Local recurrence after breast-conserving therapy in relation to gene expression patterns in a large series of patients

Individualising radiation therapy decisions in breast cancer patients based on tumour infiltrating lymphocytes and genomic biomarkers

Radiation therapy (RT) has long been fundamental for the curative treatment of breast cancer. While substantial progress has been made in the anatomical and technological precision of RT delivery, and some approaches to de-escalate or omit RT based on clinicopathologic features have been successful, there remain substantial opportunities to refine individualised RT based on tumour biology. A major area of clinical and research interest is to ascertain the individualised risk of loco-regional recurrence to direct treatment decisions regarding escalation and de-escalation of RT. Patient-tailored treatment with RT is considerably lagging behind compared with the massive progress made in the field of personalised medicine that currently mainly applies to decisions on the use of systemic therapy or targeted agents. Herein we review select literature surrounding the use of tumour genomic biomarkers and biomarkers of the immune system, including tumour infiltrating lymphocytes (TILs), within the management of breast cancer, specifically as they relate to progress in moving toward analytically validated and clinically tested biomarkers utilized in RT.

Development and Validation of a Genomic Profile for the Omission of Local Adjuvant Radiation in Breast Cancer

PURPOSE

Adjuvant radiotherapy (RT) is used for women with early-stage invasive breast cancer treated with breast-conserving surgery. However, some women with low risk of recurrence may safely be spared RT. This study aimed to identify these women using a molecular-based approach.

METHODS

We analyzed two randomized trials of women with node-negative invasive breast cancer to ± RT following breast-conserving surgery: SweBCG91-RT (stage I-II, no adjuvant systemic therapy) and Princess Margaret (age 50 years or older, T1-T2, adjuvant tamoxifen). Transcriptome-wide profiling was performed (Affymetrix Human Exon 1.0 ST microarray). Patients with estrogen receptor-positive/human epidermal growth factor receptor 2-negative tumors and with gene expression data were included. The SweBCG91-RT cohort was divided into training (N = 243) and validation (N = 354) cohorts. A 16-gene signature named Profile for the Omission of Local Adjuvant Radiation (POLAR) was trained to predict locoregional recurrence (LRR) using elastic net regression. POLAR was then validated in the SweBCG91-RT validation cohort and the Princess Margaret cohort (N = 132).

RESULTS

Patients categorized as POLAR low-risk without RT had a 10-year LRR of 6% (95% CI, 2 to 16) and 7% (0 to 27) in SweBCG91-RT and Princess Margaret cohorts, respectively. There was no significant benefit from RT in POLAR low-risk patients (hazard ratio [HR], 1.1 [0.39 to 3.4], P = .81, and HR, 1.5 [0.14 to 16], P = .74, respectively). Patients categorized as POLAR high-risk had a significant decreased risk of LRR with RT (HR, 0.43 [0.24 to 0.78], P = .0055, and HR, 0.25 [0.07 to 0.92], P = .038, respectively). An exploratory analysis testing for interaction between RT and POLAR in the combined validation cohort was performed (P = .066).

CONCLUSION

The novel POLAR genomic signature on the basis of LRR biology may identify patients with a low risk of LRR despite not receiving RT, and thus may be candidates for RT omission.

Determining prognostic factors and optimal surgical intervention for early-onset triple-negative breast cancer

Background

Few studies have focused specifically on prognostic factors and optimal surgical intervention for early-onset triple-negative breast cancer (eTNBC), which is characterized by high malignancy and poor prognosis.

Methods

We performed a cohort study with a median follow-up of 31 months using Surveillance, Epidemiology, and End Results (SEER) data of patients diagnosed with stages I–III eTNBC between 2010 and 2016. In addition, we collected cases between 2006 and 2016 from our center as an external validation set. Clinical features, pathologic characteristics and oncologic outcomes were analyzed. Prognostic factors for overall survival (OS) and breast cancer-specific survival (BCSS) were determined by Cox proportional hazards analyses and were incorporated into the prognostic nomogram. Subgroup analysis based on propensity score matching method was conducted to explore the subset of patients that would benefit from breast-conserving therapy (BCT).

Results

Based on SEER dataset, patients with eTNBC were more likely to undergo mastectomy than BCT. On multivariable analysis, patients with better survival outcomes were those not married, uninsured, had higher T and N stage, and had histological type of mixed invasive ductal and lobular carcinoma. The prognostic nomogram based on these variables successfully predicted the 3- and 5-year BCSS (C-index in training cohort, 0.774; in validation cohort from SEER, 0.768; in validation cohort from our center, 0.723). Subgroup analysis illustrated that patients with T1N0M0 or T2-4N+M0 tumors who underwent BCT achieved longer overall survival than those who underwent mastectomy (for T1N0M0, P = 0.022; for T2-4N+M0, P = 0.003); however, the type of surgery did not influence OS among patients with T1N+M0 or T2-4N0M0 tumors (for T1N+M0, P = 0.305; for T2-4N0M0, P = 0.317).

Conclusions

The prognosis of patients with eTNBC is mainly affected by marital status, insurance status, T stage, N stage and histological type. The prognostic nomogram based on these factors is quite reliable. Subgroup analysis suggested that BCT may be a superior option for patients with eTNBC, especially those with T1N0M0 and T2-4N+M0 tumors.

Genomically Guided Breast Radiation Therapy: A Review of the Current Data and Future Directions

Purpose

To highlight the current evidence and the limitations in data to support a personalized approach in breast oncology radiation therapy management and define steps needed for clinical implementation.

Methods and Materials

A critical review of the current literature on the use of genomics in breast radiation therapy was undertaken by a group of breast radiation oncologists to discuss current data, future directions, and challenges.

Results

A summary of the existing data, ongoing clinical trials, and future directions is provided. The authors note many groups have developed radiation-specific genomic assays, which demonstrate promise in prediction of local control and benefit from radiation therapy; however, prospective validation of their utility is needed. Limitations continue to exist in our understanding of tumor biology and how it can be integrated into clinical practice.

Conclusions

Given the relative ubiquity of breast radiation therapy, the variety of dose and fractionation approaches, and the current data to support a personalized approach, it is our belief that the delivery of breast radiation therapy is uniquely poised for a genomically personalized radiation therapy approach. Prospective clinical trials implementing genomic signatures are needed at this time to advance the field.

Outcomes after breast-conserving surgery or mastectomy in patients with triple-negative breast cancer: meta-analysis

BACKGROUND

In patients with triple-negative breast cancer (TNBC), oncological and survival outcomes based on locoregional treatment are poorly understood. In particular, the safety of breast-conserving surgery (BCS) for TNBC has been questioned.

METHODS

A meta-analysis was performed to evaluate locoregional recurrence (LRR), distant metastasis (DM), and overall survival (OS) rates in patients with TNBC who had breast-conserving surgery versus mastectomy. Estimates were pooled in random-effects analysis. The effect of study-level co-variables was assessed by univariable metaregression.

RESULTS

Fourteen studies, including 19 819 patients operated for TNBC met the inclusion criteria; 9828 patients (49.6 per cent) underwent BCS and 9991 (50.4 per cent) had a mastectomy. Patients with smaller tumours were more likely to be selected for BCS (pooled odds ratio (OR) for T1 tumours 1.95, 95 per cent c.i. 1.64 to 2.32; P < 0.001). The pooled OR for LRR was 0.64 (0.48 to 0.85; P = 0.002), indicating a statistically significantly lower odds of LRR among women who had BCS relative to mastectomy. The pooled OR for DM was 0.70 (0.53 to 0.94; P = 0.02), indicating a lower odds of DM among women who had BCS; however, this difference diminished with increasing study-level age and follow-up time. A pooled hazard ratio of 0.78 (0.69 to 0.89; P < 0.001) showed a significantly lower hazard for all-cause mortality among women undergoing BCS versus mastectomy.

CONCLUSION

These results should be interpreted cautiously owing to likely differences in selection for BCS or mastectomy in the included studies. Patients with TNBC selected for BCS do not, however, have a worse prognosis than those treated with mastectomy, and breast conservation can be offered when feasible clinically.

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.

A case-control study to identify molecular risk factors for local recurrence in young breast cancer patients

PURPOSE

To investigate risk factors for local recurrence (LR) after breast conserving therapy in young breast cancer patients randomized in the "Young Boost Trial".

MATERIAL & METHODS

In the "Young Boost Trial" 2421 patients ≤50 years old were randomized between a 16 Gy and 26 Gy boost after breast conserving surgery and whole breast radiation (50 Gy). We performed a case-control study comparing patients who developed a LR (cases) and for each of them three control patients free of recurrence (controls). Clinicopathological factors, copy number- and gene expression profiles of primary tumors were compared between cases and controls, and between primary tumors and local recurrences.

RESULTS

The cumulative 5-year LR rate was 1.07% (95% CI 0.72-1.59%) and 10-year LR rate 2.56% (1.81-3.62%). Analysis of a subset of primary tumors and local recurrences showed similar histopathological characteristics (n = 15), copy number (n = 13) and gene expression profiles (n = 14). Basal subtype was strongly associated with LR in univariable and multivariable analysis. Gains of CCND1 were identified more frequently among controls, while more frequent gains of FGFR1 and IGF1R were observed among cases. Upregulation of genes involved in the p53-pathway was observed in recurring tumors compared to non-recurring tumors. We could not identify a genomic classifier for LR.

CONCLUSIONS

All investigated local recurrences were true genomic recurrences. Although differences in copy number variation and gene expression pathways were observed in recurring tumors compared to non-recurring tumors, no genomic classifier for LR could be identified.

Precision Medicine and the Role of Biomarkers of Radiotherapy Response in Breast Cancer

Radiotherapy remains an important treatment modality in nearly two thirds of all cancers, including the primary curative or palliative treatment of breast cancer. Unfortunately, largely due to tumor heterogeneity, tumor radiotherapy response rates can vary significantly, even between patients diagnosed with the same tumor type. Although in recent years significant technological advances have been made in the way radiation can be precisely delivered to tumors, it is proving more difficult to personalize radiotherapy regimens based on cancer biology. Biomarkers that provide prognostic or predictive information regarding a tumor's intrinsic radiosensitivity or its response to treatment could prove valuable in helping to personalize radiation dosing, enabling clinicians to make decisions between different treatment options whilst avoiding radiation-induced toxicity in patients unlikely to gain therapeutic benefit. Studies have investigated numerous ways in which both patient and tumor radiosensitivities can be assessed. Tumor molecular profiling has been used to develop radiosensitivity gene signatures, while the assessment of specific intracellular or secreted proteins, including circulating tumor cells, exosomes and DNA, has been performed to identify prognostic or predictive biomarkers of radiation response. Finally, the investigation of biomarkers related to radiation-induced toxicity could provide another means by which radiotherapy could become personalized. In this review, we discuss studies that have used these methods to identify or develop prognostic/predictive signatures of radiosensitivity, and how such assays could be used in the future as a means of providing personalized radiotherapy.

Effect of younger age on survival outcomes in T1N0M0 breast cancer: A propensity score matching analysis

PURPOSE

We evaluated the effect of younger age on recurrence risk in Chinese women diagnosed with T1N0M0 breast cancer (BC), using propensity score matching (PSM) analysis.

METHODS

We included 365 women who were diagnosed with T1N0M0 BC between 2003 and 2016, and who received surgery at our center. They were classified as younger (≤40 years) and older (>40 years). We used PSM to balance clinicopathologic characteristics between the two age groups. Survival was analyzed by the Kaplan-Meier method, before and after PSM.

RESULTS

Over a median follow-up period of 79 months, 54 patients developed recurrences. Before PSM, younger patients had worse recurrence-free survival (RFS) than older patients. Significantly worse RFS was seen in younger patients with HER2⁺ BC compared with their older counterparts. Younger patients had higher rates of locoregional recurrence rather than metastasis, especially in the first 5 years after diagnosis. After PSM, the two age groups still significantly differed in 5-year RFS.

CONCLUSION

Among PSM pairs with T1N0M0 BC, with equal baselines and treatment conditions, we found that patients who presented at younger ages had worse outcomes, independently of other pathological features. Younger patients with BC may require more individualized therapy to improve their prognosis.

Molecular determinants of post-mastectomy breast cancer recurrence

Breast cancer (BC) adjuvant therapy after mastectomy in the setting of 1-3 positive lymph nodes has been controversial. This retrospective Translational Breast Cancer Research Consortium study evaluated molecular aberrations in primary cancers associated with locoregional recurrence (LRR) or distant metastasis (DM) compared to non-recurrent controls. We identified 115 HER2 negative, therapy naïve, T 1-3 and N 0-1 BC patients treated with mastectomy but no post-mastectomy radiotherapy. This included 32 LRR, 34 DM, and 49 controls. RNAseq was performed on primary tumors in 110 patients; with no difference in RNA profiles between patients with LRR, DM, or controls. DNA analysis on 57 primary tumors (17 LRR, 15 DM, and 25 controls) identified significantly more NF1 mutations and mitogen-activated protein kinase (MAPK) pathway gene mutations in patients with LRR (24%, 47%) and DM (27%, 40%) compared to controls (0%, 0%; p < 0.0001 and p = 0.0070, respectively). Three patients had matched primary vs. LRR samples, one patient had a gain of a NF1 mutation in the LRR. There was no significant difference between the groups for PTEN loss or cleaved caspase 3 expression. The mean percentage Ki 67 labeling index was higher in patients with LRR (29.2%) and DM (26%) vs. controls (14%, p = 0.0045). In summary, mutations in the MAPK pathway, specifically NF1, were associated with both LRR and DM, suggesting that alterations in MAPK signaling are associated with a more aggressive tumor phenotype. Validation of these associations in tissues from randomized trials may support targeted therapy to reduce breast cancer recurrence.

Integrating Radiosensitivity and Immune Gene Signatures for Predicting Benefit of Radiotherapy in Breast Cancer

Purpose: Breast cancer is a heterogeneous disease and not all patients respond equally to adjuvant radiotherapy. Predictive biomarkers are needed to select patients who will benefit from the treatment and spare others the toxicity and burden of radiation.Experimental Design: We first trained and tested an intrinsic radiosensitivity gene signature to predict local recurrence after radiotherapy in three cohorts of 948 patients. Next, we developed an antigen processing and presentation-based immune signature by maximizing the treatment interaction effect in 129 patients. To test their predictive value, we matched patients treated with or without radiotherapy in an independent validation cohort for clinicopathologic factors including age, ER status, HER2 status, stage, hormone-therapy, chemotherapy, and surgery. Disease-specific survival (DSS) was the primary endpoint.Results: Our validation cohort consisted of 1,439 patients. After matching and stratification by the radiosensitivity signature, patients who received radiotherapy had better DSS than patients who did not in the radiation-sensitive group [hazard ratio (HR), 0.68; P = 0.059; n = 322], whereas a reverse trend was observed in the radiation-resistant group (HR, 1.53; P = 0.059; n = 202). Similarly, patients treated with radiotherapy had significantly better DSS in the immune-effective group (HR, 0.46; P = 0.0076; n = 180), with no difference in DSS in the immune-defective group (HR, 1.27; P = 0.16; n = 348). Both signatures were predictive of radiotherapy benefit (P _interaction = 0.007 and 0.005). Integration of radiosensitivity and immune signatures further stratified patients into three groups with differential outcomes for those treated with or without radiotherapy (P _interaction = 0.003).Conclusions: The proposed signatures have the potential to select patients who are most likely to benefit from radiotherapy. Clin Cancer Res; 24(19); 4754-62. ©2018 AACR.

Molecular Signatures of Radiation Response in Breast Cancer: Towards Personalized Decision-Making in Radiation Treatment

Recent advances in gene expression profiling have allowed for a more sophisticated understanding of the biology of breast cancers. These advances led to the development of molecular signatures that now allow clinicians to more individually tailor recommendations regarding the utility and necessity of systemic therapies for women with breast cancer. Indeed, these molecularly based tests have been incorporated into national and international best practice guidelines and are now part of routine practice. Similar, though slower, progress is being made in the development of molecular signatures predictive of radiation response and necessity for women with breast cancer. This article will discuss the history of radiation response signature development, the current state of these signatures under ongoing clinical development, the barriers to their clinical adoption, and upcoming changes and opportunities that may allow for the personalized radiation treatment recommendations enabled by the development of these signatures.

Response to Radiotherapy After Breast-Conserving Surgery in Different Breast Cancer Subtypes in the Swedish Breast Cancer Group 91 Radiotherapy Randomized Clinical Trial

Purpose To evaluate the effect of adjuvant radiotherapy (RT) after breast conservation surgery in different breast cancer subtypes in a large, randomized clinical trial with long-term follow-up. Patients and Methods Tumor tissue was collected from 1,003 patients with node-negative, stage I and II breast cancer who were randomly assigned in the Swedish Breast Cancer Group 91 Radiotherapy trial between 1991 and 1997 to breast conservation surgery with or without RT. Systemic adjuvant treatment was sparsely used (8%). Subtyping was performed with immunohistochemistry and in situ hybridization on tissue microarrays for 958 tumors. Results RT reduced the cumulative incidence of ipsilateral breast tumor recurrence (IBTR) as a first event within 10 years for luminal A-like tumors (19% v 9%; P = .001), luminal B-like tumors (24% v 8%; P < .001), and triple-negative tumors (21% v 6%; P = .08), but not for human epidermal growth factor receptor 2-positive (luminal and nonluminal) tumors (15% v 19%; P = .6); however, evidence of an overall difference in RT effect between subtypes was weak ( P = .21). RT reduced the rate of death from breast cancer (BCD) for triple-negative tumors (hazard ratio, 0.35; P = .06), but not for other subtypes. Death from any cause was not improved by RT in any subtype. A hypothesized clinical low-risk group did not have a low risk of IBTR without RT, and RT reduced the rate of IBTR as a first event after 10 years (20% v 6%; P = .008), but had no effect on BCD or death from any cause. Conclusion Subtype was not predictive of response to RT, although, in our study, human epidermal growth factor receptor 2-positive tumors seemed to be most radioresistant, whereas triple-negative tumors had the largest effect on BCD. The effect of RT in the presumed low-risk luminal A-like tumors was excellent.

How could breast cancer molecular features contribute to locoregional treatment decision making?

Systemic treatments are tailored to breast cancer (BC) heterogeneity, which is not yet taken into account for radiotherapy (RT) personalization. The primary objective of this review is to summarize existing data suggesting BC subtypes and genetic assays are prognostic and predictive biomarkers useful for RT decision-making and to provide implications for their incorporation into future translational and clinical research. The evidence suggesting that BC subtypes also exhibit distinct "locoregional recurrence (LRR)" patterns is retrospective but consistent and validated in over fifteen studies. The HER-2 positive and triple negative subtypes are the most susceptible to locoregional failure. The high risk of the HER-2 positive subtype can be reversed with trastuzumab administration. Very little is known on the subtypes' intrinsic radiosensitivity properties. Genetic assays have assessed retrospectively signatures' prognostic and predictive value in patients' cohorts (several coming from prospective studies) for LRR risk and radiotherapy (RT) benefit. Further confirmation is needed before their introduction into clinical routine. Evidence on the use of molecular biomarkers for adjuvant RT tailoring is emerging but needs validation and introduction into prospective studies. The plethora of modern RT options (partial breast irradiation, hypofractionation), as well as recent evidence pointing towards more extensive radiotherapy, demand introduction of biological features into clinical trials to improve therapeutic decisions. Open questions, such as tailoring of irradiation after neo-adjuvant chemotherapy in complete responders and the understanding of the interplay between local control, systemic recurrence and survival given modern systemic treatments, need to be addressed under the prism of biology within this heterogeneous disease. Intrinsic radiobiological properties within this heterogeneity need to be highlighted in order to further improve outcomes.

The changing landscape in radiotherapy for breast cancer: Lessons from long term follow-up in some European breast cancer trials

This review describes the developments in the radiation treatment of breast cancer based on some randomized European trials during the past decades. It will focus on the relevance of long term follow-up in breast cancer patients, starting with the surprising and important change in treatment results during follow-up shown in a locally advanced breast cancer trial. Breast conserving therapy (BCT) in stage I and II breast cancer was explored and tested in a randomized trial to prove equivalence between BCT and mastectomy. The positive outcome led to trials in breast conserving therapy with lower doses and partial breast irradiation. Finally the need for finding genetic profiles for predicting treatment response will be addressed in a trial with preoperative partial breast irradiation.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Over-irradiation

Decreasing the burden of radiation therapy (RT) for breast cancer includes, next to complete omission, several ways to tailor the extent of RT. Possible options for this include lowering of the total dose, such as selective omission of the boost, hypofractionated RT to shorten the duration of treatment, the selective introduction of partial breast irradiation and anatomy based target volume contouring to decrease the size of the irradiated volumes. Elective regional nodal irradiation showed in several randomised trials and meta-analyses to significantly impact on local-regional control, disease-free survival, breast cancer mortality and overall survival. The generalisability of these results remains complex in the light of the decreasing use of axillary lymph node dissection, the use of more effective adjuvant systemic therapy, the increasing use of primary systemic therapy and continuously improving RT techniques. In general, the use of RT compensates for the decreasing extent of surgery to the breast and the axillary lymph nodes, eliminating residual tumour cells while maintaining better aesthetic and functional results. In some occasions, however, the indications for the extent of RT have to be based on limited pathological staging information. Research is ongoing to individualise RT more on the basis of biological factors including gene expression profiles. When considering age, treatment decisions should rather be based on biological instead of formal age. The aim of this review article is to put current evidence into the right perspective, and to search for an appropriate appreciation of the balance between efficacy and side effects of local-regional RT.

MicroRNA-Related DNA Repair/Cell-Cycle Genes Independently Associated With Relapse After Radiation Therapy for Early Breast Cancer

PURPOSE

Local recurrence and distant failure after adjuvant radiation therapy for breast cancer remain significant clinical problems, incompletely predicted by conventional clinicopathologic markers. We had previously identified microRNA-139-5p and microRNA-1274a as key regulators of breast cancer radiation response in vitro. The purpose of this study was to investigate standard clinicopathologic markers of local recurrence in a contemporary series and to establish whether putative target genes of microRNAs involved in DNA repair and cell cycle control could better predict radiation therapy response in vivo.

METHODS AND MATERIALS

With institutional ethics board approval, local recurrence was measured in a contemporary, prospectively collected series of 458 patients treated with radiation therapy after breast-conserving surgery. Additionally, independent publicly available mRNA/microRNA microarray expression datasets totaling >1000 early-stage breast cancer patients, treated with adjuvant radiation therapy, with >10 years of follow-up, were analyzed. The expression of putative microRNA target biomarkers--TOP2A, POLQ, RAD54L, SKP2, PLK2, and RAG1--were correlated with standard clinicopathologic variables using 2-sided nonparametric tests, and to local/distant relapse and survival using Kaplan-Meier and Cox regression analysis.

RESULTS

We found a low rate of isolated local recurrence (1.95%) in our modern series, and that few clinicopathologic variables (such as lymphovascular invasion) were significantly predictive. In multiple independent datasets (n>1000), however, high expression of RAD54L, TOP2A, POLQ, and SKP2 significantly correlated with local recurrence, survival, or both in univariate and multivariate analyses (P<.001). Low RAG1 expression significantly correlated with local recurrence (multivariate, P=.008). Additionally, RAD54L, SKP2, and PLK2 may be predictive, being prognostic in radiation therapy-treated patients but not in untreated matched control individuals (n=107; P<.05).

CONCLUSIONS

Biomarkers of DNA repair and cell cycle control can identify patients at high risk of treatment failure in those receiving radiation therapy for early breast cancer in independent cohorts. These should be further investigated prospectively, especially TOP2A and SKP2, for which targeted therapies are available.

Technical innovation in adjuvant radiotherapy: Evolution and evaluation of new treatments for today and tomorrow

Recent innovations in breast cancer radiotherapy include intensity modulated radiotherapy, brachytherapy and intraoperative radiotherapy and current trials are seeking to evaluate their value in optimizing local control while maintaining cosmetic effects. Future clinical dividends in local control and survival may come from the identification of molecular signatures of breast cancer radiosensitivity, the development of predictive signatures and identification of immunohistochemical markers of risk of local recurrence. The importance of tumour heterogeneity is being increasingly recognized as an important factor in determining radiotherapy response and an improved understanding of the biology of the tumour microenvironment may identify targets that allow enhanced radiosensitisation or reversal of radioresistance when inhibited. This review describes recent developments in these areas.

DEGRO practical guidelines for radiotherapy of breast cancer V: Therapy for locally advanced and inflammatory breast cancer, as well as local therapy in cases with synchronous distant metastases

AIM

The purpose of this work is to give practical guidelines for radiotherapy of locally advanced, inflammatory and metastatic breast cancer at first presentation.

METHODS

A comprehensive survey of the literature using the search phrases "locally advanced breast cancer", "inflammatory breast cancer", "breast cancer and synchronous metastases", "de novo stage IV and breast cancer", and "metastatic breast cancer" and "at first presentation" restricted to "clinical trials", "randomized trials", "meta-analysis", "systematic review", and "guideline" was performed and supplemented by using references of the respective publications. Based on the German interdisciplinary S3 guidelines, updated in 2012, this publication addresses indications, sequence to other therapies, target volumes, dose, and fractionation of radiotherapy.

RESULTS

International and national guidelines are in agreement that locally advanced, at least if regarded primarily unresectable and inflammatory breast cancer should receive neoadjuvant systemic therapy first, followed by surgery and radiotherapy. If surgery is not amenable after systemic therapy, radiotherapy is the treatment of choice followed by surgery, if possible. Surgery and radiotherapy should be administered independent of response to neoadjuvant systemic treatment. In patients with a de novo diagnosis of breast cancer with synchronous distant metastases, surgery and radiotherapy result in considerably better locoregional tumor control. An improvement in survival has not been consistently proven, but may exist in subgroups of patients.

CONCLUSION

Radiotherapy is an important part in the treatment of locally advanced and inflammatory breast cancer that should be given to all patients regardless to the intensity and effect of neoadjuvant systemic treatment and the extent of surgery. Locoregional radiotherapy in patients with primarily distant metastatic disease should be prescribed on an individual basis.

The 21-gene recurrence score and locoregional recurrence in breast cancer patients

PURPOSE

Although the 21-gene recurrence score (RS) assay has been validated to assess the risk of distant recurrence in hormone receptor-positive breast cancer patients, the relationship between RS and the risk of locoregional recurrence (LRR) remains unclear. The purpose of this study was to determine if RS is associated with LRR in breast cancer patients and whether this relationship varies based on the type of local treatment [mastectomy or breast-conserving therapy (BCT)].

METHODS

163 consecutive estrogen receptor-positive breast cancer patients at our institution had an RS generated from the primary breast tumor between August 2006 and October 2009. Patients were treated with lumpectomy and radiation (BCT) (n = 110) or mastectomy alone (n = 53). Patients were stratified using a pre-determined RS of 25 and then grouped according to local therapy type.

RESULTS

Median follow-up was 68.2 months. Patients who developed an LRR had stage I or IIA disease, >2 mm surgical margins, and received chemotherapy as directed by RS. While an RS > 25 did not predict for a higher rate of LRR, an RS > 24 was associated with LRR in our subjects. Among mastectomy patients, the 5-year LRR rate was 27.3 % in patients with an RS > 24 versus 10.7 % (p = 0.04) in those whose RS was ≤ 24. RS was not associated with LRR in patients who received BCT.

CONCLUSIONS

Breast cancer patients treated with mastectomy for tumors that have an RS > 24 are at high risk of LRR and may benefit from post-mastectomy radiation.

The genomic expression test EndoPredict is a prognostic tool for identifying risk of local recurrence in postmenopausal endocrine receptor-positive, her2neu-negative breast cancer patients randomised within the prospective ABCSG 8 trial

Background:

The aim of this study was to examine whether EndoPredict (EP), a novel genomic expression test, is effective in predicting local recurrence (LR)-free survival (LRFS) following surgery for breast cancer in postmenopausal women. In addition, we examined whether EP may help tailor local therapy in these patients.

Methods:

From January 1996 to June 2004, 3714 postmenopausal patients were randomly assigned to either tamoxifen or tamoxifen followed by anastrozole within the prospective ABCSG 8 trial. Using assay scores from EP, we classified breast tumour blocks as either low or high risk for recurrence.

Results:

Data were gathered from 1324 patients. The median follow-up was 72.3 months and the cumulative incidence of LR was 2.6% (0.4% per year). The risk of LR over a 10-year period among patients with high-risk lesions (n=683) was significantly higher (LRFS=91%) when compared with patients with low-risk lesions (n=641) (10-year LRFS=97.5%) (HR: 1.31 (1.16–1.48) P<0.005). The groups that received breast conservation surgery (BCT) and mastectomy (MX) had similar LR rates (P=0.879). Radiotherapy (RT) after BCT significantly improved LRFS in the cohorts predicted by EP to be low-risk for LR (received RT: n=436, 10-year LRFS 99.8% did not receive RT: n=63, 10-year LRFS 83.6%, P<0.005).

Conclusions:

EndoPredict is an effective prognostic tool for predicting LRFS. Among postmenopausal, low-risk patients, EP does not appear to be useful for tailoring local therapy.

Development and validation of a gene profile predicting benefit of postmastectomy radiotherapy in patients with high-risk breast cancer: a study of gene expression in the DBCG82bc cohort

PURPOSE

To identify genes predicting benefit of radiotherapy in patients with high-risk breast cancer treated with systemic therapy and randomized to receive or not receive postmastectomy radiotherapy (PMRT).

EXPERIMENTAL DESIGN

The study was based on the Danish Breast Cancer Cooperative Group (DBCG82bc) cohort. Gene-expression analysis was performed in a training set of frozen tumor tissue from 191 patients. Genes were identified through the Lasso method with the endpoint being locoregional recurrence (LRR). A weighted gene-expression index (DBCG-RT profile) was calculated and transferred to quantitative real-time PCR (qRT-PCR) in corresponding formalin-fixed, paraffin-embedded (FFPE) samples, before validation in FFPE from 112 additional patients.

RESULTS

Seven genes were identified, and the derived DBCG-RT profile divided the 191 patients into "high LRR risk" and "low LRR risk" groups. PMRT significantly reduced risk of LRR in "high LRR risk" patients, whereas "low LRR risk" patients showed no additional reduction in LRR rate. Technical transfer of the DBCG-RT profile to FFPE/qRT-PCR was successful, and the predictive impact was successfully validated in another 112 patients.

CONCLUSIONS

A DBCG-RT gene profile was identified and validated, identifying patients with very low risk of LRR and no benefit from PMRT. The profile may provide a method to individualize treatment with PMRT.

Invasive lobular breast cancer and its variants: how special are they for systemic therapy decisions?

The WHO classification of breast tumors distinguishes, besides invasive breast cancer 'of no special type' (former invasive ductal carcinoma, representing 60-70% of all breast cancers), 30 special types, of which invasive lobular carcinoma (ILC) is the most common (5-15%). We review the literature on (i) the specificity and heterogeneity of ILC biology as documented by various analytical techniques, including the results of molecular testing for risk of recurrence; (ii) the impact of lobular histology on prediction of prognosis and effect of systemic therapies in patients. Though it is generally admitted that ILC has a better prognosis than IDC, is endocrine responsive, and responds poorly to chemotherapy, currently available data do not unanimously support these assumptions. This review demonstrates some lack of specific data and a need for improving clinical research design to allow oncologists to make informed systemic therapy decisions in patients with ILC. Importantly, future studies should compare various endpoints in ILC breast cancer patients among the group of hormonosensitive breast cancer.

Co-overexpression of GEP100 and AMAP1 proteins correlates with rapid local recurrence after breast conservative therapy

A major problem of current cancer research and therapy is prediction of tumor recurrence after initial treatment, rather than the simple biological characterization of the malignancy and proliferative properties of tumors. Breast conservation therapy (BCT) is a well-approved, standard treatment for patients with early stages of breast cancer, which consists of lumpectomy and whole-breast irradiation. In spite of extensive studies, only 'age' and 'Ki-67 positivity' have been identified to be well correlated with local recurrence after BCT. An Arf6 pathway, activated by GEP100 under receptor tyrosine kinases (RTKs) and employs AMAP1 as its effector, is crucial for invasion and metastasis of some breast cancer cells. This pathway activates β1 integrins and perturbs E-cadherin-based adhesions, hence appears to be integral for epithelial-mesenchymal transdifferentiation (EMT). We here show that expression of the Arf6 pathway components statistically correlates with rapid local recurrence after BCT. We retrospectively analyzed four hundred seventy-nine patients who received BCT in Hokkaido University Hospital, and found 20 patients had local recurrence. We then analyzed pathological samples of patients who experienced local recurrence by use of Kaplan-Meier analysis, Stepwise regression analysis and the t-test, coupled with immunostaining, and found that co-overexpression of GEP100 and AMAP1 correlates with rapidity of the local recurrence. Their margin-status, node-positivity, and estrogen receptor (ER)- or progesterone receptor (PgR)-positivity did not correlated with the rapidity. This study is the first to show that expression of a certain set of proteins correlates with the rapidity of local recurrence. Our results are useful not only for prediction, but highlight the possibility of developing novel strategies to block local recurrence. We also discuss why mRNAs encoding these proteins have not been identified to correlate with local recurrence by previous conventional gene expression profiling analyses.

Local recurrence following breast-conserving treatment in women aged 40 years or younger: trends in risk and the impact on prognosis in a population-based cohort of 1143 patients

AIM

To evaluate trends in the risk of local recurrences after breast-conserving treatment (BCT) and to examine the impact of local recurrence (LR) on distant relapse-free survival in a large, population-based cohort of women aged ≤40 years with early-stage breast cancer.

METHODS

All women (n=1143) aged ≤40 years with early-stage (pT1-2/cT1-2, N0-2, M0) breast cancer who underwent BCT in the south of the Netherlands between 1988 and 2010 were included. BCT consisted of local excision of the tumour followed by irradiation of the breast.

RESULTS

After a median follow-up of 8.5 (0.1-24.6)years, 176 patients had developed an isolated LR. The 5-year LR-rate for the subgroups treated in the periods 1988-1998, 1999-2005 and 2006-2010 were 9.8% (95% confidence interval (CI) 7.1-12.5), 5.9% (95% CI 3.2-8.6) and 3.3% (95% CI 0.6-6.0), respectively (p=0.006). In a multivariate analysis, adjuvant systemic treatment was associated with a reduced risk of LR of almost 60% (hazard ratio (HR) 0.42; 95%CI 0.28-0.60; p<0.0001). Patients who experienced an early isolated LR (≤5 years after BCT) had a worse distant relapse-free survival compared to patients without an early LR (HR 1.83; 95% CI 1.27-2.64; p=0.001). Late local recurrences did not negatively affect distant relapse-free survival (HR 1.24; 95% CI 0.74-2.08; p=0.407).

CONCLUSION

Local control after BCT improved significantly over time and appeared to be closely related to the increased use and effectiveness of systemic therapy. These recent results underline the safety of BCT for young women with early-stage breast cancer.

Risk stratification in ductal carcinoma in situ: the role of genomic testing

From the earliest days of conservative surgery for ductal carcinoma in situ (DCIS) of the breast, there have been attempts to identify patients who may not need postoperative radiation. Randomized prospective trials have not identified a population for whom there is no benefit to radiation. However, decades of studies of clinical, radiological and pathologic correlates to local recurrence have led to criteria for a patient subgroup at low risk for local recurrence after omission of radiation. Gene expression profiling for invasive breast cancer has been used to identify patients at low, intermediate or high risk for distant recurrence. Application of this methodology to DCIS aims to identify patients at low, intermediate or high risk for local recurrence. Whether this method of risk stratification will prove more accurate than clinical, radiological and pathologic risk stratification, or identify patients with little to no clinical benefit from radiation, remains to be seen.

Long-term prognostic performance of Ki67 rate in early stage, pT1-pT2, pN0, invasive breast carcinoma

BACKGROUND

Molecular signatures may become of use in clinical practice to assess the prognosis of breast cancers. However, although international consensus conferences sustain the use of these new markers in the near future, concerns remain about their degree of discordance and cost-effectiveness in different international settings. The present study aims to validate Ki67 as prognostic factor in a large cohort of early-stage (pT1-pT2, pN0) breast cancer patients.

METHODS

456 patients treated in 1995-1996 were identified in the Institut Curie database. Ki67 (MIB1) was retrospectively assessed by immunohistochemistry for all cases. The prognostic value of this index was compared to that of histological grade (HG), Estrogen receptor (ER) and HER2 status. Distant disease free interval, loco-regional recurrence, time-lapse from first metastatic diagnosis to death were analyzed.

RESULTS

All 456 patients were treated by lumpectomy plus axillary dissection and radiotherapy. 27 patients (5.9%) received systemic treatment. Tumors were classified as HG1 in 35%, HG2 in 42% and HG3 in 23% of cases. ER was expressed in 86% of the tumors, HER2 in 5% and 14% were triple negative. The median follow-up was 151 [5-191] months. Distant and loco-regional disease recurrences were observed in 16% and 18%, respectively. High (>20%) Ki67 rate [HR = 3 (1.8-4.8), p<10e-06] and HG3 [HR = 4.4 (2.2-8.6), p = 0.00002] were associated with an increased rate of distant relapse. In multivariate analysis, the Ki67 remained the only significant prognostic factor in the subgroups of ER positive HER2 negative [HR = 2.6 (1.5-4.6), p = 0.0006] and ER positive HER2 negative HG2 tumors [HR = 2.2 (1.01-4.8), p = 0.04].

CONCLUSIONS

We validate the prognosis value of the Ki67 rate in small size node negative breast cancer. We conclude that Ki67 is a potential cost-effective decision marker for adjuvant therapy in early-stage HG2, pT1-pT2, pN0, breast cancers.

Accelerated partial breast irradiation: the need for well-defined patient selection criteria, improved volume definitions, close follow-up and discussion of salvage treatment

Breast-conserving therapy, including whole breast irradiation, has become a well-established alternative to mastectomy in early-stage breast cancer patients, with similar survival rates and better cosmetic outcome. However, many women are still treated with mastectomy, due to logistical issues related to the long course of radiotherapy (RT). To reduce mastectomy rates and/or omission of RT after breast-conserving surgery, shorter, hypofractionated RT treatments have been introduced. More recently, the necessity of routinely treating the entire breast in all patients has been questioned, leading to the development of partial breast radiotherapy. With accelerated partial breast irradiation (APBI) these two approaches have been combined: the tumor bed with a 1-2 cm margin is irradiated either intra-operatively (single fraction) or postoperatively over 5-15 days. Different techniques have been developed, including interstitial brachytherapy, intra-cavity brachytherapy, intra-operative radiotherapy and external beam radiotherapy. These techniques are being evaluated in several ongoing phase III studies. Since its introduction, APBI has been the subject of continuous debate. ASTRO and GEC-ESTRO have published guidelines for patient selection for APBI, and strongly recommend that APBI be carried out within ongoing clinical trials. Recently, the patient selection criteria for APBI have also been up for debate, following the publication of results from different groups that do/do not confirm a difference in recurrence risk among the ASTRO defined risk groups. This paper reviews the different APBI techniques, current recommendations for patient selection, available clinical data and ongoing clinical trials. A case report is included to illustrate the need for careful follow-up of patients treated with APBI.

Radiation therapy after breast-conserving surgery

SUMMARY Whole-breast irradiation in combination with breast-conserving surgery is a recognized standard alternative to mastectomy for the local treatment of early breast cancer. This article will review the evidence on the relationship of local control in the treated breast and survival, the indications of a boost dose to the tumor bed and the need for breast irradiation in ductal carcinoma in situ. Novel, shorter fractionation schemes allow the constraints of daily treatment courses over several weeks to be reduced, and recent technical improvements in treatment delivery will improve the results of treatment – in terms of local control and reduction of toxicity, and long-term sequelae. Research should focus on identifying molecular markers of radiation sensitivity and designing specific, targeted modulators of the radiation response in breast cancer.

Validation of a radiosensitivity molecular signature in breast cancer

PURPOSE

Previously, we developed a radiosensitivity molecular signature [radiosensitivity index (RSI)] that was clinically validated in 3 independent datasets (rectal, esophageal, and head and neck) in 118 patients. Here, we test RSI in radiotherapy (RT)-treated breast cancer patients.

EXPERIMENTAL DESIGN

RSI was tested in 2 previously published breast cancer datasets. Patients were treated at the Karolinska University Hospital (n = 159) and Erasmus Medical Center (n = 344). RSI was applied as previously described.

RESULTS

We tested RSI in RT-treated patients (Karolinska). Patients predicted to be radiosensitive (RS) had an improved 5-year relapse-free survival when compared with radioresistant (RR) patients (95% vs. 75%, P = 0.0212), but there was no difference between RS/RR patients treated without RT (71% vs. 77%, P = 0.6744), consistent with RSI being RT-specific (interaction term RSI × RT, P = 0.05). Similarly, in the Erasmus dataset, RT-treated RS patients had an improved 5-year distant metastasis-free survival over RR patients (77% vs. 64%, P = 0.0409), but no difference was observed in patients treated without RT (RS vs. RR, 80% vs. 81%, P = 0.9425). Multivariable analysis showed RSI is the strongest variable in RT-treated patients (Karolinska, HR = 5.53, P = 0.0987, Erasmus, HR = 1.64, P = 0.0758) and in backward selection (removal α of 0.10), RSI was the only variable remaining in the final model. Finally, RSI is an independent predictor of outcome in RT-treated ER(+) patients (Erasmus, multivariable analysis, HR = 2.64, P = 0.0085).

CONCLUSIONS

RSI is validated in 2 independent breast cancer datasets totaling 503 patients. Including prior data, RSI is validated in 5 independent cohorts (621 patients) and represents, to our knowledge, the most extensively validated molecular signature in radiation oncology.

Predictive factors for local recurrence in breast cancer

Risk factors for local recurrence in breast cancer after breast conserving therapy (BCT) differ from those for local recurrence after mastectomy. To better guide optimal treatment of individual patients, it is desirable to identify patients at high risk for local recurrence. Several clinical and histopathologic factors, such as young age and presence of ductal carcinoma in situ, are known to be predictors for local recurrence after BCT. After mastectomy, lymph node status and tumor size are dominant risk factors for local recurrence. The results of recent expression profiling studies have explained differences in prognosis and risk for local recurrence and also explained response to different therapies (adjuvant systemic therapy and radiotherapy). Because of the variation in different subtypes of breast cancer and the difference in amount of tumor burden remaining after surgery, finding robust predictive profiles is complex. In this review, we describe the predictive and prognostic factors for local recurrence after mastectomy and BCT and also describe the role of radiosensitivity in local recurrence.

The challenge of gene expression profiling in heterogeneous clinical samples

Almost all samples used in tumor biology, such as tissues and bodily fluids, are heterogeneous, i.e., consist of different cell types. Evaluating the degree of heterogeneity in samples can increase our knowledge on processes such as clonal selection and metastasis. In addition, generating expression profiles from specific sub populations of cells can reveal their distinct functions. Tissue heterogeneity also poses a challenge, as it can confound the interpretation of gene expression data. This chapter will (1) give a brief overview on how heterogeneity may influence gene expression profiling data and (2) describe the methods that are currently available to assess transcriptional biomarkers in a heterogeneous cell population.

Prognostic value of biologic subtype and the 21-gene recurrence score relative to local recurrence after breast conservation treatment with radiation for early stage breast carcinoma: results from the Eastern Cooperative Oncology Group E2197 study

The present study was performed to evaluate the significance of biologic subtype and 21-gene recurrence score relative to local recurrence and local-regional recurrence after breast conservation treatment with radiation. Eastern Cooperative Oncology Group E2197 was a prospective randomized clinical trial that compared two adjuvant systemic chemotherapy regimens for patients with operable breast carcinoma with 1-3 positive lymph nodes or negative lymph nodes with tumor size >1.0 cm. The study population was a subset of 388 patients with known 21-gene recurrence score and treated with breast conservation surgery, systemic chemotherapy, and definitive radiation treatment. Median follow-up was 9.7 years (range = 3.7-11.6 years). The 10-year rates of local recurrence and local-regional recurrence were 5.4 % and 6.6 %, respectively. Neither biologic subtype nor 21-gene Recurrence Score was associated with local recurrence or local-regional recurrence on univariate or multivariate analyses (all P ≥ 0.12). The 10-year rates of local recurrence were 4.9 % for hormone receptor positive, HER2-negative tumors, 6.0 % for triple negative tumors, and 6.4 % for HER2-positive tumors (P = 0.76), and the 10-year rates of local-regional recurrence were 6.3, 6.9, and 7.2 %, respectively (P = 0.79). For hormone receptor-positive tumors, the 10-year rates of local recurrence were 3.2, 2.9, and 10.1 % for low, intermediate, and high 21-gene recurrence score, respectively (P = 0.17), and the 10-year rates of local-regional recurrence were 3.8, 5.1, and 12.0 %, respectively (P = 0.12). For hormone receptor-positive tumors, the 21-gene recurrence score evaluated as a continuous variable was significant for local-regional recurrence (hazard ratio 2.66; P = 0.03). The 10-year rates of local recurrence and local-regional recurrence were reasonably low in all subsets of patients. Neither biologic subtype nor 21-gene recurrence score should preclude breast conservation treatment with radiation.

Locoregional recurrence after breast-conserving therapy remains an independent prognostic factor even after an event free interval of 10 years in early stage breast cancer

INTRODUCTION

Locoregional recurrence (LRR) after breast-conserving therapy is a well-known independent risk factor associated with unfavourable long-term outcome. Controversy exists concerning the prognostic impact of a LRR after a very long event-free interval.

METHOD

Patients who underwent breast-conserving therapy for early stage breast cancer were pooled from four European Organisation for Research and Treatment of Cancer (EORTC) Breast Group trials. Only LRR as a first event was taken into account. Risk factors such as tumour size, nodal status, young age and chemotherapy were assessed in multivariate Cox regression analysis. LRR was used as a time-dependent variable in the landmark analysis for distant disease-free survival (DFS) and overall survival (OS). Patients were categorised as having at least 0, 5 or 10 years event-free survival.

RESULTS

In total, 7751 early stage breast cancer patients were included with a median follow-up of 10.9 years. Tumour size, nodal status, young age and chemotherapy are strong independent prognostic factors with a significant impact on long-term outcome, but lose their power and significance over time. Including all patients, LRR was the strongest prognostic factor for OS and distant DFS (resp. HR 5.01 and HR 5.31, p<0.001). In the subgroup of patients developing a LRR after at least 5 or 10 years, LRR remained the strongest independent prognostic factor for OS (resp. HR 3.98, HR 4.96, p ≤ 0.001) and distant DFS (HR 4.42, HR 7.57 p<0.001).

CONCLUSION

This is the first study which shows LRR after breast-conserving therapy is a very strong, time-independent prognostic factor for long term outcome in early stage breast cancer patients. These findings suggest that a LRR after a long event-free interval seems to be an indicator rather than an instigator of subsequent distant disease.

Breast conserving therapy versus mastectomy for stage I-II breast cancer: 20 year follow-up of the EORTC 10801 phase 3 randomised trial

BACKGROUND

The EORTC 10801 trial compared breast-conserving therapy (BCT) with modified radical mastectomy (MRM) in patients with tumours 5 cm or smaller and axillary node negative or positive disease. Compared with BCT, MRM resulted in better local control, but did not affect overall survival or time to distant metastases. We report 20-year follow-up results.

METHODS

The EORTC 10801 trial was open for accrual between 1980 and 1986 in eight centres in the UK, the Netherlands, Belgium, and South Africa. 448 patients were randomised to BCT and 420 to MRM. Randomisation was done centrally, stratifying patients by institute, carcinoma stage (I or II), and menopausal status. BCT comprised of lumpectomy and complete axillary clearance, followed by breast radiotherapy and a tumour-bed boost. The primary endpoint was time to distant metastasis. This analysis was done on all eligible patients, as they were randomised.

FINDINGS

After a median follow-up of 22·1 years (IQR 18·5-23·8), 175 patients (42%) had distant metastases in the MRM group versus 207 (46%) in the BCT group. Furthermore, 506 patients (58%) died (232 [55%] in the MRM group and 274 [61%] in the BCT group). No significant difference was observed between BCT and MRM for time to distant metastases (hazard ratio 1·13, 95% CI 0·92-1·38; p=0·23) or for time to death (1·11, 0·94-1·33; 0·23). Cumulative incidence of distant metastases at 20 years was 42·6% (95% CI 37·8-47·5) in the MRM group and 46·9% (42·2-51·6) in the BCT group. 20-year overall survival was estimated to be 44·5% (95% CI 39·3-49·5) in the MRM group and 39·1% (34·4-43·9) in the BCT group. There was no difference between the groups in time to distant metastases or overall survival by age (time to distant metastases: <50 years 1·09 [95% CI 0·79-1·51] vs ≥50 years 1·16 [0·90-1·50]; overall survival <50 years 1·17 [0·86-1·59] vs ≥50 years 1·10 [0·89-1·37]).

INTERPRETATION

BCT, including radiotherapy, offered as standard care to patients with early breast cancer seems to be justified, since long-term follow-up in this trial showed similar survival to that after mastectomy.

FUNDING

European Organisation for Research and Treatment of Cancer (EORTC).