Partial-breast radiotherapy after breast conservation surgery for patients with early breast cancer (UK IMPORT LOW trial): 5-year results from a multicentre, randomised, controlled, phase 3, non-inferiority trial

Surgery for Good Prognosis Breast Cancers

Purpose of Review

The introduction of mammographic screening programmes has resulted increasing numbers of women with small breast cancers with biologically favourable characteristics. Many of these cancers may represent overdiagnosis, with a resulting treatment burden for women and healthcare costs for providers. Here, current surgical approaches to the treatment of such tumours are reviewed, together with alternative approaches to their management.

Recent Findings

The surgical treatment of small, screen-detected breast cancers with biologically favourable characteristics has been extrapolated from the management of symptomatic breast cancers. There is no prospective randomised evidence for conventional open surgery compared with other approaches in this setting. A number of minimally invasive techniques, most notable vacuum-assisted excision, have been described for the management of these tumours, but at present, there is a lack of high-quality evidence to support their routine use. There are currently ongoing randomised trials evaluating risk-adapted surgical and minimally invasive approaches to the management of good prognosis disease.

Summary

It is possible that the surgical treatment of good prognosis screen-detected breast cancers may be de-escalated. However, high-quality evidence from ongoing prospective randomised trials will be required in order to change clinical practice.

Long-term results of a randomized partial irradiation trial compared to whole breast irradiation in the early stage and low-risk breast cancer patients after conservative surgery

PURPOSE

To report long-term results of a randomized trial comparing accelerated partial breast irradiation (APBI) to whole-breast irradiation (WBI) in terms of efficacy, toxicity, and cosmesis.

METHODS AND MATERIALS

WBI group was treated with 3D conformal external irradiation, 2 Gy daily/fraction, 5 fractions/week, to a total dose of 50 Gy. APBI group was treated with 3D conformal external irradiation 3.75 Gy/fraction, twice a day, 5 fractions/week, to a total dose of 37.5 Gy in the APBI group. Patients were followed up every 6 months up to 5 years and yearly thereafter. During follow-up visits, the clinician evaluated chronic toxicity and scored cosmetic results with a four-scale system.

RESULTS

After a median follow-up of 10.3 years, 43 patients in each group (84%) are alive without disease. One patient died after disease progression in the APBI arm, and there was no death in the WBI arm. The rest of the patients died from another disease different than breast cancer, similarly between groups. There was greater fibrosis in the APBI group (9 patients grade 1 and one grade 2) compared to WBI (3 patients grade 1 and one grade 2); p = 0.18. Regarding cosmesis, in APBI group, 19 and 21 (43.2 and 47%) patients had excellent or good results, similar to the WBI group with 18 patients (40.9%) in each cosmesis outcome. The WBI group did not have any patient with poor cosmesis but the APBI had 3 (6.8%; p = 0.24).

CONCLUSION

After a follow-up of 10 years, there were no differences in efficacy between the 2 treatment arms. Despite slight greater toxicity in the APBI group, the cosmesis was similar and satisfactory in both groups.

IOERT versus external beam electrons for boost radiotherapy in stage I/II breast cancer: 10-year results of a phase III randomized study

Background

Intraoperative radiotherapy with electrons (IOERT) boost could be not inferior to external beam radiotherapy (EBRT) boost in terms of local control and tissue tolerance. The aim of the study is to present the long-term follow-up results on local control, esthetic evaluation, and toxicity of a prospective study on early-stage breast cancer patients treated with breast-conserving surgery with an IOERT boost of 10 Gy (experimental group) versus 5 × 2 Gy EBRT boost (standard arm). Both arms received whole-breast irradiation (WBI) with 50 Gy (2 Gy single dose).

Methods

A single-institution phase III randomized study to compare IOERT versus EBRT boost in early-stage breast cancer was conducted as a non-inferiority trial. Primary endpoints were the evaluation of in-breast true recurrences (IBTR) and out-field local recurrences (LR) as well as toxicity and cosmetic results. Secondary endpoints were overall survival (OS), disease-free survival (DFS), and patient’s grade of satisfaction with cosmetic outcomes.

Results

Between 1999 and 2004, 245 patients were randomized: 133 for IOERT and 112 for EBRT. The median follow-up was 12 years (range 10–16 years). The cumulative risk of IBTR at 5–10 years was 0.8% and 4.3% after IOERT, compared to 4.2% and 5.3% after EBRT boost (p = 0.709). The cumulative risk of out-field LR at 5–10 years was 4.7% and 7.9% for IOERT versus 5.2% and 10.3% for EBRT (p = 0.762). All of the IOERT arm recurrences were observed at > 100 months’ follow-up, whereas the mean time to recurrence in the EBRT group was earlier (55.2 months) (p < 0.05). No late complications associated with IOERT were observed. The overall cosmetic results were scored as good or excellent in physician and patient evaluations for both IOERT and EBRT. There were significantly better scores for IOERT at all time points in physician and patient evaluations with the greatest difference at the end of EBRT (p = 0.006 objective and p = 0.0004 subjective) and most narrow difference at 12 months after the end of EBRT (p = 0.08 objective and p = 0.04 subjective analysis).

Conclusion

A 10-Gy IOERT boost during breast-conserving surgery provides high local control rates without significant morbidity. Although not significantly superior to external beam boosts, the median time to local recurrences after IOERT is prolonged by more than 4 years.

Intraoperative irradiation for early breast cancer (ELIOT): long-term recurrence and survival outcomes from a single-centre, randomised, phase 3 equivalence trial

BACKGROUND

In the randomised, phase 3 equivalence trial on electron intraoperative radiotherapy (ELIOT), accelerated partial breast irradiation (APBI) with the use of intraoperative radiotherapy was associated with a higher rate of ipsilateral breast tumour recurrence (IBTR) than whole-breast irradiation (WBI) in patients with early-stage breast cancer. Here, we aimed to examine the planned long-term recurrence and survival outcomes from the ELIOT trial.

METHODS

This single-centre, randomised, phase 3 equivalence trial was done at the European Institute of Oncology (Milan, Italy). Eligible women, aged 48-75 years with a clinical diagnosis of a unicentric breast carcinoma with an ultrasound diameter not exceeding 25 mm, clinically negative axillary lymph nodes, and who were suitable for breast-conserving surgery, were randomly assigned (1:1) via a web-based system, with a random permuted block design (block size of 16) and stratified by clinical tumour size, to receive post-operative WBI with conventional fractionation (50 Gy given as 25 fractions of 2 Gy, plus a 10 Gy boost), or 21 Gy intraoperative radiotherapy with electrons (ELIOT) in a single dose to the tumour bed during surgery. The trial was open label and no-one was masked to treatment group assignment. The primary endpoint was the occurrence of IBTR. The trial was designed assuming a 5-year IBTR rate of 3% in the WBI group and equivalence of the two groups, if the 5-year IBTR rate in the ELIOT group did not exceed a 2·5 times excess, corresponding to 7·5%. Overall survival was the secondary endpoint. The main analysis was done by intention to treat. The cumulative incidence of IBTR events and overall survival were assessed at 5, 10, and 15 years of follow-up. This trial is registered with ClinicalTrials.gov, NCT01849133.

FINDINGS

Between Nov 20, 2000, and Dec 27, 2007, 1305 women were enrolled and randomly assigned: 654 to the WBI group and 651 to the ELIOT group. After a median follow-up of 12·4 years (IQR 9·7-14·7), 86 (7%) patients developed IBTR, with 70 (11%) cases in the ELIOT group and 16 (2%) in the WBI group, corresponding to an absolute excess of 54 IBTRs in the ELIOT group (HR 4·62, 95% CI 2·68-7·95, p<0·0001). In the ELIOT group, the 5-year IBTR rate was 4·2% (95% CI 2·8-5·9), the 10-year rate was 8·1% (6·1-10·3), and the 15-year rate was 12·6% (9·8-15·9). In the WBI group, the 5-year IBTR rate was 0·5% (95% CI 0·1-1·3), the 10-year rate was 1·1% (0·5-2·2), and the 15-year rate was 2·4% (1·4-4·0). At final follow-up on March 11, 2019, 193 (15%) women had died from any cause, with no difference between the two groups (98 deaths in the ELIOT group vs 95 in the WBI group; HR 1·03, 95% CI 0·77-1·36, p=0·85). In the ELIOT group, the overall survival rate was 96·8% (95% CI 95·1-97·9) at 5 years, 90·7% (88·2-92·7) at 10 years, and 83·4% (79·7-86·4) at 15 years; and in the WBI group, the overall survival rate was 96·8% (95·1-97·9) at 5 years, 92·7% (90·4-94·4) at 10 years, and 82·4% (78·5-85·6) at 15 years. We did not collect long-term data on adverse events.

INTERPRETATION

The long-term results of this trial confirmed the higher rate of IBTR in the ELIOT group than in the WBI group, without any differences in overall survival. ELIOT should be offered to selected patients at low-risk of IBTR.

FUNDING

Italian Association for Cancer Research, Jacqueline Seroussi Memorial Foundation for Cancer Research, Umberto Veronesi Foundation, American Italian Cancer Foundation, The Lombardy Region, and Italian Ministry of Health.

The Role of Intraoperative Radiation in Early-stage Breast Cancer

Intraoperative radiation therapy (IORT) is a specialized form of accelerated partial breast irradiation in which a single dose of radiation is delivered to the tumor bed at the time of breast conserving surgery. With completion of radiation to the tumor bed at the time of surgery, IORT promises improved patient convenience, compliance, and quality of life. In addition, with its potentially skin-sparing properties and ability to deliver a high biologically effective dose to the tumor bed while reducing dose to nontarget tissues, IORT results in different but overall less toxicities compared with other modalities of radiation for breast cancer. However, skepticism over the role of IORT in breast cancer exists, and the 2 randomized trials that have analyzed IORT as the definitive radiation component of breast conservation therapy have shown an increase in local recurrence rates with IORT compared with whole breast irradiation, but similar rates of overall survival. In this review, we discuss the practicalities of IORT, the prospective data supporting and negating the role of IORT in lieu of whole breast irradiation, and the toxicity after IORT in early-stage breast cancer. We also review the role of IORT as a radiation boost and specific strategies for successful implementation of IORT in breast cancer.

Identification of potential biomarkers and metabolic pathways based on integration of metabolomic and transcriptomic data in the development of breast cancer

OBJECTIVE

Breast cancer (BC) is the most common type of malignant tumor and the most common cause of cancer-related mortality among women. Metabolic reprogramming is considered a hallmark of cancer, and the study of BC metabolism may be the key to the development of new strategies for diagnosis and treatment. In this study, we aimed to explore the potential metabolites and gene biomarkers for BC through the integration of metabolomics and transcriptomic data, which could further understand BC tumor biology.

METHODS

Transcriptome dataset GSE139038 was downloaded to explore the differentially expressed genes (DEGs) between BC and normal control (NC) samples. Metabolomics dataset MTBLS326 was downloaded and preprocessed to obtain altered metabolites. Then, the principal component analysis (PCA) and linear models were used to reveal DEGs-metabolites relations. Finally, the pathway enrichment analysis of altered metabolites was performed.

RESULTS

A total of 280 DEGs and eight metabolites were explored between BC and NC samples. The liner module analysis investigated 28 DEGs-metabolites interactions including WASP family member 3 (WASF3)-lactate, ras-related protein Rab-7B (RAB7B)-lactate, and methyltransferase-like 7A (METTL7A)-pyruvate. Finally, pathways analysis showed that these metabolites (such as lactate and pyruvate) were mainly enriched in pathways like disorders of the Krebs cycle.

CONCLUSIONS

Combining with the transcriptomic and metabolomics data, we found that lactate, pyruvate, WASF3, RAB7B, and METTL7A might be used as novel biomarkers and potential therapeutic targets for BC. In addition, the disorders of the Krebs cycle pathway might affect the progression of BC.

Five-year results of accelerated partial breast irradiation: A single-institution retrospective review of 289 cases

PURPOSE

The purpose of the study was to describe our institutional experience with accelerated partial breast irradiation (APBI) using multicatheter brachytherapy with high-dose-rate. We report 5-year survival outcomes, cosmesis, and treatment-related toxicity.

METHODS AND MATERIALS

This included a retrospective review of patients who underwent breast-conserving surgery followed by APBI at our institution from 2004 to 2017.

RESULTS

A total of 289 patients were evaluated. Median followup was 72 months. Median age was 70 years. APBI was the only primary treatment in 86.2% of cases with early-stage breast cancer and a second conservative treatment in 13.8%. The implant was performed postoperatively in 213 patients (73.7%) and intraoperatively in 76 (26.3%). The most common radiation schemes were 10 fractions of 3.4 Gy and eight fractions of 4 Gy. Elderly or frail patients (10%) received a single 16 Gy dose. Of the 289 patients, 215 met Groupe Européen de Curiethérapie-European Society for Radiotherapy and Oncology criteria for APBI; in this group, late side effects included Grade 2 (G2) fibrosis (14.8%), skin discoloration at the catheter points (8.8%), and telangiectasia (0.5%). The cosmetic result was considered excellent or good in 88.3% of cases. Five-year local control, disease-free, cancer-specific, and overall survival rates were 98.9%, 96.7%, 99.1%, and 95.6%, respectively.

CONCLUSIONS

Local control and survival outcomes at 5 years of followup in this group of well-selected patients were excellent, with low rates of treatment-related toxicity. These findings confirm the safety and effectiveness of APBI, even in elderly and frail patients. These results provide further support for the clinical use of APBI in suitable patients.

The Acute and Late Toxicities of MRI-Guided External Beam Partial Breast Irradiation Delivered Using a Once-Per-Day Regimen

Background and Purpose

The use of external beam accelerated partial breast irradiation (APBI) using a twice-per-day regimen has raised concerns about increase rates of late toxicities. We compared toxicity outcomes of external beam APBI using a once-per-day regimen and accelerated hypofractionated whole breast irradiation (AWBI) in patients with early-stage breast cancer.

Materials and Methods

This was a single-institution, retrospective cohort study. Patients aged ≥50 years with pTisN0 or pT1N0 breast cancer who underwent breast-conserving surgery and adjuvant radiotherapy were included. APBI was delivered at 38.5 Gy in 10 fractions once daily using magnetic resonance imaging (MRI)-guided radiotherapy only to patients who were strictly “suitable”, according to the ASTRO-APBI guidelines. AWBI was delivered at 40.5–43.2 Gy in 15 or 16 fractions with or without a boost.

Results

Between October 2015 and December 2018, 173 and 300 patients underwent APBI and AWBI, respectively. At a median follow-up of 34.9 months (range 7.1 to 55.4 months), the 3-year recurrence-free survival rates of the APBI and AWBI groups were both 99.2% (p=0.63). Acute toxicities were less frequent in the APBI than AWBI group (grade 1: 95 [54.9%] vs. 233 [77.7%] patients; grade 2: 7 [4.0%] vs. 44 [14.7%] patients; no grade ≥3 toxicities were observed in either group, p<0.001). Late toxicities were less common in the APBI than AWBI group (grade 1: 112 [64.7%] vs. 197 [65.7%] patients; grade 2: 9 [5.2%] vs. 64 [21.3%] patients; grade 3: 0 vs. 5 [1.7%] patients, p<0.001). Multivariate analysis showed that APBI was significantly associated with fewer late toxicities of grade ≥2 compared with AWBI (odds ratio 4.17, p=0.006).

Conclusion

Once-per-day APBI afforded excellent locoregional control and fewer toxicities compared with AWBI. This scheme could be an attractive alternative to AWBI in patients who meet the ASTRO-APBI guidelines.

Outcomes After Accelerated Partial Breast Irradiation in Women With Triple Negative Subtype and Other "High Risk" Variables Categorized as Cautionary in The ASTRO Guidelines

PURPOSE

To report a primary objective clinical outcome of ipsilateral breast recurrence following accelerated partial breast irradiation (APBI) in women with triple negative and other high risk breast cancer (as described in 2017 ASTRO guidelines) (i.e., age 40-49, size 2.1-3.0 cm, estrogen receptor negative and invasive lobular breast cancer). Secondary objectives of axillary and regional failure as well as overall survival are also reported.

METHODS AND MATERIAL

Patients from two clinical trials (NCT01185145, NCT01185132) were treated with 38.5 Gy IMRT or 3D-CRT APBI w/3.85 Gy fraction/BID fractionation for 10 fractions. Triple negative and other high risk patients (n=269) were compared to a total of 478 low risk patients which ASTRO defined as "suitable" for APBI. High risk patients, for the purpose of this study, were defined as those who possess one or more high risk criteria: triple negative (n=30), tumor size >2 cm <3 cm (n=50), HER 2+ (n=54), age range 40-50 years (n=120), ER- (n=43), and ILC histology (n=52).

RESULTS

Median follow up was 4.0 years for all patients. No significant difference was found for this high-risk cohort at 5 years for ipsilateral breast, or regional recurrences. Axillary recurrence was significantly adversely impacted by triple negative and ER- statuses (p=0.01, p=0.04). There were significant correlations between triple negative type and axillary recurrence on multivariate analysis (p=0.03). Overall survival for all patients was unaffected by any of the high-risk categories.

CONCLUSION

The data from this study suggests that women possessing high risk features are at no more meaningful risk for recurrence than other patients considered to be acceptable for APBI treatment. However, the finding of axillary recurrence in patients with triple negative breast cancer does warrant a degree of caution in proceeding with accelerated partial breast irradiation technique in this patient group.

Long-Term Outcomes of Once-Daily Accelerated Partial-Breast Irradiation With Tomotherapy: Results of a Phase 2 Trial

PURPOSE

We report long-term outcomes of phase 2 trial on patients with invasive breast cancer treated with accelerated partial-breast irradiation (APBI) using tomotherapy after breast conservative surgery.

METHODS AND MATERIALS

From December 2010 to December 2018, we treated 338 women with APBI-tomotherapy: 38.5 Gy in 10 once-daily fractions. Patients selected were age ≥50 years old, with ≤3 cm in size unifocal tumor and at least 2 mm of clear margins. Disease outcomes were analyzed by clinicopathologic characteristics, molecular phenotypes, and American Society for Radiation Oncology (ASTRO) 2017 updated consensus groupings.

RESULTS

The median age was 65 years (range, 50-86). The invasive ductal (87.5%) and the luminal A-like molecular phenotype (70%) were the most common tumors. Overall 242 patients (71.6%) were considered "suitable" for enrollment in APBI according to the eligibility criteria of the ASTRO-2017 consensus statement. With a median follow-up of 76 months (range, 17-113), 2 patients (0.6%) had an invasive ipsilateral breast tumor recurrence (IBTR), and 2 patients (0.6%) had an axillary ipsilateral failure. The rate of local control in terms of free of IBTR was 99.4% and locoregional control (no recurrence in ipsilateral breast as well as in regional nodes) was 98.8%. Progression-free survival was 98.4% and 92% at 5 and 10 years, respectively. Acute and late skin toxicity, graded according to the Common Terminology Criteria for Adverse Events, were 7.7% (G1) and 0.6% (G2) and 4.4% (G1) and 1.1% (G2), respectively. There were no grade 3/4 toxicities, however. Very few patients (2%) or physicians (2%) assessed cosmetic outcome as fair or poor at the 2-year follow-up.

CONCLUSIONS

This phase 2 trial on APBI-tomotherapy shows excellent long-term results. Once-daily fractionation schedule was well tolerated with a low rate of adverse events and worse cosmetic outcome. In this series, even among those deemed cautionary or unsuitable for APBI by ASTRO criteria, we demonstrated a low rate of IBTR.

The Case for Brachytherapy: Why It Deserves a Renaissance

The recent global events related to the coronavirus disease of 2019 pandemic have significantly changed the medical landscape and led to a shift in oncologic treatment perspectives. There is a renewed focus on preserving treatment outcomes while maintaining medical accessibility and decreasing medical resource utilization. Brachytherapy, which is a vital part of the treatment course of many cancers (particularly prostate and gynecologic cancers), has the ability to deliver hypofractionated radiation and thus shorten treatment time. Studies in the early 2000s demonstrated a decline in brachytherapy usage despite data showing equivalent or even superior treatment outcomes for brachytherapy in disease sites, such as the prostate and cervix. However, newer data suggest that this trend may be reversing. The renewed call for shorter radiation courses based on data showing equivalent outcomes will likely establish hypofractionated radiation as the standard of care across multiple disease sites. With shifting reimbursement, brachytherapy represents the pinnacle in hypofractionated, conformal radiation therapy, and with extensive long-term data in support of the treatment modality brachytherapy is primed for a renaissance.

Multi-institutional registry study evaluating the feasibility and toxicity of accelerated partial breast irradiation using noninvasive image-guided breast brachytherapy

PURPOSE

The noninvasive image-guided breast brachytherapy (NIBB) technique is a novel noninvasive yet targeted method for accelerated partial breast irradiation. We established a multi-institutional registry to evaluate the toxicity and efficacy of this technique across various practice settings.

METHODS AND MATERIALS

Institutions using the NIBB technique were invited to participate. Data for acute/late toxicity, cosmetic outcome, and tumor recurrence were collected. Toxicity and cosmetic outcome were graded based on the Common Terminology Criteria for Adverse Events version 3.0 and NRG/Radiation Therapy Oncology Group scale, respectively. Treatment variables were analyzed for association with outcomes.

RESULTS

A total of 252 patients from eight institutions were analyzed. The median age was 69 years. The mean tumor size was 1.1 cm (0.1-4.0 cm). Treatment was delivered 10 fractions (34-36 Gy) in 75% and five fractions (28.5 Gy) in 22%. B.i.d. fractionation was used in 9%. Acute radiation dermatitis was Grade 0-1, 2, and 3 in 77%, 19%, and 4%, respectively. One hundred ninety-one patients with a median followup of 18 months (4-72 months) were evaluable for late outcomes. Late toxicity Grades 2 and 3 were observed in 8.8% and 1%, respectively. Cosmetic outcome was excellent, good, and fair/poor in 62%, 36%, and 2%, respectively. B.i.d. fractionation was associated with higher acute and late toxicity. Second-generation applicators were associated with lower late toxicity and better cosmetic outcome. Actuarial freedom from ipsilateral breast tumor recurrence and true recurrence were 98.3% and 98.3% at 2 years and 90.9% and 95.4% at 5 years, respectively.

CONCLUSIONS

Accelerated partial breast irradiation using NIBB was well tolerated with a low rate of acute and late toxicity across various practice settings. Ipsilateral breast tumor recurrence and cosmetic outcomes were favorable. b.i.d. fractionation was associated with higher toxicity. Longer followup is needed to confirm late endpoints.

Implementation of Royal College of Radiologists Consensus Statements and National Institute for Health and Care Excellence Guidance: Breast Radiotherapy Practice in the UK

AIMS

Breast radiotherapy practice, driven by large randomised controls trials, is increasingly being risk adapted to the biology and stage of the cancer. The aim of this audit was to measure current breast radiotherapy practice in the UK against quality standards from the 2016 Royal College of Radiologists (RCR) consensus statements and the 2018 updated National Institute for Health and Care Excellence (NICE) guidelines. These guidelines include new recommendations for partial breast irradiation for women at lower risk of recurrence and internal mammary chain radiotherapy for those at higher risk.

MATERIALS AND METHODS

Radiotherapy departments completed a questionnaire for all patients starting adjuvant radiotherapy for early breast cancer in a 2-week period mid-2019.

RESULTS

Eighty-one per cent of centres returned data on 958 patients, including 18 bilateral cancers. Of 976 breast cancers, 23.9% were treated with mastectomy. The dose fractionation schedule for adjuvant radiotherapy was 40 Gy in 15 fractions in 95.7% of cases. Of the 743 cases treated with breast conservation, 29.9% received an additional tumour bed boost. The boost was given sequentially in 91.9% of cases and with eight different dose fractionation schedules. Of 494 left-sided breast cancer cases, 54% (n = 267) received radiotherapy in deep inspiratory breath hold. All centres except one had a deep inspiratory breath hold technique available. Only 12% of patients who met the RCR criteria for partial breast irradiation received it. Overall, 14.7% and 9.9% of patients meeting the RCR and NICE criteria for internal mammary chain radiotherapy, respectively, received it.

CONCLUSIONS

Despite established consensus statements and NICE guidelines there persists variation in breast radiotherapy practice in the UK. The results of practice-changing trials showing the benefit of cardiac-sparing radiotherapy techniques, partial breast radiotherapy and internal mammary nodal radiotherapy have not been fully implemented. This audit highlights areas for targeted quality improvement and future consensus statements.

Analysis of the electron-stream effect in patients treated with partial breast irradiation using the 1.5 T MR-linear accelerator

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The electron-stream effect is responsible of an out-of-field dose when performing partial breast irradiation at the MR-linac.

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The electron-stream effect is located to the patient́s chin and, for lateral targets, to the arm.

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The electron-stream effect is effectively minimized by a bolus.

•

Novel concepts and clinical trials for breast cancer at the 1.5 T MR-linac can be tested.

Introduction

The hybrid magnetic resonance linear accelerator (MRL) has the potential to test novel concepts in breast cancer patients such as daily MR-guided real-time plan adaptation. Before starting clinical trials, preparatory studies for example of the MR-dependent electron stream effect (ESE) are necessary.

Material and Methods

To prospectively investigate the ESE, data from 11 patients treated with partial breast irradiation (PBI) at the 1.5 T MRL were evaluated. A bolus was placed on the chin and in vivo dosimetry results were compared with the dose simulated by the treatment planning system (TPS). The same measurements were carried out for three patients treated at a conventional linac. Toxicity and cosmesis were evaluated.

Results

Median doses measured and simulated on top/ underneath the bolus were 1.91 / 0.62 Gy and 2.82 / 0.63 Gy, respectively. Median differences between calculations and measurements were 0.8 Gy and 0.1 Gy. At the conventional linac, median measured doses on top/ underneath the bolus were 0.98 and 1.37 Gy. No acute toxicity exceeding grade 2 was recorded. Cosmesis was good or excellent and patient reported outcome measures were mostly scored as none or mild.

Conclusion

The dose due to the ESE is low, correctly predicted by the TPS and effectively minimized by a bolus.

A meta-analysis of the efficacy and safety of accelerated partial breast irradiation versus whole-breast irradiation for early-stage breast cancer

OBJECTIVE

This meta-analysis evaluated the efficacy and safety of accelerated partial breast irradiation versus whole-breast irradiation for early-stage breast cancer after breast-conserving surgery.

MATERIALS AND METHODS

A systematic search of PubMed, Embase, and the Cochrane libraries was performed according to the PRISMA statement the last 10 years to April 7, 2020 to identify the randomized controlled trials of APBI versus WBI for treating patients with early-stage breast cancer. Two independent observers evaluated the identified studies. The obtained data were analyzed using the RevMan 5.3 software.

RESULTS

A total of 10 randomized controlled trials involving 15,500 patients with early-stage breast cancer were selected according to the inclusion and exclusion criteria and included in this meta-analysis. In this meta-analysis, we included ten studies that reported local recurrence and found significant differences in local recurrence rates (HR = 1.46; 95% CI 1.20-1.79, P = 0.0002). Further analysis showed that this difference may be related to the choice of treatment methods. No differences in distant metastasis, breast cancer deaths, contralateral breast cancer, disease-free survival, and overall survival rates were observed between WBI and APBI groups. There was no significant difference in late toxicity, cosmetic outcomes and quality of life between the two groups, the compliance and tolerance of the patients were well. Compared to whole breast irradiation, accelerated partial breast irradiation significantly reduced serious (≥ grade 2) early toxicities, especially regarding acute skin toxicity.

CONCLUSIONS

The analysis showed that patients receiving APBI had a higher local recurrence rate, but no differences in distant metastasis, breast cancer deaths, contralateral breast cancer, disease-free survival, and overall survival rates.

Moderate hypofractionation remains the standard of care for whole-breast radiotherapy in breast cancer: Considerations regarding FAST and FAST-Forward

Moderate hypofractionation is the standard of care for adjuvant whole-breast radiotherapy after breast-conserving surgery for breast cancer. Recently, 10-year results from the FAST and 5‑year results from the FAST-Forward trial evaluating adjuvant whole-breast radiotherapy in 5 fractions over 5 weeks or 1 week have been published. This article summarizes recent data for moderate hypofractionation and results from the FAST and FAST-Forward trial on ultra-hypofractionation. While the FAST trial was not powered for comparison of local recurrence rates, FAST-Forward demonstrated non-inferiority for two ultra-hypofractionated regimens in terms of local control. In both trials, the higher-dose experimental arms resulted in elevated rates of late toxicity. For the lower dose experimental arms of 28.5 Gy over 5 weeks and 26 Gy over 1 week, moderate or marked late effects were similar in the majority of documented items compared to the respective standard arms, but significantly worse in some subdomains. The difference between the standard arm and the 26 Gy of the FAST-Forward trial concerning moderate or marked late effects increased with longer follow-up in disadvantage of the experimental arm for most items. For now, moderate hypofractionation with 40–42.5 Gy over 15–16 fractions remains the standard of care for the majority of patients with breast cancer who undergo whole-breast radiotherapy without regional nodal irradiation after breast-conserving surgery.

Breast conservation among older patients with early-stage breast cancer: Locoregional recurrence following adjuvant radiation or hormonal therapy

BACKGROUND

For patients with breast cancer undergoing breast-conserving surgery (BCS), adjuvant radiation (RT) and hormonal therapy (HT) reduce the risk of locoregional recurrence (LRR). Although several studies have evaluated adjuvant HT ± RT, the outcomes of HT versus RT monotherapy remain less clear. In this study, the risk of LRR is characterized among older patients with early-stage breast cancer following adjuvant RT alone, HT alone, neither, or both.

METHODS

This study included female patients from the Memorial Sloan Kettering Cancer Center (New York, New York) who were aged ≥65 years with estrogen receptor-positive (ER+)/human epidermal growth factor receptor 2-negative (HER2-) T1N0 breast cancer treated with BCS. The primary endpoint was time to LRR evaluated by Cox regression analysis.

RESULTS

There were 888 women evaluated with a median age of 71 years (range, 65-100 years) and median follow-up of 4.9 years (range, 0.0-9.5 years). There were 27 LRR events (3.0%). Five-year LRR was 11% for those receiving no adjuvant treatment, 3% for HT alone, 4% for RT alone, and 1% for HT and RT. LRR rates were significantly different between the groups (P < .001). Compared with neither HT nor RT, HT or RT monotherapy each yielded similar LRR reductions: HT alone (HR, 0.27; 95% CI, 0.10-0.68; P = .006) and RT alone (HR, 0.32; 95% CI, 0.11-0.92; P = .034). Distant recurrence and breast cancer-specific survival rates did not significantly differ between groups.

CONCLUSIONS

LRR risk following BCS is low among women aged ≥65 years with T1N0, ER+/HER2- breast cancer. Adjuvant RT and HT monotherapy each similarly reduce this risk; the combination yields a marginal improvement. Further study is needed to elucidate whether appropriate patients may feasibly receive adjuvant RT monotherapy versus the current standards of HT monotherapy or combined RT/HT.

Can we rely on surgical clips placed during oncoplastic breast surgery to accurately delineate the tumor bed for targeted breast radiotherapy?

PURPOSE

Oncoplastic breast surgery (OBS) is gaining popularity among surgeons for breast-conserving surgery treatments. OBS relies on complex relocation and deformation of breast tissue involving the tumor bed (TB). In this study, we investigate the validity of using surgical clips with OBS for accurate TB delineation in adjuvant, targeted breast radiotherapy.

METHODS

Different OBS techniques were simulated on realistic breast phantoms. Surgical clips were used to demarcate the TB. Following tumor resection and closure, the true TB (TB_True) was extracted. Each phantom was CT imaged at several phases of surgery in order to record pre- and post-OBS closure surgical clip displacements. Two senior radiation oncologists (ROs) were asked to delineate TBs on CTs by relying on surgical clips placed as per standard protocol, and by referring to operative notes. Their original contours, as well as those expanded using 5-15 mm margins, were compared with the accurate TB_True using the dice similarity coefficient (DSC), Hausdorff Distance (HD), and over- and under-contoured volumes. Inter- and intra-RO contour agreements were also evaluated.

RESULTS

Post-OBS surgical clips were significantly displaced outside the original breast quadrant. Inter- and Intra-RO TB contours were consistent, yet systematically differed from TB_True (DSC values range = 0.38 to 0.69, and maximum HD range = 17.8 mm to 38.0 mm). Using expansion margins did not improve contour congruence and caused significant over-contoured volumes.

CONCLUSION

Following OBS, surgical clips alone are not reliable radiographic surrogates of TB locations and accurate TB delineation is challenging. For complex OBS cases, indication of any type of partial breast irradiation is very questionable.

Improved Ipsilateral Breast and Chest Wall Sparing With MR-Guided 3-fraction Accelerated Partial Breast Irradiation: A Dosimetric Study Comparing MR-Linac and CT-Linac Plans

Purpose

External beam accelerated partial breast irradiation (APBI) is subject to treatment uncertainties that must be accounted for through planning target volume (PTV) margin. We hypothesize that magnetic resonance–guided radiation therapy with reduced PTV margins enabled by real-time cine magnetic resonance image (MRI) target monitoring results in better normal tissue sparing compared with computed tomography (CT)-guided radiation therapy with commonly used clinical PTV margins. In this study, we compare the plan quality of ViewRay MRIdian Linac forward planned intensity modulated radiation therapy and TrueBeam volumetric modulated arc therapy for a novel 3-fraction APBI schedule.

Methods and Materials

Targets and organs at risk (OARs) were segmented for 10 patients with breast cancer according to NSABP B39/RTOG 0413 protocol. A 3 mm margin was used to generate MR PTV_3mm and CT PTV_3mm plans, and a 10 mm margin was used for CT PTV_10mm. An APBI schedule delivering 24.6 Gy to the clinical target volume and 23.4 Gy to the PTV in 3 fractions was used. OAR dose constraints were scaled down from existing 5-fraction APBI protocols. Target and OAR dose-volume metrics for the following data sets were analyzed using Wilcoxon matched-pairs signed-rank test: (1) MR PTV_3mm versus CT PTV_3mm plans and (2) MR PTV_3mm versus CT PTV_10mm.

Results

Average PTVs were 84.3 ± 51.9 cm³ and 82.6 ± 55 cm³ (P = .5) for MR PTV_3mm and CT PTV_3mm plans, respectively. PTV V23.4Gy, dose homogeneity index, conformity index (CI), and R50 were similar. There was no meaningful difference in OAR metrics, despite MR PTV_3mm being larger than the CT PTV_3mm in 70% of the patients. Average PTVs for MR PTV_3mm and CT PTV_10mm plans were 84.3 ± 51.9 cm³ and 131.7 ± 74.4 cm³, respectively (P = .002). PTV V23.4Gy was 99% ± 0.9% versus 97.6% ± 1.4% (P = .03) for MR PTV_3mm and CT PTV_10mm, respectively. Dose homogeneity index, CI, and R50 were similar. MR PTV_3mm plans had better ipsilateral breast (V12.3Gy, 34.8% ± 12.7% vs 44.4% ± 10.9%, P = .002) and chest wall sparing (V24Gy, 8.5 ± 5.5 cm³ vs 21.8 ± 14.9 cm³, P = .004).

Conclusions

MR- and CT-based planning systems produced comparable plans when a 3 mm PTV margin was used for both plans. As expected, MR PTV_3mm plans produced better ipsilateral breast and chest wall sparing compared with CT PTV_10mm. The clinical relevance of these differences in dosimetric parameters is not known.

Effectiveness of intraoperative radiotherapy vs hypofractionated postmastectomy radiotherapy for early stage breast cancer: A protocol for systematic review and meta-analysis

BACKGROUND

Radiotherapy is one of the essential components of breast cancer treatment. It destroys the remaining cells in the chest area after breast cancer surgery and is useful for reducing the necessity of mastectomies. As a single dose of radiation at the time of breast conserving surgery, intraoperative radiotherapy delivers radiotherapy directly and accurately to the tumor itself or the tumor bed whilst delivering minimal dose to the surrounding normal tissues. Hypofractionated postmastectomy radiotherapy with shorter and more convenient hypofractionated dose schedules might help to treat more patients and reduce cost. We will conduct a comprehensive systematic review and meta-analysis to compare the effectiveness of these 2 therapies in the management of early stage breast cancer.

METHODS

Four English databases (PubMed, Embase, Cochrane Library, and Web of Science) and 3 Chinese databases (China National Knowledge Infrastructure, China Science and Technology Journal Database, and Chinese Biomedical Literature Database) will be searched from inception of databases to December 2020 without language limitation. Two reviewers will independently conduct selection of studies, data extraction and management, and assessment of risk of bias. Any disagreement will be resolved by the third reviewer. Review Manager 5.3 (The Cochrane Collaboration, Software Update, Oxford, UK) will be used for data synthesis. Cochrane risk of bias assessment tool will be used to assess the risk of bias.

RESULTS

This study will provide a systematic synthesis of current published data to compare the effectiveness of intraoperative radiotherapy vs hypofractionated postmastectomy radiotherapy for early stage breast cancer.

CONCLUSIONS

This systematic review and meta-analysis will provide clinical evidence for the effectiveness of intraoperative radiotherapy vs hypofractionated postmastectomy radiotherapy for early stage breast cancer, and inform our understanding of the value of intraoperative radiotherapy and hypofractionated postmastectomy radiotherapy for early stage breast cancer.

STUDY REGISTRATION NUMBER

INPLASY2020110115.

Hypofractionated radiotherapy in the real-world setting: An international ESTRO-GIRO survey

BACKGROUND AND PURPOSE

Multiple large trials have established the non-inferiority of hypofractionated radiotherapy compared to conventional fractionation. This study will determine real-world hypofractionation adoption across different geographic regions for breast, prostate, cervical cancer, and bone metastases, and identify barriers and facilitators to its use.

MATERIALS AND METHODS

An anonymous, electronic survey was distributed from January 2018 through January 2019 to radiation oncologists through the ESTRO-GIRO initiative. Predictors of hypofractionation were identified in univariable and multivariable regression analyses.

RESULTS

2316 radiation oncologists responded. Hypofractionation was preferred in node-negative breast cancer following lumpectomy (82·2% vs. 46·7% for node-positive; p < 0.001), and in low- and intermediate-risk prostate cancer (57·5% and 54·5%, respectively, versus 41·2% for high-risk (p < 0.001)). Hypofractionation was used in 32·3% of cervix cases in Africa, but <10% in other regions (p < 0.001). For palliative indications, hypofractionation was preferred by the majority of respondents. Lack of long-term data and concerns about local control and toxicity were the most commonly cited barriers. In adjusted analyses, hypofractionation was least common for curative indications amongst low- and lower-middle-income countries, Asia-Pacific, female respondents, small catchment areas, and in centres without access to intensity modulated radiotherapy.

CONCLUSION

Significant variation was observed in hypofractionation across curative indications and between regions, with greater concordance in palliation. Using inadequate fractionation schedules may impede the delivery of affordable and accessible radiotherapy. Greater regionally-targeted and disease-specific education on evidence-based fractionation schedules is needed to improve utilization, along with best-case examples addressing practice barriers and supporting policy reform.

Local Treatment of Triple-Negative Breast Cancer

ABSTRACT

Triple-negative breast cancer, compared with other molecular subtypes, poses particular challenges for optimizing the timing and the extent of locoregional treatments. In the past, the combination of increased rates of both locoregional and distant recurrences led to a preference of radical surgery and extensive radiation therapy; however, since the introduction of more effective chemotherapy, a sharp de-escalation in the extent of locoregional treatments followed. Current evidence confirms that less aggressive surgery in combination with tailored radiation therapy offers improved oncological outcomes combined with better quality of life. However, further research is required to optimize locoregional treatments, considering the significant heterogeneity in biological behavior and tumor response to systemic treatments.

The therapeutic significance of the novel photodynamic material TPE-IQ-2O in tumors

Combination therapies based on photodynamic therapy (PDT) have received much attention in various cancers due to their strong therapeutic effects. Here, we aimed to explore the safety and effectiveness of a new mitochondria-targeting photodynamic material, TPE-IQ-2O, in combination therapies (combined with surgery or immunotherapy). The safety and effectiveness of TPE-IQ-2O PDT were verified with cytotoxicity evaluation in vitro and a zebrafish xenograft model in vivo, respectively. The effectiveness of TPE-IQ-2O PDT combined with surgery or immune checkpoint inhibitors (ICIs) was verified in tumor-bearing mice. Small animal in vivo imaging, immunohistochemistry, and flow cytometry were used to determine the underlying mechanism. TPE-IQ-2O PDT can not only reduce tumor recurrence in surgical treatment but also effectively improve the response to ICIs in immunotherapy without obvious toxicity. It was also found to ameliorate the immunosuppressive tumor microenvironment and promote the antitumor immunity induced by ICIs by increasing CD8⁺ tumor-infiltrating lymphocyte accumulation. Thus, TPE-IQ-2O PDT is a safe and effective antitumor therapy that can be combined with surgery or immunotherapy.

Minimally invasive tumor bed implant (MITBI) and peri-operative high-dose-rate brachytherapy (PHDRBT) for accelerated minimal breast irradiation (AMBI) or anticipated boost (A-PHDRBT-boost) in breast-conserving surgery for ductal carcinoma in situ

Purpose

To evaluate our institutional experience of minimally invasive tumor bed implantation (MITBI) during breast-conserving surgery (BCS) for ductal carcinoma in situ (DCIS) to deliver peri-operative high-dose-rate brachytherapy (PHDRBT) as accelerated minimal breast irradiation (AMBI) or anticipated boost (A-PHDRBT-boost).

Material and methods

Patients older than 40, with clinical and radiological unifocal DCIS < 3 cm were considered potential candidates for accelerated partial breast irradiation (APBI) and were implanted during BCS using MITBI-technique. Patients who in final pathology reports showed free margins and no other microscopic tumor foci, received AMBI with PHDRBT (3.4 Gy BID in 5 days). Patients with adverse features received A-PHDRBT-boost with post-operative external beam radiotherapy (EBRT).

Results

Forty-one patients were implanted, and 36 were treated and analyzed. According to final pathology, 24 (67%) patients were suitable for AMBI and 12 (33%) were qualified for A-PHDRBT-boost. Reoperation rate for those with clear margins was 16.6% (6/36); this rate increased to 33% (4/12) for G3 histology, and 66% (4/6) were rescued using AMBI. Early complications were documented in 5 patients (14%). With a median follow-up of 97 (range, 42-138) months, 5-year rates of local, elsewhere, locoregional, and distant control were all 97.2%. 5-year ipsilateral breast tumor recurrence rates (IBTR) were 5.6% (2/36), 8.3% (2/24) for AMBI, and 0% (0/12) for A-PHDRBT-boost patients. Both instances of IBTR were confirmed G3 tumors in pre-operative biopsies; no IBTR was documented in G1-2 tumors. Cosmetic outcomes were excellent/good in 96% of AMBI vs. 67% in A-PHDRBT-boost (p = 0.034).

Conclusions

The MITBI-PHDRBT program allows selection of patients with excellent prognoses (G1-2 DCIS with negative margins and no multifocality), for whom AMBI could be a good alternative with low recurrence rate, decrease of unnecessary radiation, treatment logistics improvement, and over-treatment reduction. Patients whose pre-operative biopsy showed G3 tumor, presents with inferior local control and more risk of reoperation due to positive margins.

Management of ductal carcinoma in situ with accelerated partial breast irradiation brachytherapy: Implications for guideline expansion

PURPOSE

Accelerated partial breast irradiation (APBI) for patients with ductal carcinoma in situ (DCIS) is controversial, and the suitability criteria from the American Brachytherapy Society (ABS), American Society of Therapeutic Radiology and Oncology (ASTRO), and the European Society for Radiotherapy and Oncology (GEC-ESTRO) have important differences.

METHODS AND MATERIALS

This is a single-institution retrospective review of 169 consecutive patients with DCIS who underwent lumpectomy followed by APBI intracavitary brachytherapy from 2003 to 2018. Outcomes, including overall survival, recurrence-free survival (RFS), ipsilateral breast tumor recurrence, and distant metastasis, were estimated with the Kaplan-Meier method.

RESULTS

The median followup time was 62.5 months. Median age was 66 years (47-89 years). The majority of patients had estrogen receptor-positive disease (89%). Fifty patients (30%) had Grade 3 disease. Of the 142 patients with adequate pathology interpretation, 91 and 108 cases had margins ≥ 3 mm and ≥2 mm, respectively. Most patients (72%) were prescribed and started endocrine therapy. Of the patients evaluable for ABS criteria (N = 130), 97 met the suitability criteria. Of the patients evaluable for ASTRO criteria (N = 129), 42 were deemed cautionary and 33 were deemed unsuitable. Of the patients evaluable for GEC-ESTRO criteria (N = 143), 141 cases were at intermediate risk and two were at high risk. Five-year ipsilateral breast tumor recurrence, RFS, and overall survival were 0.6%, 97.7%, and 97.2%, respectively. The ABS, ASTRO, and GEC-ESTRO criteria failed to significantly predict for RFS.

CONCLUSIONS

These results, although limited by short-term followup, indicate that expansion of the eligibility criteria of APBI for patients with DCIS should be considered.

Accelerated Partial-Breast Irradiation Compared With Whole-Breast Irradiation for Early Breast Cancer: Long-Term Results of the Randomized Phase III APBI-IMRT-Florence Trial

PURPOSE

To report the long-term results of external-beam accelerated partial-breast irradiation (APBI) intensity-modulated radiation therapy (IMRT) Florence phase III trial comparing whole-breast irradiation (WBI) to APBI in early-stage breast cancer.

PATIENTS AND METHODS

The primary end point was to determine the 5-year difference in ipsilateral breast tumor recurrence (IBTR) between 30 Gy in 5 once-daily fractions (APBI arm) and 50 Gy in 25 fractions with a tumor bed boost (WBI arm) after breast-conserving surgery.

RESULTS

Five hundred twenty patients, more than 90% of whom had characteristics associated with low recurrence risk, were randomly assigned (WBI, n = 260; APBI, n = 260) between 2005 and 2013. Median follow-up was 10.7 years. The 10-year cumulative incidence of IBTR was 2.5% (n = 6) in the WBI and 3.7% (n = 9) in the APBI arm (hazard ratio [HR], 1.56; 95% CI, 0.55 to 4.37; P = .40). Overall survival at 10 years was 91.9% in both arms (HR, 0.95; 95% CI, 0.50 to 1.79; P = .86). Breast cancer–specific survival at 10 years was 96.7% in the WBI and 97.8% in the APBI arm (HR, 0.65; 95% CI, 0.21 to 1.99; P = .45). The APBI arm showed significantly less acute toxicity ( P = .0001) and late toxicity ( P = .0001) and improved cosmetic outcome as evaluated by both physician ( P = .0001) and patient ( P = .0001).

CONCLUSION

The 10-year cumulative IBTR incidence in early breast cancer treated with external APBI using IMRT technique in 5 once-daily fractions is low and not different from that after WBI. Acute and late treatment-related toxicity and cosmesis outcomes were significantly in favor of APBI.

Toward Improving Patients' Experiences of Acute Toxicity From Breast Radiotherapy: Insights From the Analysis of Patient-Reported Outcomes in a Large Multicenter Cohort

PURPOSE

Understanding acute toxicities after whole-breast radiotherapy is important to inform patients, guide treatment decisions, and target supportive care. We evaluated patient-reported outcomes prospectively collected from a cohort of patients with breast cancer.

METHODS

We describe the maximal toxicity reported by 8,711 patients treated between 2012 and 2019 at 27 practices. Multivariable models identified characteristics associated with (1) breast pain, (2) bother from itching, stinging/burning, swelling, or hurting of the treated breast, and (3) fatigue within 7 days of completing whole-breast radiotherapy.

RESULTS

Moderate or severe breast pain was reported by 3,233 (37.1%): 1,282 (28.9%) of those receiving hypofractionation and 1,951 (45.7%) of those receiving conventional fractionation. Frequent bother from at least one breast symptom was reported by 4,424 (50.8%): 1,833 (41.3%) after hypofractionation and 2,591 (60.7%) after conventional fractionation. Severe fatigue was reported by 2,008 (23.1%): 843 (19.0%) after hypofractionation and 1,165 (27.3%) after conventional fractionation. Among patients receiving hypofractionated radiotherapy, younger age (P < .001), higher body mass index (BMI; P < .001), Black (P < .001) or other race (P = .002), smoking status (P < .001), larger breast volume (P = .002), lack of chemotherapy receipt (P = .004), receipt of boost treatment (P < .001), and treatment at a nonteaching center predicted breast pain. Among patients receiving conventionally fractionated radiotherapy, younger age (P < .001), higher BMI (P = .003), Black (P < .001) or other race (P = .002), diabetes (P = .001), smoking status (P < .001), and larger breast volume (P < .001) predicted breast pain.

CONCLUSION

In this large observational data set, substantial differences existed according to radiotherapy dose fractionation. Race-related differences in pain existed despite controlling for multiple other factors; additional research is needed to understand what drives these differences to target potentially modifiable factors. Intensifying supportive care may be appropriate for subgroups identified as being vulnerable to greater toxicity.

Very accelerated partial breast irradiation Phase I-II multicenter trial (VAPBI): Feasibility and early results

PURPOSE

This is a multicenter Phase I-II trial endorsed by the GEC-ESTRO Breast Working Group, to analyze if very accelerated partial breast irradiation (VAPBI) with multicatheter interstitial brachytherapy is feasible and safe compared with the standard APBI treatment in 4-5 days for early stage breast carcinomas.

METHODS AND MATERIALS

We have included 81 patients with pT1-2 pN0 invasive carcinomas after breast-conserving surgery. Between August 2017 and July 2019, 33 women received high-dose-rate brachytherapy, four fractions of 6.25 Gy in 2-3 days, and 48 patients received three fractions of 7.45 Gy in 2 days. Thirty-six patients were implanted perioperatively and 45 postoperatively. Mean age was 68 (51-90). Free surgical margins were of 2 mm or greater.

RESULTS

Acute effects were 11% dermatitis, 18.5% hematoma, 3.7% infection, and 14.8% pain. At a median followup of 20 months (range 8-35), no relapse has occurred. Pigmentation changes in the entrance and exit of tubes were visible in 16%, but 1 year later, few cases remained. Patients developed G1-2 induration or fibrosis in 18.5% and 2.5%, respectively. No patient developed telangiectasia. The cosmetic outcome was good/excellent in 97.5% and fair in 2.5%.

CONCLUSIONS

VAPBI with multicatheter interstitial brachytherapy using four fractions of 6.25 Gy or three fractions of 7.45 Gy in two or 3 days is feasible. No excess has been observed in acute effects. At a mean followup of 20 months, late side effects seem to be similar to standard fractionation. VAPBI in two to 3 days is beneficial for the patients and reduces the workload of the brachytherapy units.

Results of accelerated partial breast irradiation in patients not suitable for external beam irradiation stratified by GEC-ESTRO, ASTRO, and ABS guidelines

PURPOSE

This study aims to review the outcome of an institution in multicatheter/interstitial accelerated partial breast irradiation (MC-APBI) for treatment of patients with breast cancer, either with strong criteria for APBI or unable to be treated with whole-breast irradiation. The outcomes were also stratified by the American Society for Radiation Oncology, American Brachytherapy Society, and Groupe Européen de Curiethérapie-European Society for Therapeutic Radiology and Oncology patient selection criteria.

METHODS

The study includes 118 patients and 120 MC-APBI treatments, treated in a single tertiary center, between November 2003 and August 2016. The analysis is focused on the clinical baseline characteristics, local control, relapse-free survival, disease-specific survival (DSS), and overall survival.

RESULTS

In accordance to the American Society for Radiation Oncology, American Brachytherapy Society, and Groupe Européen de Curiethérapie-European Society for Therapeutic Radiology and Oncology, 17.1% were "unsuitable," 19.2% were "unacceptable," and 19.5% were "high risk," respectively. The main reasons why high-risk patients were submitted to MC-APBI were as follows: cardiopathy (n = 7), social difficulties (n = 4), and mobility limitations (n = 4). At the median followup period of 86.5 months, ipsilateral breast tumor recurrence was observed in one (0.8%) patient. The 3-year and 5-year relapse-free survival were 100% and 99.1%, respectively. DSS was 100%.

CONCLUSIONS

This study demonstrated excellent control rates, DFS, and DSS of MC-APBI, rendering APBI as an excellent treatment for patients with breast cancer, even those who are not necessarily eligible for this treatment approach. The selection criteria for ABPI diverge according to different guidelines and are based on studies with discrepancies, making extremely possible that these recommendations could be changed.

A clinical study of curative partial breast irradiation for stage I breast cancer using carbon ion radiotherapy

Background and purpose

Our institute initiated carbon ion radiotherapy research for patients with stage I breast cancer in April 2013. The purpose of this article is to evaluate the treatment outcome of cases treated outside clinical trial up to May 2020.

Materials and methods

Eligibility criteria of the patients were having untreated stage I breast cancer and being unsuitable for operation for physical or mental reasons. The irradiated volume was defined as the gross tumor including intraductal components. The dose escalation study was initially conducted four times a week for a total of 52.8 Gy [relative biological efficacy (RBE)]. After confirming that adverse effects were within acceptable range, the total dose was increased to 60.0 Gy (RBE).

Results

Between April 2013 and November 2015, 14 cases were treated. The median follow up period was 61 months. No adverse toxicities were observed except for grade 1 acute skin reaction in 10 cases. The time required from carbonion radiotherapy to tumor disappearance was 3 months in 1 case, 6 months in 3 cases, 12 months in 4 cases, and 24 months in 5 cases. The third case developed local recurrence 6 months after radiotherapy. Twelve patients with luminal subtype received 5-year endocrine therapy. Thirteen of 14 tumors have been maintaining complete response with excellent cosmetic results.

Conclusions

The time from carbon ion radiotherapy to tumor disappearance was longer than expected, but complete tumor disappearance was observed except for one high-grade case. With careful patient selection, carbonion radiotherapy in patients with stage I breast cancer is deemed effective and safe, and further research is recommended.

Breast-Conserving Surgery Followed by Partial or Whole Breast Irradiation: Twenty-Year Results of a Phase 3 Clinical Study

PURPOSE

To report the 20-year results of a phase 3 clinical trial comparing the survival and cosmetic results of breast-conserving surgery followed by partial breast irradiation (PBI) or whole breast irradiation (WBI).

METHODS AND MATERIALS

Between 1998 and 2004, 258 selected patients with low-risk invasive breast carcinoma (pT1 pN0-1mi, grade 1-2, nonlobular breast cancer) resected with negative margins were randomized after breast-conserving surgery to receive PBI (n = 128) or 50 Gy WBI (n = 130). Partial breast irradiation was given either by multicatheter high-dose-rate (HDR) brachytherapy (BT; n = 88) with 7 × 5.2 Gy twice daily or 50 Gy external beam irradiation with electron beams (n = 40).

RESULTS

Median follow-up time was 17 years. The 20-year actuarial rates of ipsilateral breast tumor recurrences were 9.6% versus 7.9% (P = .59) in the PBI and WBI arms, respectively. There was no significant difference in the 20-year probability of disease-free (79.7% vs 78.3%), cancer-specific (92.6% vs 88.1%), and overall survival (59.5% vs 59.7%). Significantly more patients had excellent or good cosmetic result in the PBI and WBI groups (79.2% vs 59.5%; P = .0007).

CONCLUSIONS

The 20-year updated results of our phase 3 clinical trial add further scientific evidence that PBI either with multicatheter HDR BT or electron beams for low-risk invasive breast carcinomas yield long-term local tumor control and survival comparable to those achieved with standard WBI. Interstitial HDR BT improved cosmetic results compared with WBI.

Accelerated partial breast irradiation with 3-dimensional conformal and image-guided intensity-modulated radiotherapy following breast conserving surgery - 7-Year results of a phase II trial

Purpose

To present the 7-year results of accelerated partial breast irradiation (APBI) using three-dimensional conformal (3D-CRT) and image-guided intensity-modulated radiotherapy (IG-IMRT) following breast-conserving surgery (BCS).

Patients and methods

Between 2006 and 2014, 104 patients were treated with APBI given by means of 3D-CRT using 3–5 non-coplanar, isocentric wedged fields, or IG-IMRT using kV-CBCT. The total dose of APBI was 36.9 Gy (9 × 4.1 Gy) using twice-a-day fractionation. Survival results, side effects and cosmetic results were assessed.

Results

At a median follow-up of 90 months three (2.9%) local recurrences, one (0.9%) regional recurrence and two (1.9%) distant metastases were observed. The 7-year local (LRFS), recurrence free survival was 98.9%. The 7-year disease-free (DFS), metastases free (MFS) and overall survival (OS) was 94.8%, 97.9% and 94.8%, respectively. Late side effects included G1 skin toxicity in 15 (14.4%), G1, G2, and G3 fibrosis in 26 (25%), 3 (2.9%) and 1 (0.9%) patients respectively. Asymptomatic (G1) fat necrosis occurred in 10 (9.6%) patients. No ≥ G2 or higher late side effects occurred with IMRT. The rate of excellent/good and fair/poor cosmetic results was 93.2% and 6.8%, respectively.

Conclusion

7-year results of APBI with 3D-CRT and IG-IMRT are encouraging. Toxicity profile and local tumor control are comparable to other series using multicatheter interstitial brachytherapy. Therefore, these external beam APBI techniques are valid alternatives to whole breast irradiation and brachytherapy based APBI.

•

Phase II APBI trial using 3D-CRT or IG-IMRT.

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Twice-a-day fractionation, with a total dose of 36.9 Gy (9 × 4.1Gy).

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No Grade 2 or worst late side effects with IG-IMRT at median follow up of 90 months.

•

These APBI techniques are valid alternatives to WBI or brachytherapy based APBI.

Consensus on Contouring Primary Breast Tumors on MRI in the Setting of Neoadjuvant Partial Breast Irradiation in Trials

PURPOSE

Our purpose was to present and evaluate expert consensus on contouring primary breast tumors on magnetic resonance imaging (MRI) in the setting of neoadjuvant partial breast irradiation in trials.

METHODS AND MATERIALS

Expert consensus on contouring guidelines for target definition of primary breast tumors on contrast-enhanced MRI in trials was developed by an international team of experienced breast radiation oncologists and a dedicated breast radiologist during 3 meetings. At the first meeting, draft guidelines were developed through discussing and contouring 2 cases. At the second meeting 6 breast radiation oncologists delineated gross tumor volume (GTV) in 10 patients with early-stage breast cancer (cT1N0) according to draft guidelines. GTV was expanded isotropically (20 mm) to generate clinical target volume (CTV), excluding skin and chest wall. Delineations were reviewed for disagreement and guidelines were clarified accordingly. At the third meeting 5 radiation oncologists redelineated 6 cases using consensus-based guidelines. Interobserver variation of GTV and CTV was assessed using generalized conformity index (CI). CI was calculated as the sum of volumes each pair of observers agreed upon, divided by the sum of encompassing volumes for each pair of observers.

RESULTS

For the 2 delineation sessions combined, mean GTV ranged between 0.19 and 2.44 cm3, CI for GTV ranged between 0.28 and 0.77, and CI for CTV between 0.77 and 0.94. The largest interobserver variation in GTV delineations was observed in cases with extended tumor spiculae, blood vessels near or markers within the tumor, or with increased enhancement of glandular breast tissue. Consensus-based guidelines stated to delineate all visible tumors on contrast enhanced-MRI scan 1 to 2 minutes after contrast injection and if a marker was inserted in the tumor to include this.

CONCLUSIONS

Expert-based consensus on contouring primary breast tumors on MRI in trials has been reached. This resulted in low interobserver variation for CTV in the context of a uniform 20 mm GTV to CTV expansion margin.

Who are the optimal candidates for partial breast irradiation?

At the 2017 St. Gallen International Expert Consensus Conference on the Primary Therapy for Early Breast Cancer, the consensus panel recognized "partial breast irradiation as an option for women meeting the low-risk criteria put forward by the American Society for Radiation Oncology/European Society for Radiotherapy and Oncology (ASTRO/ESTRO) guideline," although acknowledging that there was less evidence for this approach. Partial breast irradiation is defined as irradiation localized to the surgical resection cavity only as opposed to the entire breast. Accelerated partial breast irradiation (APBI) involves intensive treatment in a short time period. The methods vary, and three available APBI options are brachytherapy, external beam and intra-operative irradiation. The long-term follow-up results from two large-scale, well-designed phase III randomized clinical trials have been released. However, further discussion of the optimal treatment candidates and delivery method is needed before the clinical application of APBI as a mainstream breast conservation treatment.

Accelerated Partial Breast Irradiation (APBI): Where Are We Now?

Purpose of Review

Accelerated partial breast irradiation (APBI) is an alternative approach to breast conserving therapy (BCT) where radiation (RT) is delivered over a shorter period of time compared with whole breast irradiation (WBI), resulting in improved patient convenience and cost savings. APBI can be delivered using brachytherapy, intraoperative RT, or conformal external beam radiation therapy (EBRT) techniques. In this review, the authors appraise the latest modern randomized controlled trials (RCTs) of APBI and discuss the application of the data to clinical practice.

Recent Findings

The OCOG-RAPID and NSABP B-39/RTOG 0413 trials recently reported long-term outcomes of APBI. The OCOG-RAPID trial delivered 38.5 Gy/10 fractions twice daily (at least 6 h apart using EBRT) or WBI and demonstrated non-inferiority of APBI compared with WBI (8-year cumulative rate of ipsilateral breast tumor recurrence (IBTR) was 3% after APBI or 2.8% after WBI, HR 1.27, 90%CI: 0.84–1.91). While acute toxicity was reduced, late toxicity and breast cosmesis were worse with APBI. The NSABP B-39 trial included higher risk patients and was unable to demonstrate equivalence between APBI (38.5 Gy/10 fractions delivered twice daily using EBRT or brachytherapy techniques) and WBI. However, 10-year IBTR rates were low: 4.6% vs. 3.9%, respectively, HR 1.22, 90%CI: 0.94–1.58. The University of Florence demonstrated low rates of local recurrence at 10 years and overall excellent breast cosmetic outcomes when APBI was delivered using EBRT to a dose of 30 Gy/5 fractions delivered on non-consecutive days.

Summary

Recent RCTs of APBI have shed light on important factors for the integration of APBI into clinical practice, including patient selection and treatment delivery. APBI should be limited to patients with low-risk ductal carcinoma in situ or early stage (T1) invasive ductal cancer with clear margins of excision, estrogen receptor positivity, and node negative disease. Ongoing research should focus on the optimal dose/fractionation for delivery of EBRT-based APBI.

Modeling and comparing data mining algorithms for prediction of recurrence of breast cancer

Breast cancer is the most common invasive cancer and the second leading cause of cancer death in women. and regrettably, this rate is increasing every year. One of the aspects of all cancers, including breast cancer, is the recurrence of the disease, which causes painful consequences to the patients. Moreover, the practical application of data mining in the field of breast cancer can help to provide some necessary information and knowledge required by physicians for accurate prediction of breast cancer recurrence and better decision-making. The main objective of this study is to compare different data mining algorithms to select the most accurate model for predicting breast cancer recurrence. This study is cross-sectional and data gathering of this research performed from June 2018 to June 2019 from the official statistics of Ministry of Health and Medical Education and the Iran Cancer Research Center for patients with breast cancer who had been followed for a minimum of 5 years from February 2014 to April 2019, including 5471 independent records. After initial pre-processing in dataset and variables, seven new and conventional data mining algorithms have been applied that each one represents one kind of data mining approach. Results show that the C5.0 algorithm possibly could be a helpful tool for the prediction of breast cancer recurrence at the stage of distant recurrence and nonrecurrence, especially in the first to third years. also, LN involvement rate, Her2 value, Tumor size, free or closed tumor margin were found to be the most important features in our dataset to predict breast cancer recurrence.

Long-Term Results of Partial Breast Irradiation After Breast-Conserving Surgery for Early Stage Breast Cancer: A Prospective Phase II Trial in China

Background

Partial breast radiotherapy (PBI) has emerged as an option after breast-conserving surgery for early stage breast cancer patients.

Methods

A total of 55 patients with early stage breast cancer between 2009 and 2013 were enrolled in this single-institutional phase II prospective clinical trial. All patients received adjuvant PBI-IMRT after lumpectomy, with the prescription of 48 Gy in 12 fractions at 4 Gy per fraction, 5 days a week. The primary endpoint was ipsilateral breast tumor recurrence (IBTR), the other endpoints were a regional nodal failure (RNF), distant metastasis (DM) rate, disease-free survival (DFS), and overall survival (OS). These endpoints were used to evaluate clinical outcomes. The cosmetic effects and the late toxicity were assessed according to Harvard standard scale and CTCAE 3.0, respectively.

Results

In our cohorts, the median age was 45.60 years old (range 31-65 years) and 29.09% of these patients were post-menopause (n = 16). Most patients were T1 stage (65.45%) or N0 stage (70.91%). 80% of patients were ER-positive, 67.27% PR positive, and 61.82% HER2 negative. At the median follow-up of 9.25 years, RNF was 0% and IBTR occurred in only one patient (1.82%) to the chest wall. Except for one patient (1.82%) had DM to lung and pleura and died from disease progression, the remaining patients were alive at the end of the 10-year follow-up. The 10-year DFS and OS were 94.55 and 98.18%. One patient (1.82%) was diagnosed with endometrial cancer after PBI. Except for 9 patients who declined the cosmetic assessment, the rest of the 46 patients (83.64%) were all rated as good and well-satisfied with the appearance of the irradiated breast. No breast retraction and fibrosis were observed in any of the patients. Additionally, only 4 patients experienced grade 1 late toxicity (7.28%). None had grade 3 or higher late toxicity.

Conclusion

This is the first study to report the 10-year results of PBI after breast-conserving surgery in Chinese patients. Our study suggested that PBI had durable local control and maintained good cosmetic outcomes with minimal late toxicity at long term follow up for the early stage breast cancer patients.

Preliminary Results of a Randomized Study on Postmenopausal Women With Early Stage Breast Cancer: Adjuvant Hypofractionated Whole Breast Irradiation Versus Accelerated Partial Breast Irradiation (HYPAB Trial)

BACKGROUND

The purpose of this study was to report preliminary data of a randomized phase III trial comparing hypofractionated whole breast irradiation (HWBI) and accelerated partial breast irradiation (APBI) using volumetric modulated arc therapy (VMAT).

MATERIAL AND METHODS

The HYPAB trial enrolled postmenopausal women with biopsy-proven infiltrating breast cancer, clinically negative axilla, single T1 to T2 tumors, who were treated with breast-conserving surgery. Patients were randomized 1:1 after surgery to HWBI (40.5 Gy whole breast, 48.0 Gy to surgical bed, 15 fractions over 3 weeks) or APBI (30 Gy delivered in 5 fractions of 6 Gy given on alternate days on the surgical bed). Cosmetic outcome was the primary end point of the study.

RESULTS

A total of 172 patients were enrolled. After a median follow-up of 36 months, 5 local failures and 3 locoregional failures were recorded, with no difference between the 2 treatment arms. Use of HWBI as compared with APBI was significantly correlated with increased incidence of overall (62% vs. 14%; P < .001) and grade 2 (18% vs. 1%; P < .001) acute skin toxicity. APBI was correlated with a lower incidence of overall late toxicity as compared with HWBI (18% vs. 41%; P = .001), but no significant difference was found in term of occurrence of grade 2 events (1% vs. 4%; P = NS). At comparative assessment between baseline and post-radiotherapy evaluation, impairment in cosmetic outcome was reported in 19 (11%) patients. Owing to premature closure of the study, no per-protocol comparison between the treatment arms was performed.

CONCLUSION

APBI with the VMAT technique is safe and feasible, with lower acute toxicity when compared with HWBI.

Characterization and registration of 3D ultrasound for use in permanent breast seed implant brachytherapy treatment planning

PURPOSE

Permanent breast seed implant (PBSI) brachytherapy is a novel technique for early-stage breast cancer. Computed tomography (CT) images are used for treatment planning and freehand 2D ultrasound for implant guidance. The multimodality imaging approach leads to discrepancies in target identification. To address this, a prototype 3D ultrasound (3DUS) system was recently developed for PBSI. In this study, we characterize the 3DUS system performance, establish QA baselines, and develop and test a method to register 3DUS images to CT images for PBSI planning.

METHODS AND MATERIALS

3DUS system performance was characterized by testing distance and volume measurement accuracy, and needle template alignment accuracy. 3DUS-CT registration was achieved through point-based registration using a 3D-printed model designed and constructed to provide visible landmarks on both images and tested on an in-house made gel breast phantom.

RESULTS

The 3DUS system mean distance measurement accuracy was within 1% in axial, lateral, and elevational directions. A volumetric error of 3% was observed. The mean needle template alignment error was 1.0° ± 0.3 ° and 1.3 ± 0.5 mm. The mean 3DUS-CT registration error was within 3 mm when imaging at the breast centre or across all breast quadrants.

CONCLUSIONS

This study provided baseline data to characterize the performance of a prototype 3DUS system for PBSI planning and developed and tested a method to obtain accurate 3DUS-CT image registration for PBSI planning. Future work will focus on system validation and characterization in a clinical context as well as the assessment of impact on treatment plans.

DEGRO practical guideline for partial-breast irradiation

PURPOSE

This consensus statement from the Breast Cancer Working Group of the German Society for Radiation Oncology (DEGRO) aims to define practical guidelines for accelerated partial-breast irradiation (APBI).

METHODS

Recent recommendations for relevant aspects of APBI were summarized and a panel of experts reviewed all the relevant literature. Panel members of the DEGRO experts participated in a series of conferences, supplemented their clinical experience, performed a literature review, and formulated recommendations for implementing APBI in clinical routine, focusing on patient selection, target definition, and treatment technique.

RESULTS

Appropriate patient selection, target definition for different APBI techniques, and basic rules for appropriate APBI techniques for clinical routine outside of clinical trials are described. Detailed recommendations for APBI in daily practice, including dose constraints, are given.

CONCLUSION

Guidelines are mandatory to assure optimal results of APBI using different techniques.

Health-Related Quality of Life and Patient-Reported Outcomes in Radiation Oncology Clinical Trials

OPINION STATEMENT

The importance of assessing health-related quality of life (HRQoL) and patient-reported outcomes (PROs) is now well recognized as an essential measure when evaluating the effectiveness of new cancer therapies. Quality of life measures provide for a multi-dimensional understanding of the impact of cancer treatment on measures ranging from functional, psychological, and social aspects of a patient's health. Patient-reported outcomes provide for an assessment of physical and functional symptoms that are directly elicited from patients. Collection of PROs and HRQoL data has been shown to not only be feasible but also provide for reliable measures that correlate with established outcomes measures better than clinician-scored toxicities. The importance of HRQoL measures has been emphasized by both patients and clinicians, as well as policy makers and regulatory bodies. Given the benefits associated with measuring HRQoL and PROs in oncology clinical trials, it is increasingly important to establish methods to effectively incorporate PROs and HRQoL measures into routine clinical practice.

Long term survival and local control outcomes from single dose targeted intraoperative radiotherapy during lumpectomy (TARGIT-IORT) for early breast cancer: TARGIT-A randomised clinical trial

OBJECTIVE

To determine whether risk adapted intraoperative radiotherapy, delivered as a single dose during lumpectomy, can effectively replace postoperative whole breast external beam radiotherapy for early breast cancer.

DESIGN

Prospective, open label, randomised controlled clinical trial.

SETTING

32 centres in 10 countries in the United Kingdom, Europe, Australia, the United States, and Canada.

PARTICIPANTS

2298 women aged 45 years and older with invasive ductal carcinoma up to 3.5 cm in size, cN0-N1, eligible for breast conservation and randomised before lumpectomy (1:1 ratio, blocks stratified by centre) to either risk adapted targeted intraoperative radiotherapy (TARGIT-IORT) or external beam radiotherapy (EBRT).

INTERVENTIONS

Random allocation was to the EBRT arm, which consisted of a standard daily fractionated course (three to six weeks) of whole breast radiotherapy, or the TARGIT-IORT arm. TARGIT-IORT was given immediately after lumpectomy under the same anaesthetic and was the only radiotherapy for most patients (around 80%). TARGIT-IORT was supplemented by EBRT when postoperative histopathology found unsuspected higher risk factors (around 20% of patients).

MAIN OUTCOME MEASURES

Non-inferiority with a margin of 2.5% for the absolute difference between the five year local recurrence rates of the two arms, and long term survival outcomes.

RESULTS

Between 24 March 2000 and 25 June 2012, 1140 patients were randomised to TARGIT-IORT and 1158 to EBRT. TARGIT-IORT was non-inferior to EBRT: the local recurrence risk at five year complete follow-up was 2.11% for TARGIT-IORT compared with 0.95% for EBRT (difference 1.16%, 90% confidence interval 0.32 to 1.99). In the first five years, 13 additional local recurrences were reported (24/1140 v 11/1158) but 14 fewer deaths (42/1140 v 56/1158) for TARGIT-IORT compared with EBRT. With long term follow-up (median 8.6 years, maximum 18.90 years, interquartile range 7.0-10.6) no statistically significant difference was found for local recurrence-free survival (hazard ratio 1.13, 95% confidence interval 0.91 to 1.41, P=0.28), mastectomy-free survival (0.96, 0.78 to 1.19, P=0.74), distant disease-free survival (0.88, 0.69 to 1.12, P=0.30), overall survival (0.82, 0.63 to 1.05, P=0.13), and breast cancer mortality (1.12, 0.78 to 1.60, P=0.54). Mortality from other causes was significantly lower (0.59, 0.40 to 0.86, P=0.005).

CONCLUSION

For patients with early breast cancer who met our trial selection criteria, risk adapted immediate single dose TARGIT-IORT during lumpectomy was an effective alternative to EBRT, with comparable long term efficacy for cancer control and lower non-breast cancer mortality. TARGIT-IORT should be discussed with eligible patients when breast conserving surgery is planned.

TRIAL REGISTRATION

ISRCTN34086741, NCT00983684.