer cell growth in culture, proliferation was monitored by IncuCyte live-cell imaging, and protein abundance was determined by western blotting. In vivo studies of mammary tumor growth used two models: orthotopic xenograft tumors derived from three basal-like TNBC cell lines, grown in immune-deficient mice, and syngeneic murine 4T1 tumors grown in immune-competent mice. Protein abundance in tumor tissue was assessed by immunohistochemistry.

RESULTS

Quantitated by live-cell imaging, the inhibitor combination showed synergistic cytostatic activity in basal-like cell lines across several TNBC molecular subtypes, the synergy being decreased by IGFBP-3 downregulation. Suppression of the tumorigenic mediator CD44 by gefitinib was potentiated by FTY720, consistent with CD44 involvement in the targeted pathway. In MDA-MB-468 and HCC1806 orthotopic TNBC xenograft tumors in nude mice, the drug combination inhibited tumor growth and prolonged mouse survival, although this effect was not significant for the gefitinib-resistant cell line HCC70. Combination treatment of murine 4T1 TNBC tumors in syngeneic BALB/c mice was more effective in immune-competent than immune-deficient (nude) mice, and a relative loss of tumor CD3 (T-cell) immunoreactivity caused by FTY720 treatment alone was alleviated by the drug combination, suggesting that, even at an FTY720 dose causing relative lymphopenia, the combination is still effective in an immune-competent setting. Immunohistochemistry of xenograft tumors showed significant enhancement of caspase-3 cleavage and suppression of Ki67 and phospho-EGFR by the drug combination, but SphK1 downregulation occurred only in MDA-MB-468 tumors, so is unlikely to be integral to treatment efficacy.

CONCLUSIONS

Our data indicate that targeting IGFBP-3-dependent signaling pathways through gefitinib-FTY720 co-therapy may be effective in many basal-like breast cancers, and suggest tissue IGFBP-3 and CD44 measurement as potential biomarkers of treatment efficacy.

FSIP1 binds HER2 directly to regulate breast cancer growth and invasiveness

Fibrous sheath interacting protein 1 (FSIP1), a spermatogenesis-related testicular antigen, is expressed in abundance in breast cancers, particularly in those overexpressing human epidermal growth factor receptor 2 (HER2); however, little is known about its role in regulating the growth and metastasis of breast cancer cells. We and others have shown previously that FSIP1 expression in breast cancer correlates positively with HER2-positivity, recurrence, and metastases and negatively with survival. Here, using coimmunoprecipitation and microscale thermophoresis, we find that FSIP1 binds to the intracellular domain of HER2 directly. We further show that shRNA-induced FSIP1 knockdown in SKBR3 and MCF-7 breast cancer cells inhibits proliferation, stimulates apoptosis, attenuates epithelial-mesenchymal transition, and impairs migration and invasiveness. Consistent with reduced proliferation and enhanced apoptosis, xenotransplantation of SKBR3 cells stably transfected with sh-FSIP1 into nu/nu mice results in reduced tumor volumes compared with sh-NC transplants. Furthermore, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) mapping using sh-FSIP1 gene signature yielded associations with extracellular matrix protein pathways, and a reduction in SNAI2 protein expression was confirmed on Western blot analysis. Complementarily, interrogation of the Connectivity Map using the same gene signature yielded, as top hits, chemicals known to inhibit epithelial-mesenchymal transition, including rapamycin, 17-N-allylamino-17-demethoxygeldanamycin, and LY294002. These compounds phenocopy the effects of sh-FSIP1 on SKBR3 cell viability. Thus, FSIP1 suppression limits oncogenesis and invasiveness in breast cancer cells and, considering its absence in most other tissues, including normal breast, may become a potential target for breast cancer therapy.