Effects of Radiotherapy in Early-Stage, Low-Recurrence Risk, Hormone-Sensitive Breast Cancer

De-escalation of Post-mastectomy Irradiation in Hormone Receptor-Positive Breast Cancer with One to Three Positive Nodes

BACKGROUND

The 21-gene recurrence score (RS) is used to predict benefit from chemotherapy in hormone receptor (HR)-positive breast cancer with one to three positive lymph nodes. Prospective-retrospective studies have shown that the RS is prognostic for both systemic and locoregional recurrence in tamoxifen-treated patients. We aimed to assess whether RS could be utilized to predict a survival benefit from postmastectomy radiation therapy (PMRT).

PATIENTS AND METHODS

The National Cancer Database (NCDB) was used to identify women ≤ 75 years of age with HR+, HER2-negative, T1-3, N1, M0 breast cancer who underwent mastectomy and axillary staging with available RS during the years 2010-2016. Kaplan-Meier and Cox proportional hazards models were used to identify association between treatment and overall survival (OS). Univariate and multivariate analyses were used to identify variables correlating with PMRT and OS.

RESULTS

A total of 8907 patients were identified. Of the total, 3203 (36%) patients received adjuvant PMRT and 5704 (64%) did not. Across the entire cohort, 5-year OS was 97.5% for patients receiving PMRT and 96.8% for those who did not (P = 0.063). After adjusting for all covariates, in patients with RS ≤ 25, there was no statistically significant improvement in 5-year OS with the addition of adjuvant PMRT (97.5% versus 98.1% P = 0.093). Moreover, no survival benefit was seen with axillary node dissection (P = 0.58) or with the addition of chemotherapy (P = 0.312).

CONCLUSIONS

In our cohort of patients with one to three positive nodes and a RS ≤ 25, omission of post-mastectomy radiation therapy had no impact on OS. Our results suggest that RS may be utilized in the individualized decision making on PMRT.

The Prognostic and Predictive Value of Genomic Assays in Guiding Adjuvant Breast Radiation Therapy

Many patients with non-metastatic breast cancer benefit from adjuvant radiation therapy after lumpectomy or mastectomy on the basis of many randomized trials. However, there are many patients that have such low risks of recurrence after surgery that de-intensification of therapy by either reducing the treatment volume or omitting radiation altogether may be appropriate options. On the other hand, dose intensification may be necessary for more aggressive breast cancers. Until recently, these treatment decisions were based solely on clinicopathologic factors. Here, we review the current literature on the role of genomic assays as prognostic and/or predictive biomarkers to help guide adjuvant radiation therapy decision-making.

Effect of postmastectomy radiotherapy on pT1-2N1 breast cancer patients with different molecular subtypes: A real-world study based on the inverse probability of treatment weighting method

To investigate the significance of postmastectomy radiotherapy (PMRT) for different molecular subtypes of female breast cancer T1-2N1M0 based on inverse probability of treatment weighting (IPTW). The data of breast cancer patients diagnosed between 2010 and 2014 from the Surveillance, Epidemiology, and End Results (SEER) database were extracted. According to the status of hormone receptor (HR) and human epidermal growth factor receptor-2 (HER2), the patients were classified into luminal-A (HR+/HER2-), luminal-B (HR+/HER2+), HER2-enriched (HR-/HER2+), and TNBC (HR-/HER2-) subtypes. The association between radiation therapy and breast cancer-specific survival (BCSS) and Overall survival (OS) was retrospectively analyzed. Inverse probability of treatment weighting (IPTW) was applied to balance measurable confounders. Among the 16 894 patients, 6 055 (35.8%) were in the PMRT group and 10 839 (64.2%) were in the nonPMRT group, with a median follow-up of 48 months. There were 1003 deaths from breast cancer and 754 deaths from other causes. After IPTW, the covariates between groups reached complete equilibrium, the multifactorial Cox regression analysis showed that PMRT significantly prolonged OS and BCSS in Luminal-A and TNBC subtype breast cancer patients, yet it brought little significant survival advantage in Luminal-B and HER2-enriched subtype patients. Our study demonstrates a beneficial impact for PMRT on OS and BCSS among Luminal-A and TNBC subtype breast cancer patients with T1-2N1 disease.

Circ_0041732 regulates tumor properties of triple-negative breast cancer cells by the miR-149-5p/FGF5 pathway

BACKGROUND

Triple-negative breast cancer (TNBC) is a subtype of breast cancers with a high recurrence and mortality. The important factors promoting the TNBC process have not been fully identified. In this research, the role of a TNBC-related circular RNA (circRNA), circ_0041732, was revealed in TNBC cell tumor properties.

METHODS

The expression levels of circ_0041732, microRNA-149-5p (miR-149-5p) and fibroblast growth factor 5 (FGF5) were detected by quantitative real-time polymerase chain reaction. The protein expression was determined by Western blot analysis or immunohistochemistry assay. Cell proliferation was detected by cell counting kit-8 and cell colony formation assays. Cell apoptosis was analyzed by flow cytometry and caspase-3 activity assays. Cell migration and invasion were evaluated by wound-healing and transwell invasion assays. Cell angiogenic capacity was investigated by a tube formation assay. The targeting relationship between miR-149-5p and circ_0041732 or FGF5 was identified by dual-luciferase reporter and RNA immunoprecipitation assays. The impacts of circ_0041732 knockdown on tumor formation were determined by an in vivo assay.

RESULTS

Circ_0041732 and FGF5 expression were significantly upregulated, whereas miR-149-5p was downregulated in TNBC tissues and cells compared with normal breast tissues and cells, respectively. Circ_0041732 silencing inhibited TNBC cell proliferation, migration, invasion, and tube formation, but induced apoptosis. Additionally, circ_0041732 regulated TNBC cell tumor properties by binding to miR-149-5p. MiR-149-5p also modulated TNBC cell tumor properties by targeting FGF5. Furthermore, circ_0041732 knockdown hindered tumor formation in vivo.

CONCLUSION

Circ_0041732 silencing suppressed TNBC cell tumor properties by decreasing FGF5 expression through miR-149-5p. This finding demonstrated that circ_0041732 had the potential as a therapeutic target for TNBC.

Facilitating cancer systems epidemiology research

Systems epidemiology offers a more comprehensive and holistic approach to studies of cancer in populations by considering high dimensionality measures from multiple domains, assessing the inter-relationships among risk factors, and considering changes over time. These approaches offer a framework to account for the complexity of cancer and contribute to a broader understanding of the disease. Therefore, NCI sponsored a workshop in February 2019 to facilitate discussion about the opportunities and challenges of the application of systems epidemiology approaches for cancer research. Eight key themes emerged from the discussion: transdisciplinary collaboration and a problem-based approach; methods and modeling considerations; interpretation, validation, and evaluation of models; data needs and opportunities; sharing of data and models; enhanced training practices; dissemination of systems models; and building a systems epidemiology community. This manuscript summarizes these themes, highlights opportunities for cancer systems epidemiology research, outlines ways to foster this research area, and introduces a collection of papers, "Cancer System Epidemiology Insights and Future Opportunities" that highlight findings based on systems epidemiology approaches.

Circ-DONSON Knockdown Inhibits Cell Proliferation and Radioresistance of Breast Cancer Cells via Regulating SOX4

Background

Circular RNAs have been validated as critical regulators in the development of breast cancer (BC). Circ-DONSON is involved in the progression of glioma and gastric cancer. However, the biological role of circ-DONSON in BC remains unclear, and the aim of this study was to explore the biological role of circ-DONSON in BC.

Methods

Human tissue samples and BC cell lines were collected in this study. siRNAs against circ-DONSON were transfected into BC cell lines for silencing of circ-DONSON. Quantitative real-time PCR was used to test the circ-DONSON expression. Cell counting kit-8 (CCK-8), 5-bromo-2' deoxyuridine enzyme-linked immunosorbent assay (BrdU-ELISA), colony formation, and caspase-3 activity assays were used to assess cell proliferation, cell survival, and cell viability. Western blotting analysis was used to detect the protein expression levels.

Results

Our findings showed that circ-DONSON showed high expression in BC tissues and cell lines. CCK-8 and BrdU-ELISA assays showed that circ-DONSON knockdown inhibited BC cell proliferation. Moreover, cell survival, cell viability, and caspase-3 activity assays showed that circ-DONSON knockdown reduced the radioresistance of BC cells. Mechanistically, circ-DONSON regulated BC cell proliferation and radioresistance via SRY-box transcription factor 4 (SOX4). SOX4 overexpression significantly rescued the effect of circ-DONSON knockdown on BC cell proliferation and radioresistance. Moreover, circ-DONSON activated the Wnt/β-catenin pathway in BC cells via SOX4.

Conclusion

Our study concluded that circ-DONSON knockdown hindered cell proliferation and radioresistance through the SOX4/Wnt/β-catenin pathway in BC.

De-escalation of Endocrine Therapy in Early Hormone Receptor-positive Breast Cancer: When Is Local Treatment Enough?

OBJECTIVE

To identify subgroups of hormone receptor-positive (HR+) breast cancer patients that might not benefit from adding endocrine therapy (ET) to their local treatment.

BACKGROUND

De-escalation in breast cancer treatment has included surgery, radiation, and chemotherapy and has often focused on older patient populations. Systemic ET has yet to be de-escalated, though it carries serious side-effects, decreasing quality of life over 5 to 10 years. We hypothesize the 21-gene recurrence score (RS) could identify subgroups of younger patients whose long-term survival is unaffected by adjuvant ET.

METHODS

The National Cancer Database was used to identify women aged ≥50, with HR+, HER2-negative tumors, ≤3 cm in size, N0 status, and a RS≤25, who underwent breast-conserving surgery in 2010 to 2016. Kaplan-Meier and Cox proportional hazards models were used to identify association between treatment and overall survival (OS).

RESULTS

Of the 45,217 patients identified, 80.6% were 50 to 69 years old. 42,632 (94.3%) patients received ET and 2585 (5.7%) did not. The 5-year OS was 96.4% for patients receiving ET and 93.1% for those who did not (P < 0.001). After adjusting for all covariates, patients aged 50 to 69 with RS < 11 showed no statistically significant improvement in OS when adding ET to surgery, with or without radiation (P = 0.40). With RS 11 to 25, there was a significant improvement of OS with ET plus radiation (P < 0.001).

CONCLUSIONS

Local treatment only, with de-escalation of long-term ET, for patients aged 50 to 69 with RS < 11, seems not to impact OS and should have an anticipated quality of life improvement. Prospective studies investigating this approach are warranted.

Reflecting on 20 years of breast cancer modeling in CISNET: Recommendations for future cancer systems modeling efforts

Since 2000, the National Cancer Institute’s Cancer Intervention and Surveillance Modeling Network (CISNET) modeling teams have developed and applied microsimulation and statistical models of breast cancer. Here, we illustrate the use of collaborative breast cancer multilevel systems modeling in CISNET to demonstrate the flexibility of systems modeling to address important clinical and policy-relevant questions. Challenges and opportunities of future systems modeling are also summarized. The 6 CISNET breast cancer models embody the key features of systems modeling by incorporating numerous data sources and reflecting tumor, person, and health system factors that change over time and interact to affect the burden of breast cancer. Multidisciplinary modeling teams have explored alternative representations of breast cancer to reveal insights into breast cancer natural history, including the role of overdiagnosis and race differences in tumor characteristics. The models have been used to compare strategies for improving the balance of benefits and harms of breast cancer screening based on personal risk factors, including age, breast density, polygenic risk, and history of Down syndrome or a history of childhood cancer. The models have also provided evidence to support the delivery of care by simulating outcomes following clinical decisions about breast cancer treatment and estimating the relative impact of screening and treatment on the United States population. The insights provided by the CISNET breast cancer multilevel modeling efforts have informed policy and clinical guidelines. The 20 years of CISNET modeling experience has highlighted opportunities and challenges to expanding the impact of systems modeling. Moving forward, CISNET research will continue to use systems modeling to address cancer control issues, including modeling structural inequities affecting racial disparities in the burden of breast cancer. Future work will also leverage the lessons from team science, expand resource sharing, and foster the careers of early stage modeling scientists to ensure the sustainability of these efforts.

Since 2000, our research teams have used computer models of breast cancer to address important clinical and policy-relevant questions as part of the National Cancer Institute’s Cancer Intervention and Surveillance Modeling Network (CISNET). Our 6 CISNET breast cancer models embody the key features of systems modeling by incorporating numerous data sources and reflecting tumor, person, and health system factors that change over time and interact to represent the burden of breast cancer. We have used our models to investigate questions related to breast cancer biology, compare strategies to improve the balance of benefits and harms of screening mammography, and support insights into the delivery of care by modeling outcomes following clinical decisions about breast cancer treatment. Moving forward, our research will continue to use systems modeling to address issues related to reducing the burden of breast cancer including modeling structural inequities affecting racial disparities. Our future work will also leverage lessons from engaging multidisciplinary scientific teams, expand efforts to share modeling resources with other researchers, and foster the careers of early stage modeling scientists to ensure the sustainability of these efforts.

ndocrine therapy with accelerated artial breast irradiatin or exclusive ultra-accelerated artial breast irradiation for women aged ≥ 60 years with arly-stage breast cancer (EPOPE): The rationale for a GEC-ESTRO randomized phase III-controlled trial

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Epidemiologic data confirm the increase of breast cancer incidence in the elderly.

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The risk of recurrence of breast cancer is basically low.

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De-escalation breast cancer adjuvant therapy is justified in selected elderly patients.

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Ultra-accelerated breast irradiation with endocrine therapy omission is under debate.

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Prospective randomized trial is warranted.

Purpose

Breast cancer in the elderly has become a public health concern; there is a need to re-design its treatment with a view to de-escalation. Our paper sets out the rationale for a phase 3 randomized trial to evaluate less burdensome adjuvant procedures that remain effective and efficient.

Materials and methods

For low-risk breast cancer in the elderly, adjuvant treatment has been adjusted in order to make it more suitable and efficient. Hypofractionated radiation therapy based on accelerated or non-accelerated regimens as well as accelerated and ultra-accelerated partial breast irradiation (APBI) protocols were reviewed. Withdrawal of radiation (RT) or endocrine therapies (ET) from the adjuvant procedure were also investigated. Based on molecular and APBI classifications, inclusion criteria were discussed.

Results

Phase 3 randomized trials which compared standard vs. accelerated/non-accelerated hypofractionated regimens confirmed that the latter were non-inferior in terms of local control. Similarly, except for intraoperative-based techniques, APBI achieved non-inferior local control rates compared to whole breast irradiation for low-risk breast cancer. In phase 2 prospective trials using ultra APBI, encouraging results were observed regarding oncological outcome and toxicity profile. In phase 3 trials, adjuvant ET without RT significantly increased the rate of local relapse with no impact on overall survival while RT alone proved effective. Elderly patients aged 60 or more with low-risk, luminal A breast cancer were chosen as the target population in a phase 3 randomized trial comparing APBI + 5-year ET vs. uAPBI (16 Gy 1f) alone.

Conclusion

To investigate de-escalation adjuvant treatment for elderly breast cancer patients, we have defined a road map for testing more convenient strategies. This EPOPE phase 3 randomized trial is supported by the GEC-ESTRO breast cancer working group.

De-escalation of radiation therapy in patients with stage I, node-negative, HER2-positive breast cancer

In the modern era, highly effective anti-HER2 therapy is associated with low local-regional recurrence (LRR) rates for early-stage HER2+ breast cancer raising the question of whether local therapy de-escalation by radiation omission is possible in patients with small-node negative tumors treated with lumpectomy. To evaluate existing data on radiation omission, we used the National Cancer Database (NCDB) to test the hypothesis that RT omission results in equivalent overall survival (OS) in stage 1 (T1N0) HER2+ breast cancer. We excluded patients that received neoadjuvant systemic therapy. We stratified the cohort by receipt of adjuvant radiation. We identified 6897 patients (6388 RT; 509 no RT). Patients that did not receive radiation tended to be ≥70 years-old (odds ratio [OR] = 3.69, 95% CI: 3.02-4.51, p < 0.0001), to have ≥1 comorbidity (OR = 1.33, 95% CI: 1.06-1.68, p = 0.0154), to be Hispanic (OR = 1.49, 95% CI: 1.00-2.22, p = 0.049), and to live in lower income areas (OR = 1.32, 95% CI: 1.07-1.64, p = 0.0266). Radiation omission was associated with a 3.67-fold (95% CI: 2.23-6.02, p < 0.0001) increased risk of death. While other selection biases that influence radiation omission likely persist, these data should give caution to radiation omission in T1N0 HER2+ breast cancer.

Personalization in Modern Radiation Oncology: Methods, Results and Pitfalls. Personalized Interventions and Breast Cancer

Breast cancer, the most frequent malignancy in women worldwide, is a heterogeneous group of diseases, characterized by distinct molecular aberrations. In precision medicine, radiation oncology for breast cancer aims at tailoring treatment according to tumor biology and each patient’s clinical features and genetics. Although systemic therapies are personalized according to molecular sub-type [i.e. endocrine therapy for receptor-positive disease and anti-human epidermal growth factor receptor 2 (HER2) therapy for HER2-positive disease] and multi-gene assays, personalized radiation therapy has yet to be adopted in the clinical setting. Currently, attempts are being made to identify prognostic and/or predictive factors, biomarkers, signatures that could lead to personalized treatment in order to select appropriate patients who might, or might not, benefit from radiation therapy or whose radiation therapy might be escalated or de-escalated in dosages and volumes. This overview focuses on what has been achieved to date in personalized post-operative radiation therapy and individual patient radiosensitivity assessments by means of tumor sub-types and genetics.

Impact of Oncotype DX Recurrence Score on the Patterns of Locoregional Recurrence in Breast Cancer (Korean Radiation Oncology Group 19-06)

The current study evaluated the impact of the Oncotype DX recurrence score (RS) on the patterns of locoregional recurrence (LRR) in node-negative, hormone receptor-positive/human epidermal growth factor receptor 2-negative breast cancer. Totally, 339 patients from 4 institutions were enrolled and analyzed retrospectively. All patients underwent breast-conserving surgery followed by whole-breast irradiation; only 2 patients received regional nodal irradiation (RNI). The RS was < 11 in 55 patients, 11–25 in 241, and > 25 in 43. Sixty-two patients received adjuvant chemotherapy. All patients except 4 received hormonal therapy. During a 62-month median follow-up, local recurrence was observed in 1 patient; regional recurrence, 3; and distant metastasis, 7. All LRRs were observed among patients with a RS > 25, resulting in a 5-year LRR rate of 7.3% in this subgroup. Regional recurrences developed in patients did not receive RNI initially. Thus, RNI might be effective for patients with a high RS.

Circular RNA hsa_circ_0131242 Promotes Triple-Negative Breast Cancer Progression by Sponging hsa-miR-2682

Objective

CircRNAs are emerging as vital regulators in a variety of cancers. However, the expression pattern and potential mechanism of circRNAs in triple-negative breast cancer remain unclear. In this study, we aim to systematically investigate circRNAs alteration in triple-negative breast cancer tissues.

Methods

Microarray and bioinformatics analyses were used to identify circRNAs expression in cancer tissues. qRT-PCR was conducted to measure the expression of RNAs. Cell Counting Kit‐8, wound-healing and transwell assays were conducted to investigate the function of circRNAs. Dual-luciferase reporter assay was performed to validate target binding.

Results

Hsa_circ_0131242 was highly expressed in both cancer tissues and cell lines compared to control. Subsequently, statistical analyses revealed that high expression of hsa_circ_0131242 was positively correlated with advanced tumor stages and poorer clinical features in cancer patients. Hsa_circ_0131242 knockdown could suppress the progression of breast cancer cells. Bioinformatics prediction and luciferase reporter assay showed that hsa_circ_0131242 acted as a sponge for hsa-miR-2682. Moreover, co-transfection of hsa-miR-2682 inhibitor and si-hsa_circ_0131242 rescued cell proliferation and migration in BT549 and MDA-MB-468 cell lines.

Conclusion

Our study identified hsa_circ_0131242 expression in TNBC for the first time and found that hsa_circ_0131242 may promote triple-negative breast cancer progression by sponging hsa-miR-2682.

Multigene testing in breast cancer: What have we learned from the 21-gene recurrence score assay?

Most invasive breast cancers express hormone receptors (HR) and typically have a favorable prognosis following endocrine therapy. Patients at a higher risk of recurrence can be identified by multigene prognostic classifiers such as the 21-gene recurrence score (RS) assay, 70-gene prognostic signature, PAM-50, 12-gene molecular score, and others. The 21-gene RS assay (Oncotype Dx™, Genomic Health, Redwood City, CA) has level I clinical evidence and is the most widely used multigene assay in North America. The RS assay is based on reverse transcriptase polymerase chain reaction that can be performed on the RNA isolated from formalin-fixed paraffin-embedded tissue. It evaluates the expression of 16 cancer-related genes developed based on a multi-step approach. Due to its ability to assess recurrence risk and predict potential benefit from chemotherapy, the assay is recommended for patients with node-negative, HR-positive, and human epidermal growth factor receptor 2 (HER2)-negative breast cancer by the American Society of Clinical Oncology, National Comprehensive Cancer Network clinical practice guidelines in oncology, European Society for Medical Oncology clinical practice guidelines, and St. Gallen consensus panel guidelines. The RS assay has also been incorporated in the prognostic stage groups in the 8th edition of the American Joint Commission of Cancer staging manual in order to provide essential genomic information for optimal treatment decisions. This review will focus on the utility of the RS assay in HR-positive and HER2-negative breast cancer patients, including risk of distant and locoregional recurrence in node-negative and node-positive tumors, association with radiotherapy, special subtypes of breast cancer, practical issues related to selecting tumors for testing, and overview of the recently published TailorX (Trial Assigning IndividuaLized Options for treatment [Rx]) results.

Impact of older age on local treatment decisionss

Managing elderly breast cancer patients brings challenges both to physicians and patients themselves. There are certain controversial issues regarding local treatment of early breast cancer in this population. Since elderly patients are more likely to have comorbidities and functional limitations, they are more prone to undertreatment. Although surgical treatment in elderly patients were reported to be safe, severity and number of comorbidities are shown to be related with increased complications, hence may lead to higher mortality and lower life quality. Therefore, frailty is one of the concerns which prevents elderly patients to receive standard-of-care local treatment. Nevertheless, breast cancers developing in elderly are more likely to be low grade and luminal type. Until now, primary endocrine treatment without surgical resection, omitting whole breast irradiation after partial mastectomy and avoiding sentinel lymph node biopsy, which are otherwise accepted as standard-of-care, were questionned in healthy, low-risk, elderly fit patients. Two main issues were suggested to be considered when assessing the impact of local treatment options in this patient group; the clinical significance of treatments' effects, and the patients' expectations. Due to their vulnerability, baseline geriatric assessment should be the initial step for management in elderly breast cancer patients. Even in those who are healthy and fit with long life-expectancy, de-escalation in management might be an option in low-risk patients after considering patients' individual expectations and limited clinical benefits of standard local treatment options.

Breast Cancer: A Molecularly Heterogenous Disease Needing Subtype-Specific Treatments

Breast cancer is the most commonly occurring cancer in women. There were over two-million new cases in world in 2018. It is the second leading cause of death from cancer in western countries. At the molecular level, breast cancer is a heterogeneous disease, which is characterized by high genomic instability evidenced by somatic gene mutations, copy number alterations, and chromosome structural rearrangements. The genomic instability is caused by defects in DNA damage repair, transcription, DNA replication, telomere maintenance and mitotic chromosome segregation. According to molecular features, breast cancers are subdivided in subtypes, according to activation of hormone receptors (estrogen receptor and progesterone receptor), of human epidermal growth factors receptor 2 (HER2), and or BRCA mutations. In-depth analyses of the molecular features of primary and metastatic breast cancer have shown the great heterogeneity of genetic alterations and their clonal evolution during disease development. These studies have contributed to identify a repertoire of numerous disease-causing genes that are altered through different mutational processes. While early-stage breast cancer is a curable disease in about 70% of patients, advanced breast cancer is largely incurable. However, molecular studies have contributed to develop new therapeutic approaches targeting HER2, CDK4/6, PI3K, or involving poly(ADP-ribose) polymerase inhibitors for BRCA mutation carriers and immunotherapy.

Expected Monetary Impact of Oncotype DX Score-Concordant Systemic Breast Cancer Therapy Based on the TAILORx Trial

BACKGROUND

TAILORx demonstrated that women with node-negative, hormone receptor-positive, HER2-negative breast cancers and Oncotype DX recurrence scores (RS) of 0-25 had similar 9-year outcomes with endocrine vs chemo-endocrine therapy; evidence for women aged 50 years and younger and RS 16-25 was less clear. We estimated how expected changes in practice following the trial might affect US costs in the initial 12 months of care (initial costs).

METHODS

Data from Surveillance, Epidemiology, and End Results (SEER), SEER-Medicare, and SEER-Genomic Health Inc datasets were used to estimate Oncotype DX testing and chemotherapy rates and mean initial costs pre- and post-TAILORx (in 2018 dollars), assuming all women received Oncotype DX testing and score-suggested therapy posttrial. Sensitivity analyses tested the impact on costs of assumptions about compliance with testing and score-suggested treatment and estimation methods.

RESULTS

Pretrial mean initial costs were $2.816 billion. Posttrial, Oncotype DX testing costs were projected to increase from $115 to $231 million and chemotherapy use to decrease from 25% to 17%, resulting in initial care costs of $2.766 billion, or a net savings of $49 million (1.8% decrease). A small net savings was seen under most assumptions. The one exception was if all women aged 50 years and younger with tumors with RS 16-25 elected to receive chemotherapy, initial care costs could increase by $105 million (4% increase).

CONCLUSIONS

Personalizing breast cancer treatment based on tumor genetic profiles could result in small cost decreases in the initial 12 months of care. Studies are needed to evaluate the long-term costs and nonmonetary benefits of personalized cancer care.

Commercially Available Gene Expression Assays as Predictive Tools for Adjuvant Radiotherapy? A Critical Review

Background

Gene expression assays are increasingly used for decision-making regarding adjuvant chemotherapy in patients with hormone receptor-positive, HER2-negative breast cancer. There are some clinical situations in which there is also a need for better prognostic and predictive markers to better estimate the amount of benefit from adjuvant radiotherapy. The rising availability of gene expression analyses prompts the question whether their results can also be used to guide clinical decisions regarding adjuvant radiation.

Summary

Multiple studies suggest a correlation between results from gene expression assays and locoregional recurrence rates. Only few publications addressed the predictive value of results from gene expression analysis for the role of adjuvant radiotherapy in different settings.

Key Messages

To date, the available evidence on the possible predictive value of gene expression assays for radiotherapy does not support their inclusion into the decision-making process for adjuvant radiation. This is due to methodological weaknesses and limitations regarding patient selection, the nonrandomized design of all studies in terms of radiotherapy use, and limited availability of tissue from prospective trials. Thus, utilization of the present knowledge for clinical indication of radiotherapy should be very cautious.

Clinicogenomic Radiotherapy Classifier Predicting the Need for Intensified Locoregional Treatment After Breast-Conserving Surgery for Early-Stage Breast Cancer

PURPOSE

Most patients with early-stage breast cancer are treated with adjuvant radiotherapy (RT) after breast-conserving surgery (BCS) to prevent locoregional recurrence (LRR). However, no genomic tools are used currently to select the optimal RT strategy.

METHODS

We profiled the transcriptome of primary tumors on a clinical grade assay from the SweBCG91-RT trial, in which patients with node-negative breast cancer were randomly assigned to either whole-breast RT after BCS or no RT. We derived a new classifier, Adjuvant Radiotherapy Intensification Classifier (ARTIC), comprising 27 genes and patient age, in three publicly available cohorts, then independently validated ARTIC for LRR in 748 patients in SweBCG91-RT. We also compared previously published genomic signatures for ability to predict benefit from RT in SweBCG91-RT.

RESULTS

ARTIC was highly prognostic for LRR in patients treated with RT (hazard ratio [HR], 3.4; 95% CI, 2.0 to 5.9; P < .001) and predictive of RT benefit (P_interaction = .005). Patients with low ARTIC scores had a large benefit from RT (HR, 0.33 [95% CI, 0.21 to 0.52], P < .001; 10-year cumulative incidence of LRR, 6% v 21%), whereas those with high ARTIC scores benefited less from RT (HR, 0.73 [95% CI, 0.44 to 1.2], P = .23; 10-year cumulative incidence of LRR, 25% v 32%). In contrast, none of the eight previously published signatures were predictive of benefit from RT in SweBCG91-RT.

CONCLUSION

ARTIC identified women with a substantial benefit from RT as well as women with a particularly elevated LRR risk in whom whole-breast RT was not sufficiently effective and, thus, in whom intensified treatment strategies such as tumor-bed boost, and possibly regional nodal RT, should be considered. To our knowledge, ARTIC is the first classifier validated as predictive of benefit from RT in a phase III clinical trial with patients randomly assigned to receive or not receive RT.

Estimating the benefits of therapy for early-stage breast cancer: the St. Gallen International Consensus Guidelines for the primary therapy of early breast cancer 2019

BACKGROUND

The 16th St. Gallen International Breast Cancer Conference 2019 in Vienna, Austria reviewed substantial new evidence on loco-regional and systemic therapies for early breast cancer.

DESIGN

Treatments were assessed in light of their intensity, duration and side-effects, estimating the magnitude of clinical benefit according to stage and biology of the disease. The Panel acknowledged that for many patients, the impact of adjuvant therapy or the adherence to specific guidelines may have modest impact on the risk of breast cancer recurrence or overall survival. For that reason, the Panel explicitly encouraged clinicians and patients to routinely discuss the magnitude of benefit for interventions as part of the development of the treatment plan.

RESULTS

The guidelines focus on common ductal and lobular breast cancer histologies arising in generally healthy women. Special breast cancer histologies may need different considerations, as do individual patients with other substantial health considerations. The panelists' opinions reflect different interpretation of available data and expert opinion where is lack of evidence and sociocultural factors in their environment such as availability of and access to medical service, economic resources and reimbursement issues. Panelists encourage patient participation in well-designed clinical studies whenever available.

CONCLUSIONS

With these caveats in mind, the St. Gallen Consensus Conference seeks to provide guidance to clinicians on appropriate treatments for early-stage breast cancer and guidance for weighing the realistic tradeoffs between treatment and toxicity so that patients and clinical teams can make well-informed decisions on the basis of an honest reckoning of the magnitude of clinical benefit.

[Individual modification of the dose, volume and fractionation of breast radiotherapy]

Randomized trials demonstrated similar overall survival between mastectomy and breast-conservative surgery followed by adjuvant radiation therapy. Breast-conservative surgery, with adjuvant radiation therapy, with or without neoadjuvant systemic therapy has become the standard of care for women with early or locally advanced breast cancer. Nevertheless, certain cardiac, lung or cutaneous toxicities may alter the long-term body image and the quality of life of a limited number of patients who consider having had "overtreatment" or treatment outside the best knowledge of science. In case of low-risk breast cancer, several trials have evaluated the carcinologic outcome in absence of radiation therapy after breast-conservative surgery. Local recurrences increased in case of breast-conservative surgery alone but without impact on overall survival. Multiple debates have emerged in order to select the most appropriate evaluation criteria. Finally, a large consensus has considered that reducing local recurrences is important but with modern technologies and after identifying patients of individual radiosensitivity. Indeed, in case of a low absolute risk of local recurrence, radiation therapy techniques have been developed to allow a focal treatment especially for patients with high risk of developing late effects. This kind of compromise takes into account the reduction risk of local recurrences but also the probability of developing radiation-induced cutaneous sequelae. In the same way, for patients considered at high risk of recurrence, the huge volumes need specific techniques to better cover the targets while protecting the surrounding critic organs such as heart and lung. Intensity-modulated radiation therapy and the local high boost may help to decrease local recurrences of these more extended and aggressive diseases while considering the individual radiosensitivity that paves the way of long-term sequelae. In this article, we detail a personalized approach of breast radiation therapy considering the absolute risk of local recurrences and the probability of radiation-induced toxicity appearance.

Survival following radiotherapy in young women with localized early-stage breast cancer according to molecular subtypes

Background

To evaluate the significance and benefit of radiotherapy (RT) in young early‐stage breast cancer patients according to different molecular subtypes.

Methods

We conducted a retrospective cohort study utilizing the Surveillance, Epidemiology, and End Results database with known hormone receptor (HoR) and human epidermal growth factor receptor 2 (HER2) status. Female patients aged 18‐45, received RT treatment, and diagnosed with stage T1‐3, N0‐3, M0 primary breast cancer between 2010 and 2013 were identified.

Results

Of all the 23 148 included patients, 14 708 (63.54%), 3385 (14.62%), 1225 (5.29%), and 3830 (16.55%) were diagnosed with luminal‐A (HoR + HER2‐), luminal‐B (HoR + HER2+), HER2‐enriched (HoR‐HER2+), and triple‐negative (HoR‐HER2‐) breast cancer, respectively. RT was significantly correlated with improved overall survival (OS, HR: 0.295; 95% CI:0.138‐0.63, P = 0.002) and breast cancer‐specific survival (BCSS, HR: 0.328; 95% CI: 0.153‐0.702, P = 0.004) in HER2‐enriched patients. In addition, a significantly prolonged OS was also observed when RT was given to luminal‐A (HR: 0.696; 95% CI: 0.538‐0.902, P = 0.006) and luminal‐B (HR: 0.385; 95% CI:0.199‐0.744, P = 0.005) breast cancer patients compared to those without RT. Multivariable‐adjusted analyses showed that HER2 was a significant favorable factor for RT benefit in breast cancer patients.

Conclusions

RT could offer significant survival benefit in luminal‐A, luminal‐B, and especially HER2‐enriched young early‐stage breast cancer female patients. The results enabled clinicians to predict the benefits of RT and improve evidence‐based treatment for breast cancer patients.

Effect of 21-gene recurrence score in decision-making for surgery in early stage breast cancer

Aim

We aimed to assess the role of 21-gene recurrence score (RS) in the decision-making for surgical treatment in early stage breast cancer and compared the outcomes between breast-conserving surgery (BCS) and mastectomy (MAST) among various 21-gene RS groups.

Methods

We included patients with stage T1-2M0M0 and estrogen receptor-positive breast invasive ductal carcinoma who underwent BCS + radiotherapy or MAST between 2004 and 2012 as part of the Surveillance, Epidemiology, and End Results program. Data were analyzed using binomial logistic regression, multivariate Cox proportional hazards models, and propensity score matching (PSM).

Results

We enrolled 34,447 patients including 22,681 (65.8%) and 11,766 (34.2%) who underwent BCS and MAST, respectively. Patients with high-risk RS were more likely to receive MAST. Multivariate analysis indicated that patients with intermediate-risk (P<0.001) and high-risk (P<0.001) RS had poor breast cancer-specific survival (BCSS), as compared to those with low-risk RS. Moreover, patients who underwent MAST also exhibited poor BCSS (P<0.001), as compared to those who underwent BCS. In low-risk (P<0.001) and intermediate-risk (P=0.020) RS groups, patients who underwent MAST had poor BCSS, as compared to those treated with BCS. However, BCSS was comparable between patients who underwent MAST and BCS (P=0.952); similar trends were also observed after PSM.

Conclusion

The 21-gene RS may impact the decision-making for surgery in early stage breast cancer. Our study provides additional support for a shared decision-making process for BCS when both local management options are appropriate choices regardless of the 21-gene RS.

The 21-gene recurrence score and effects of adjuvant radiotherapy after breast conserving surgery in early-stage breast cancer

Aim: To investigate the associations with the 21-gene recurrence score (RS) and effect of adjuvant radiotherapy (RT) for early-stage breast cancer after breast conserving surgery. Methods: We included 13,246 patients in the SEER database. Results: Patients with a higher RS were independently related to nonreceipt of RT (p < 0.001). In both the traditional and Trial Assigning Individualized Options for Treatment (TAILORx) RS cut-offs, the receipt of RT was not related to better breast cancer-specific survival in low- and high-risk RS groups, but was independently related to better breast cancer-specific survival in intermediate-risk RS group before (p = 0.029) and after (p = 0.001) propensity score matching. Conclusion: The 21-gene-RS may impact the decision-making of adjuvant RT in early-stage breast cancer after breast conserving surgery. The survival benefit of adjuvant RT may be limited to patients with intermediate-risk RS.

21-Gene Recurrence Score Assay and Outcomes of Adjuvant Radiotherapy in Elderly Women With Early-Stage Breast Cancer After Breast-Conserving Surgery

Introduction: To assess the role of the 21-gene recurrence score (RS) assay on decision-making of postoperative radiotherapy (RT) following breast-conserving surgery (BCS) in elderly women with early-stage breast cancer. Methods: The 21-gene RS for elderly (≥65 years) women with stage T1-2N0M0 estrogen receptor-positive breast cancer who underwent BCS from 2004 to 2015 was obtained from the Surveillance, Epidemiology, and End Results program. We estimated the association of 21-gene RS and adjuvant RT related to breast cancer-specific survival (BCSS) using propensity score matching (PSM). Results: We identified 18,456 patients, of which 15,326 (83.0%) received postoperative RT. Of identified patients, 58.9, 34.0, and 7.1% of patients had a low-, intermediate-, and high-risk RS, respectively. Receipt of postoperative RT was not related to the year of diagnosis according to the 21-gene RS groups. Multivariate analysis suggested that receipt of postoperative RT was an independent predictor of better BCSS before (hazard ratio [HR] 0.587, 95% confidence interval [CI] 0.426-0.809, P = 0.001) and after (HR 0.613, 95%CI 0.390-0.963, P = 0.034) PSM. However, subgroups analyses indicated that receipt of postoperative RT was related to better BCSS in women with intermediate-risk RS before (HR 0.467, 95%CI 0.283-0.772, P = 0.003) and after (HR 0.389, 95%CI 0.179-0.846, P = 0.017) PSM, but not in women with low- and high-risk RS groups before and after PSM. Conclusions: Although causation cannot be implied, adjuvant RT in elderly women was associated with a greater effect size in patients with an intermediate-risk RS.

The effects of postoperative radiotherapy on survival outcomes in patients under 65 with estrogen receptor positive tubular breast carcinoma

Background

The value of postoperative radiotherapy in tubular breast carcinoma patients under 65 years is uncertain.

Methods

Data on patients with estrogen receptor positive T1N0M0 tubular breast carcinoma who were younger than 65 years and who received breast-conserving surgery between 2000 and 2013 were retrieved from the Surveillance, Epidemiology and End Results database. Demographic, clinicopathologic features, and receipt of postoperative radiotherapy were analyzed to investigate effects on survival.

Results

Data from 2442 patients were analyzed, of whom 2020 (82.7%) received postoperative radiotherapy and 422 (17.3%) did not. The number of patients treated with or without postoperative radiotherapy showed no differences during the study period (p = 0.184). Radiotherapy was more likely to be administered in patients with well differentiated tumors. Multivariate Cox analysis showed that postoperative radiotherapy delivery was significantly correlated with better breast cancer-specific survival (BCSS) (hazard ratio [HR] 0.297, 95% confidence interval [CI] 0.105–0.836, p = 0.022) and overall survival (OS) (HR 0.656, 95% CI 0.441–0.978, p = 0.038). Ten 10-year BCSS was 99.3% in patients who received postoperative radiotherapy and 98.1% in those who did not (p = 0.020), and 10-year OS was 93.4 and 91.0%, respectively (p = 0.029). Postoperative radiotherapy increased BCSS and OS in the subgroups of age < 50 years, non-Hispanic white, well differentiated tumors, and progesterone receptor positive tumors.

Conclusions

Postoperative radiotherapy after breast-conserving surgery improved survival outcomes in tubular breast carcinoma patients aged < 50 years. However, omitting postoperative radiotherapy may not decrease survival in patients aged ≥50 years.