Adjuvant chemotherapy for small, lymph node-negative, triple-negative breast cancer: A single-center study and a meta-analysis of the published literature

Benefit of adjuvant chemotherapy for T1cN0M0 and selected T1bN0M0 triple-negative breast cancer: a nationwide cancer registry-based study

BACKGROUND

The efficacy of adjuvant chemotherapy for T1N0M0 triple-negative breast cancer (TNBC) has not been clearly elucidated. Thus, we aimed to evaluate the efficacy of adjuvant chemotherapy for patients with T1a-cN0M0 TNBC.

PATIENTS AND METHODS

Patients newly diagnosed with TNBC between 2011 and 2015 were identified and followed up until the end of 2020 using the Taiwan Cancer Registry. Univariate and multivariate Cox proportional hazards regression analyses were performed to compare the recurrence-free survival (RFS) and OS between patients who received and those who did not receive adjuvant chemotherapy.

RESULTS

Of the 62 483 patients registered during 2011-2015, 1074 patients with T1N0M0 TNBC (T1a, n = 103; T1b, n = 167; and T1c, n = 804) who underwent definitive breast surgery were included. Overall, 850 (79%) patients received adjuvant chemotherapy; these comprised 24.3%, 67.7%, and 88.6% of the patients with T1a, T1b, and T1c disease, respectively. Over a median follow-up of 7.18 years, a significant RFS and OS benefit from adjuvant chemotherapy was observed in the T1c subgroup but not in the T1a and T1b subgroups. However, subgroup analysis of T1b disease indicated that adjuvant chemotherapy yielded an OS benefit to patients with histological grade III disease (adjusted hazard ratio = 0.08, 95% CI, 0.01-0.77; P = .03).

CONCLUSIONS

Adjuvant chemotherapy improved the RFS and OS in patients with T1cN0M0 TNBC and improved the OS in patients with histological grade III T1bN0M0 disease. Our study advocates for the utilization of adjuvant chemotherapy in patients diagnosed with T1cN0M0 and histological grade III T1bN0M0 TNBC.

Prognostic value of adjuvant chemotherapy for hormone receptor-negative T1a and T1bN0M0 breast cancer patients

The benefit of adjuvant chemotherapy (CT) for hormone receptor-negative T1a and T1bN0M0 breast cancer remains uncertain. Our study was to explore prognostic value and identify candidates of adjuvant CT for these patients. The data of hormone receptor-negative T1a and T1bN0M0 breast cancer patients were extracted from the Surveillance, Epidemiology, and End Results (SEER) database from 2010 to 2015. All patients were divided into two groups according to the history of adjuvant CT namely the CT group and the no CT (No CT) group. Univariate and multivariate Cox regression analysis were utilized to identify factors linked with cancer specific survival (CSS) and overall survival (OS) for the patients. Kaplan-Meier method was employed to determine survival benefit of adjuvant CT. A total of 3889 patients were included. After propensity score-matching, 1217 patients were assigned to the CT group and 1217 patients were assigned to the No CT group respectively. Based on multivariate Cox regression analysis of OS, older age, single, T1b stage, triple-negative tumor and absence of adjuvant CT were identified as risk factors related to OS. Besides, multivariable Cox regression analysis of CSS showed significant association between grade III+IV, T1b stage, triple-negative tumor and absence of adjuvant CT and CSS. The results from Kaplan-Meier curves revealed that adjuvant CT could bring OS benefit for these patients with more than two risk factors and could improve CSS for the patients with more than one risk factor. Our study supports the implementation of individualized strategies for hormone receptor-negative T1a and T1bN0M0 breast cancer patients. Adjuvant CT was recommended for potential beneficial patients after undertaking a risk-benefit discussion.

Does T1c-2N0-1M0 triple negative breast cancer derive a benefit from neoadjuvant chemotherapy?

OBJECTIVES

Although neoadjuvant chemotherapy (NCT) is a standard approach for operable triple negative breast cancer (TNBC), the potential risks brought by it should also be noticed. Is the expanding indication of NCT to T1cN0M0 population appropriate? We conducted an investigation to compare the long-term survival of small tumor TNBC between NCT and adjuvant chemotherapy (ACT).

METHODS

For this propensity-matched analysis, we used data from Surveillance, Epidemiology, and End Results (SEER) database. We enrolled 1183 cases with NCT and 2550 cases with ACT who are AJCC clinical T1c-T2 N0-N1, diagnosed with invasive triple-negative breast cancer, from 2016 to 2017. The propensity score matching was utilized to minimize baseline characteristics bias. Hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated by the Cox proportional hazard regression model.

RESULTS

Compared with patients receiving ACT, patients with NCT in this study presented a higher proportion of younger age, T2 stage, N1 stage, and underwent more mastectomy. Multivariate analysis in matched patients showed that NCT had no significant survival benefit compared with ACT in T1c-2N0-1M0 TNBC patients. Stratified analyses by T stage and N stage demonstrated NCT mainly presented a survival advantage in patients with N1 stage. Further investigation found that NCT didn't improve BCSS (HR, 0.472; 95% CI 0.135-1.647; P = 0.239) and OS (HR, 0.392; 95% CI 0.147-1.047; P = 0.062) for patients with T1cN0M0 TNBC; however, it was associated with improved OS (HR, 1.951; 95% CI 1.003-3.797; P = 0.049) only for patients with T2N1M0 TNBC.

CONCLUSIONS

In this study, we did not find any profit brought by NCT in the stage I and stage IIa cohorts, but even more unfavorable outcomes appeared in the T1cN0M0 cohort. Therefore, whether the candidates of NCT should be extended to T1cN0M0 still need to be cautious.

Neoadjuvant Therapy: Current Landscape and Future Horizons for ER-Positive/HER2-Negative and Triple-Negative Early Breast Cancer

OPINION STATEMENT

Navigating the complex landscape of breast cancer treatment involves distinct strategies for luminal and triple-negative subtypes. While neoadjuvant chemotherapy historically dominates the approach for aggressive triple-negative tumors, recent evidence highlights the transformative impact of immunotherapy, alongside chemotherapy, in reshaping treatment paradigms. In luminal cancers, endocrine therapy, notably aromatase inhibitors, demonstrates promising outcomes in postmenopausal patients with low-grade luminal A tumors. However, integrating targeted therapies like CDK4/6 inhibitors in neoadjuvant setting remains inconclusive. Identifying predictive factors for treatment response, especially in luminal tumors, poses a challenge, emphasizing the necessity for ongoing research. A multidisciplinary approach, tailored to individual patient profiles, is crucial for maximizing efficacy while minimizing toxicity. As we strive to optimize breast cancer management, a comprehensive understanding of the distinct characteristics and treatment implications of luminal and triple-negative subtypes, including the transformative role of immunotherapy, is essential for informed decision-making and personalized care.

Personalized chemotherapy selection for patients with triple-negative breast cancer using deep learning

Background

Potential uncertainties and overtreatment exist in adjuvant chemotherapy for triple-negative breast cancer (TNBC) patients.

Objectives

This study aims to explore the performance of deep learning (DL) models in personalized chemotherapy selection and quantify the impact of baseline characteristics on treatment efficacy.

Methods

Patients who received treatment recommended by models were compared to those who did not. Overall survival for treatment according to model recommendations was the primary outcome. To mitigate bias, inverse probability treatment weighting (IPTW) was employed. A mixed-effect multivariate linear regression was employed to visualize the influence of certain baseline features of patients on chemotherapy selection.

Results

A total of 10,070 female TNBC patients met the inclusion criteria. Treatment according to Self-Normalizing Balanced (SNB) individual treatment effect for survival data model recommendations was associated with a survival benefit (IPTW-adjusted hazard ratio: 0.53, 95% CI, 0.32-8.60; IPTW-adjusted risk difference: 12.90, 95% CI, 6.99-19.01; IPTW-adjusted the difference in restricted mean survival time: 5.54, 95% CI, 1.36-8.61), which surpassed other models and the National Comprehensive Cancer Network guidelines. No survival benefit for chemotherapy was seen for patients not recommended to receive this treatment. SNB predicted older patients with larger tumors and more positive lymph nodes are the optimal candidates for chemotherapy.

Conclusion

These findings suggest that the SNB model may identify patients with TNBC who could benefit from chemotherapy. This novel analytical approach may provide debiased individual survival information and treatment recommendations. Further research is required to validate these models in clinical settings with more features and outcome measurements.

Benefit of adjuvant chemotherapy in lymph node-negative, T1b and T1c triple-negative breast cancer

INTRODUCTION

Current guidelines recommendations regarding chemotherapy in small (T1b and T1c), node-negative triple-negative breast cancer (TNBC) differ due to lack of high-quality data. Our study aimed to assess the benefit of adjuvant chemotherapy in patients with T1bN0M0 and T1cN0M0 TNBC.

METHODS

We obtained data from the Surveillance, Epidemiology, and End Results database for patients with node-negative, T1b/T1c TNBC diagnosed between 2010 and 2020. Logistic regresion models assessed variables associated with chemotherapy administration. We evaluated the effect of chemotherapy on overall survival (OS) and breast cancer specific survival (BCSS) with Kaplan-Meier methods and Cox proportional hazards methods.

RESULTS

We included 11,510 patients: 3,388 with T1b and 8,122 with T1c TNBC. During a median follow-up of 66 months, 305 patients with T1b and 995 with T1c died. After adjusting for clinicopathological, demographic and treatment factors, adjuvant chemotherapy improved OS in T1b TNBC (HR, 0.52; 95% CI, 0.41-0.68 p < 0.001) but did not improve BCSS (HR, 0.70; 95% CI, 0.45-1.07; p = 0.10); the association between chemotherapy and BCSS was not statistically significant in any subgroup. In T1c TNBC, adjuvant chemotherapy improved OS (HR, 0.54; 95% CI, 0.47-0.62; p < 0.001) and BCSS (HR, 0.79; 95% CI, 0.63-0.99; p = 0.043); the benefit of chemotherapy in OS varied by age (Pinteraction=0.024); moreover, the benefit in BCSS was similar in all subgroups.

CONCLUSIONS

Our study results support the use of adjuvant chemotherapy in patients with node-negative, T1c TNBC. Patients with node-negative, T1b TNBC had excellent long-term outcomes; furthermore, chemotherapy was not associated with improved BCSS in these patients.

Assessment of Use and Impact of Chemotherapy in Lymph Node-Negative, T1a Triple-Negative Breast Cancer

BACKGROUND

Current treatment guidelines suggest considering adjuvant chemotherapy in high-risk patients with T1a, node-negative triple-negative breast cancer (TNBC); however, limited quality data support this statement. Our population-based study assessed the efficacy of adjuvant chemotherapy and factors associated with its administration in node-negative, T1a TNBC.

MATERIALS AND METHODS

We obtained data from the Surveillance, Epidemiology, and End Results database for patients with T1aN0 TNBC diagnosed between 2010 and 2019. We utilized the Kaplan-Meier method and Cox regression model to analyze the overall survival (OS) and breast cancer-specific survival (BCSS) in chemotherapy benefit. We performed stratified models to identify differences in OS and BCSS between those who received chemotherapy and those who did not across subgroups. Competing risk analysis was conducted to assess differences in risk of breast cancer death in patients with chemotherapy administration versus no chemotherapy. Additionally, propensity score matching was executed to assess survival analysis in a matched cohort.

RESULTS

We included 1739 patients with T1a TNBC. Patients who received chemotherapy were younger, had higher histological grade and ductal histology subtype, were more likely to be married and undergo mastectomy. Our study did not show improvement in OS (HR, 0.63; 95% CI, 0.35-1.13; P = .122) or BCSS (HR, 0.95; 95% CI, 0.37-2.43; P = .908) after chemotherapy use. We did not identify any subgroup of patients that may benefit from chemotherapy. Without chemotherapy, 8-year risk of breast cancer death is 2.75% for these patients.

CONCLUSION

Adjuvant chemotherapy is not associated with benefit on OS or BCSS in node-negative, T1a TNBC.

SEOM-GEICAM-SOLTI clinical guidelines for early-stage breast cancer (2022)

Breast cancer is the leading cause of cancer in women in Spain and its annual incidence is rapidly increasing. Thanks to the screening programs in place, nearly 90% of breast cancer cases are detected in early and potentially curable stages, despite the COVID-19 pandemic possibly having impacted these numbers (not yet quantified). In recent years, locoregional and systemic therapies are increasingly being directed by new diagnostic tools that have improved the balance between toxicity and clinical benefit. New therapeutic strategies, such as immunotherapy, targeted drugs, and antibody-drug conjugates have also improved outcomes in some patient subgroups. This clinical practice guideline is based on a systematic review of relevant studies and on the consensus of experts from GEICAM, SOLTI, and SEOM.

Clinical outcomes and prognostic factors in triple-negative invasive lobular carcinoma of the breast

PURPOSE

Triple-negative invasive lobular carcinoma (TN-ILC) of breast cancer is a rare disease and the clinical outcomes and prognostic factors are not well-defined.

METHODS

Women with stage I-III TN-ILC or triple-negative invasive ductal carcinoma (TN-IDC) of the breast undergoing mastectomy or breast-conserving surgery between 2010 and 2018 in the National Cancer Database were included. Kaplan-Meier curves and multivariate Cox proportional hazard regression were used to compare overall survival (OS) and evaluate prognostic factors. Multivariate logistic regression was performed to analyze the factors associated with pathological response to neoadjuvant chemotherapy.

RESULTS

The median age at diagnosis for women with TN-ILC was 67 years compared to 58 years in TN-IDC (p < 0.001). There was no significant difference in the OS between TN-ILC and TN-IDC in multivariate analysis (HR 0.96, p = 0.44). Black race and higher TNM stage were associated with worse OS, whereas receipt of chemotherapy or radiation was associated with better OS in TN-ILC. Among women with TN-ILC receiving neoadjuvant chemotherapy, the 5-year OS was 77.3% in women with a complete pathological response (pCR) compared to 39.8% in women without any response. The odds of achieving pCR following neoadjuvant chemotherapy were significantly lower in women with TN-ILC compared to TN-IDC (OR 0.53, p < 0.001).

CONCLUSION

Women with TN-ILC are older at diagnosis but have similar OS compared to TN-IDC after adjusting for tumor and demographic characteristics. Administration of chemotherapy was associated with improved OS in TN-ILC, but women with TN-ILC were less likely to achieve complete response to neoadjuvant therapy compared to TN-IDC.

Assessing the decision quality of artificial intelligence and oncologists of different experience in different regions in breast cancer treatment

Background

AI-based clinical decision support system (CDSS) has important prospects in overcoming the current informational challenges that cancer diseases faced, promoting the homogeneous development of standardized treatment among different geographical regions, and reforming the medical model. However, there are still a lack of relevant indicators to comprehensively assess its decision-making quality and clinical impact, which greatly limits the development of its clinical research and clinical application. This study aims to develop and application an assessment system that can comprehensively assess the decision-making quality and clinical impacts of physicians and CDSS.

Methods

Enrolled adjuvant treatment decision stage early breast cancer cases were randomly assigned to different decision-making physician panels (each panel consisted of three different seniority physicians in different grades hospitals), each physician made an independent "Initial Decision" and then reviewed the CDSS report online and made a "Final Decision". In addition, the CDSS and guideline expert groups independently review all cases and generate "CDSS Recommendations" and "Guideline Recommendations" respectively. Based on the design framework, a multi-level multi-indicator system including "Decision Concordance", "Calibrated Concordance", " Decision Concordance with High-level Physician", "Consensus Rate", "Decision Stability", "Guideline Conformity", and "Calibrated Conformity" were constructed.

Results

531 cases containing 2124 decision points were enrolled; 27 different seniority physicians from 10 different grades hospitals have generated 6372 decision opinions before and after referring to the "CDSS Recommendations" report respectively. Overall, the calibrated decision concordance was significantly higher for CDSS and provincial-senior physicians (80.9%) than other physicians. At the same time, CDSS has a higher " decision concordance with high-level physician" (76.3%-91.5%) than all physicians. The CDSS had significantly higher guideline conformity than all decision-making physicians and less internal variation, with an overall guideline conformity variance of 17.5% (97.5% vs. 80.0%), a standard deviation variance of 6.6% (1.3% vs. 7.9%), and a mean difference variance of 7.8% (1.5% vs. 9.3%). In addition, provincial-middle seniority physicians had the highest decision stability (54.5%). The overall consensus rate among physicians was 64.2%.

Conclusions

There are significant internal variation in the standardization treatment level of different seniority physicians in different geographical regions in the adjuvant treatment of early breast cancer. CDSS has a higher standardization treatment level than all physicians and has the potential to provide immediate decision support to physicians and have a positive impact on standardizing physicians' treatment behaviors.

Treatment of women with BRCA mutation

The cumulative risk for breast and ovarian cancer is high in BRCA1 or BRCA2 mutation carriers. The lifetime risk of breast cancer by the age of 80 years is respectively up to 72% and 69% in BRCA1 and BRCA2 mutation carriers. The risk of ovarian cancer is higher (44%) in BRCA1 than in BRCA2 (17%) mutation carriers. Breast and ovarian cancers tend to arise earlier in BRCA1 mutation carriers. Breast cancers in BRCA1 mutation carriers are more frequently (up to 70%) triple negative while the majority (up to 80%) of breast cancers in BRCA2 mutation carriers are hormone sensitive. Many issues remain to be resolved. In daily practice we are often confronted with patients having BRCA mutations classified as variants of unknown significance, who do have breast cancer personally or have a strong family history of breast cancer. On the other hand, 30-40% of mutation carriers will not develop breast cancer. Moreover, it is very difficult to predict the age at which cancer will arise. In a multidisciplinary setting we need to offer BRCA and other mutation carriers a wide range of information, advice and support.

Recent Advances in Optimizing Radiation Therapy Decisions in Early Invasive Breast Cancer

Adjuvant whole breast irradiation after breast-conserving surgery is a well-established treatment standard for early invasive breast cancer. Screening, early diagnosis, refinement in surgical techniques, the knowledge of new and specific molecular prognostic factors, and now the standard use of more effective neo/adjuvant systemic therapies have proven instrumental in reducing the rates of locoregional relapses. This underscores the need for reliably identifying women with such low-risk disease burdens in whom elimination of radiation from the treatment plan would not compromise oncological safety. This review summarizes the current evidence for radiation de-intensification strategies and details ongoing prospective clinical trials investigating the omission of adjuvant whole breast irradiation in molecularly defined low-risk breast cancers and related evidence supporting the potential for radiation de-escalation in HER2+ and triple-negative clinical subtypes. Furthermore, we discuss the current evidence for the de-escalation of regional nodal irradiation after neoadjuvant chemotherapy. Finally, we also detail the current knowledge of the clinical value of stromal tumor-infiltrating lymphocytes and liquid-based biomarkers as prognostic factors for locoregional relapse.

Adjuvant chemotherapy in patients with ER-negative/HER2-negative, T1abN0 breast cancer: a nationwide study

PURPOSE

The purpose of this study was to examine the effect of chemotherapy on invasive disease-free survival (iDFS) and overall survival (OS) in a nationwide cohort of patients with estrogen receptor (ER)-negative/human epidermal growth factor receptor 2 (HER2)-negative, T1abN0 breast cancer.

METHODS

Patients with ER-negative/HER2-negative, T1abN0 breast cancer registered in the Danish Breast Cancer Group database between 2007 and 2016 were identified. The effect of adjuvant chemotherapy on iDFS and OS was analyzed with Cox proportional hazards analysis.

RESULTS

In total, 296 patients were included in the statistical analyses. Of these, 235 (79.4%) received chemotherapy and 61 patients (20.6%) did not. Patients treated with chemotherapy were significantly younger, had a significantly higher proportion of grade 3 tumors, T1b tumors, and tumors of ductal subtype. With 7.7 years of median follow-up, treatment with chemotherapy was associated with a significant improvement in OS in the adjusted analysis, Hazard Ratio 0.35 (95% Confidence Interval (0.15-0.81), p = 0.02), chemotherapy vs. no chemotherapy. In the unadjusted analyses, patients with both T1a and T1b tumors had significantly improved OS with chemotherapy. At 5 years, OS was 100% vs. 94.4% and 93.8% vs. 81.3% for patients with T1a and T1b tumors, respectively, chemotherapy vs. no chemotherapy. With 4.9 years of median follow-up, iDFS was not significantly improved with chemotherapy.

CONCLUSION

Patients with ER-negative/HER2-negative, T1abN0 breast cancer had significantly improved OS when treated with chemotherapy. This improvement was significant in patients with both T1a and T1b tumors, respectively. The effect was, however, limited in patients with T1a tumors.

Are we overtreating stage I triple-negative breast cancer in Ontario? A population-based retrospective epidemiological analysis using the ICES database

Triple-negative breast cancer (TNBC) is associated with inferior outcomes. The use of adjuvant chemotherapy is the mainstay of treatment, and its efficacy was demonstrated to be correlated with tumor size. Different guidelines exist regarding chemotherapy in early-stage TNBC. This study uses ICES database to examine the outcomes of the use of adjuvant chemotherapy in stage I TNBC in Ontario stratified by tumor size. Records of TNBC patients diagnosed in 2012 to 2014 were collected from ICES database. Stage I patients were analyzed by tumor size: T1a (≤ 0.5 cm), T1b (> 0.5 cm and ≤ 1.0 cm), and T1c (> 1.0 cm and ≤ 2.0 cm). Kaplan-Meier curves, log-rank test statistic, and Cox's proportional hazard regression were used to compare differences in overall survival (OS) between chemotherapy and no-chemotherapy groups. Of 610 patients, 183 had tumor sizes ≤ 1 cm, representing stages T1aN0M0 and T1bN0M0, and 427 had tumors > 1 cm to 2 cm, representing stage T1cN0M0. Patients with tumors ≤ 1 cm who received chemotherapy did not have a significant difference in OS compared to the no-chemotherapy group (p = 0.41, hazard ratio (HR) 0.40, 95% confidence interval (CI) 0.021-2.5). However, patients with tumor sizes > 1 cm to 2 cm who received chemotherapy demonstrated significantly better OS compared to those without (p = 0.023, HR = 0.40, 95% CI 0.16-0.86). Patients with TNBC stage T1cN0M0 should receive adjuvant chemotherapy. For TNBC tumors ≤ 1 cm, avoidance of chemotherapy can be considered. Prospective research should further investigate the efficacy of chemotherapy in TNBC stages T1a-bN0M0.Trial Registration University of Windsor REB#16-119.

Impact of adjuvant chemotherapy on T1N0M0 breast cancer patients: a propensity score matching study based on SEER database and external cohort

BACKGROUND

There is no clear consensus on the benefits of adjuvant chemotherapy for tumor-node-metastasis (TNM) stage T1 (T1N0M0) breast cancer (BC). Our study investigated the effects of adjuvant chemotherapy on T1N0M0 BC patients.

METHODS

Seventy-five thousand one hundred thirty-nine patients diagnosed with T1N0M0 BC were selected from the Surveillance, Epidemiology, and End Results (SEER) database. Multivariate Cox analyses were performed to investigate the effects of adjuvant chemotherapy on T1a, T1b, and T1cN0M0 BC, including various tumor grades, and four molecular subtypes. Propensity score matching (PSM) was used to eliminate confounding factors and further compare the results between adjuvant chemotherapy and no adjuvant chemotherapy. Additionally, 545 T1N0M0 BC patients treated at the Northern Jiangsu People's Hospital were included as an independent external validation cohort. Univariate and multivariate Cox analyses were used to confirm the effects of adjuvant chemotherapy in T1a, T1b, and T1cN0M0 BC. Survival curves for the different tumor grades and molecular subtypes were plotted using the Kaplan-Meier method.

RESULTS

Adjuvant chemotherapy demonstrated a statistically significant improvement in overall survival (OS) in T1b and T1c BC, but not in T1a BC. Within T1b BC, adjuvant chemotherapy was found to have effects on grade III, and hormone receptor + (HoR +)/human epidermal growth factor receptor 2 + (HER2 +), HoR-/HER2 + , and HoR-/HER2- molecular subtypes, respectively. Adjuvant chemotherapy was beneficial to OS for grade II/III and T1c BC. Identical results were obtained after PSM. We also obtained similar results with external validation cohort, except that adjuvant chemotherapy made a difference in grade II and T1b BC of the external validation dataset.

CONCLUSIONS

Partial T1N0M0 BC patients with grade III T1bN0M0, patients with tumor grade II and III T1cN0M0, and excluding those with HoR + /HER2- subtype tumors, could obtain OS benefits from adjuvant chemotherapy.

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.

Systemic Therapy De-Escalation in Early-Stage Triple-Negative Breast Cancer: Dawn of a New Era?

Simple Summary

Triple-negative breast cancer is a life-threatening disease, even when identified at early stages. Recent advances have allowed the improvement of life expectancy via a personalized approach with the addition of newer chemotherapies, immunotherapies, and targeted therapies, but at the cost of added side effects. It has become increasingly clear that not all patients need such aggressive treatment. Here, we provide an overview of emerging opportunities to use less toxic therapies in patients at lower risk of recurrence or with mutations that can be effectively targeted using novel approaches. We provide a comprehensive review of completed and ongoing clinical trials with information on how to best stratify these patients for treatments to obtain maximum benefit without unnecessary toxicities.

Abstract

Early-stage triple negative breast cancer (TNBC) has been traditionally treated with surgery, radiation, and chemotherapy. The current standard of care systemic treatment of early-stage II and III TNBC involves the use of anthracycline-cyclophosphamide and carboplatin-paclitaxel with pembrolizumab in the neoadjuvant setting followed by adjuvant pembrolizumab per KEYNOTE-522. It is increasingly clear that not all patients with early-stage TNBC need this intensive treatment, thus paving the way for exploring opportunities for regimen de-escalation in selected subgroups. For T1a tumors (≤5 mm), chemotherapy is not used, and for tumors 6–10 mm (T1b) in size with negative lymph nodes, retrospective studies have failed to show a significant benefit with chemotherapy. In low-risk patients, anthracycline-free chemotherapy may be as effective as conventional therapy, as shown in some studies where replacing anthracyclines with carboplatin has shown non-inferior results for pathological complete response (pCR), which may form the backbone of future combination therapies. Recent advances in our understanding of TNBC heterogeneity, mutations, and surrogate markers of response such as pCR have enabled the development of multiple treatment options in the (neo)adjuvant setting in order to de-escalate treatment. These de-escalation studies based on tumor mutational status, such as using Poly ADP-ribose polymerase inhibitors (PARPi) in patients with BRCA mutations, and new immunotherapies such as PD1 blockade, have shown a promising impact on pCR. In addition, the investigational use of (bio)markers, such as high levels of tumor-infiltrating lymphocytes (TILs), low levels of tumor-associated macrophages (TAMs), and complete remission on imaging, also look promising. In this review, we cover the current standard of care systemic treatment of early TNBC and review the opportunities for treatment de-escalation based on clinical risk factors, biomarkers, mutational status, and molecular subtype.

Preneoplastic Low-Risk Mammary Ductal Lesions (Atypical Ductal Hyperplasia and Ductal Carcinoma In Situ Spectrum): Current Status and Future Directions

Intraepithelial mammary ductal neoplasia is a spectrum of disease that varies from atypical ductal hyperplasia (ADH), low-grade (LG), intermediate-grade (IG), to high-grade (HG) ductal carcinoma in situ (DCIS). While ADH has the lowest prognostic significance, HG-DCIS carries the highest risk. Due to widely used screening mammography, the number of intraepithelial mammary ductal neoplastic lesions has increased. The consequence of this practice is the increase in the number of patients who are overdiagnosed and, therefore, overtreated. The active surveillance (AS) trials are initiated to separate lesions that require active treatment from those that can be safely monitored and only be treated when they develop a change in the clinical/radiologic characteristics. At the same time, the natural history of these lesions can be evaluated. This review aims to evaluate ADH/DCIS as a spectrum of intraductal neoplastic disease (risk and histomorphology); examine the controversies of distinguishing ADH vs. DCIS and the grading of DCIS; review the upgrading for both ADH and DCIS with emphasis on the variation of methods of detection and the definitions of upgrading; and evaluate the impact of all these variables on the AS trials.

Benefit of adjuvant chemotherapy in node-negative T1a versus T1b and T1c triple-negative breast cancer

PURPOSE

National comprehensive cancer network guidelines recommend delivery of adjuvant chemotherapy in node-negative triple-negative breast cancer (TNBC) if the tumor is > 1 cm and consideration of adjuvant chemotherapy for T1b but not T1a disease. These recommendations are based upon sparse data on the role of adjuvant chemotherapy in T1a and T1b node-negative TNBC. Our objective was to clarify the benefits of chemotherapy for patients with T1N0 TNBC, stratified by tumor size.

METHODS

We performed a retrospective analysis of survival outcomes of TNBC patients at two academic institutions in the United States from 1999 to 2018. Primary tumor size, histology, and nodal status were based upon surgical pathology. The Kaplan-Meier plot and 5-year unadjusted survival probability were evaluated.

RESULTS

Among 282 T1N0 TNBC cases, the status of adjuvant chemotherapy was known for 258. Mean follow-up was 5.3 years. Adjuvant chemotherapy was delivered to 30.5% of T1a, 64.7% T1b, and 83.9% T1c (p < 0.0001). On multivariable analysis, factors associated with delivery of adjuvant chemotherapy were tumor size and grade 3 disease. Improved overall survival was associated with use of chemotherapy in patients with T1c disease (93.2% vs. 75.2% p = 0.008) but not T1a (100% vs. 100% p = 0.3778) or T1b (100% vs. 95.8% p = 0.2362) disease.

CONCLUSION

Our data support current guidelines indicating benefit from adjuvant chemotherapy in node-negative TNBC associated with T1c tumors but excellent outcomes were observed in the cases of T1a and T1b disease, regardless of whether adjuvant chemotherapy was delivered.

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.

Effects of adjuvant chemotherapy on recurrence rate in T1abN0M0 triple-negative breast cancer: A meta-analysis

PURPOSE

Triple-negative breast cancer (TNBC) is known for its higher recurrence rate in short-term (3-5 years) follow-up and limited systemic therapeutic methods (chemotherapy). Current literature debates over whether chemotherapy should be given to TNBC with a very early disease stage (T1a/bN0). This meta-analysis aimed to compare short-term recurrence rate between patients receiving adjuvant chemotherapy or not for this population.

METHODS

We performed a comprehensive search in databases including PubMed, Web of Science, Embase, and Cochrane library from January 2008 to December 2019. Raw data on local or distance recurrence events was extracted, odds ratio (OR) values, 95% confidence interval (CI) values, and P values were then calculated.

RESULTS

9 studies out of 426 were included in the meta-analysis. Our main results showed that breast cancer recurrence rate in T1a/bN0 TNBC patients receiving chemotherapy was significantly lower than those without chemotherapy (OR 0.54, 95% CI 0.37-0.78, P = 0.001). Similar results were detected in the T1b group (OR 0.45, 95% CI 0.26-0.78). The main result remained stable after sensitivity analysis. No significant publication bias was found.

CONCLUSIONS

Our results revealed that adjuvant chemotherapy reduced recurrence rate for T1mi/a/bN0 TNBC, especially for T1bN0. The benefit of chemotherapy for T1mi/aN0 disease is still debated.