First results of the randomised UK FAST Trial of radiotherapy hypofractionation for treatment of early breast cancer (CRUKE/04/015)

Geriatric determinants of curative radiotherapy scheme choice for older adults with breast cancer treatment compliance and tolerance: Results from the GERABEL study

INTRODUCTION

Chronological and functional aging complicates care in older patients, and therapeutic decisions need to consider individual needs to minimise morbidity and mortality. Therapeutic decisions should be guided by a multidisciplinary geriatric assessment, allowing a complete assessment of physical and functional performance. In this context, the GERABEL study aimed to orientate the irradiation strategy based on a detailed oncogeriatric assessment in women more than 70 years old with breast cancer.

MATERIALS AND METHODS

This was a multicentre clinical trial conducted between January 2017 and June 2021. The oncogeriatric assessment comprised seven questionnaires (activities of daily living [ADL], instrumental ADL, Mini-Mental State Examination, mini Geriatric Depression Scale, Mini-Nutritional Assessment, Cumulative Illness Rating Scale-Geriatric, and Timed Up and Go) to determine a predictive score. Irradiation regimen was assigned according to oncogeriatric score: normofractionated - NF (score range, 160-200), hypofractionated - HF (score range, 159-120), or high-dose hypofractionated - HDHF (score ≤ 119). Endpoints were the overall tolerance to treatment, using the oncogeriatric score as a proxy at six months post-treatment, and compliance.

RESULTS

After oncogeriatric assessment at baseline, 177 patients were treated with a NF regimen, 24 with a HF regimen, and four with a HDHF regimen. Tolerance was excellent in the three groups, as no decrease of more than 20 % in the oncogeriatric score was noted at six months post-treatment. More generally, 68 % and 73 % of patients reported an improvement of the oncogeriatric score at two months and six months post-treatment, respectively. Only four treatment interruptions were observed and quality-of-life was well-conserved. In the hypo fractionated groups, short-term toxicities were not increased and no impact was noted on compliance.

DISCUSSION

Decision-making guidance for irradiation schemes in breast cancer according to oncogeriatric determinants was successful in older patients, who tolerated treatment well and, overall, had a preserved general condition.

Randomised controlled trials on radiation dose fractionation in breast cancer: systematic review and meta-analysis with emphasis on side effects and cosmesis

OBJECTIVE

To provide a comprehensive assessment of various fractionation schemes in radiation therapy for breast cancer, with a focus on side effects, cosmesis, quality of life, risks of recurrence, and survival outcomes.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Ovid MEDLINE, Embase, and Cochrane Central Register of Controlled Trials (from inception to 23 October 2023).

STUDY SELECTION

Included studies were randomised controlled trials focusing on conventional fractionation (CF; daily fractions of 1.8-2 Gy, reaching a total dose of 50-50.4 Gy over 5-6 weeks), moderate hypofractionation (MHF; fraction sizes of 2.65-3.3 Gy for 13-16 fractions over 3-5 weeks), and/or ultra-hypofractionation (UHF; schedule of only 5 fractions).

DATA EXTRACTION

Two independent investigators screened studies and extracted data. Risk of bias and quality of evidence were assessed using the Cochrane Collaboration's tool and the GRADE (Grading of Recommendations, Assessment, Development, and Evaluations) approach, respectively.

DATA SYNTHESIS

Pooled risk ratios (RRs) and hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated using a random effects model. Heterogeneity was analysed using Cochran's Q test and I2 statistic. Network meta-analysis was used to integrate all available evidence.

MAIN OUTCOME MEASURES

The pre-specified primary outcome was grade ≥2 acute radiation dermatitis and late radiation therapy related side effects; secondary outcomes included cosmesis, quality of life, recurrence, and survival metrics.

RESULTS

From 1754 studies, 59 articles representing 35 trials (20 237 patients) were assessed; 21.6% of outcomes showed low risk of bias, whereas 78.4% had some concerns or high risk, particularly in outcome measurement (47.4%). The RR for grade ≥2 acute radiation dermatitis for MHF compared with CF was 0.54 (95% CI 0.49 to 0.61; P<0.001) and 0.68 (0.49 to 0.93; P=0.02) following breast conserving therapy and mastectomy, respectively. Hyperpigmentation and grade ≥2 breast shrinkage were less frequent after MHF than after CF, with RRs of 0.77 (0.62 to 0.95; P=0.02) and 0.92 (0.85 to 0.99; P=0.03), respectively, in the combined breast conserving therapy and mastectomy population. However, in the breast conserving therapy only trials, these differences in hyperpigmentation (RR 0.79, 0.60 to 1.03; P=0.08) and breast shrinkage (0.94, 0.83 to 1.07; P=0.35) were not statistically significant. The RR for grade ≥2 acute radiation dermatitis for UHF compared with MHF was 0.85 (0.47 to 1.55; P=0.60) for breast conserving therapy and mastectomy patients combined. MHF was associated with improved cosmesis and quality of life compared with CF, whereas data on UHF were less conclusive. Survival and recurrence outcomes were similar between UHF, MHF, and CF.

CONCLUSIONS

MHF shows improved safety profile, cosmesis, and quality of life compared with CF while maintaining equivalent oncological outcomes. Fewer randomised controlled trials have compared UHF with other fractionation schedules, but its safety and oncological effectiveness seem to be similar with short term follow-up. Given the advantages of reduced treatment time, enhanced convenience for patients, and potential cost effectiveness, MHF and UHF should be considered as preferred options over CF in appropriate clinical settings, with further research needed to solidify these findings.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42023460249.

Hypofractionated Radiation Therapy: A Cross-sectional Survey Study of US Radiation Oncologists

OBJECTIVES

For many malignancies, hypofractionated radiotherapy (HFRT) is an accepted standard associated with decreased treatment time and costs. United States provider beliefs regarding HFRT likely impact its adoption but are poorly studied. We surveyed US-based radiation oncologists (ROs) to gauge HFRT utilization rates for prostate (PC), breast (BC), and rectal cancer (RC) and to characterize the beliefs governing these decisions.

METHODS

From July to October 2021, an anonymized, online survey was electronically distributed to ROs actively practicing in the United States. Demographic and practice characteristic information was collected. Questions assessing rates of offering HFRT for PC, BC, and RC and perceived limitations towards using HFRT were administered.

RESULTS

A total of 203 eligible respondents (72% male, 72% White, 53% nonacademic practice, 69% with 11+ years in practice) were identified. Approximately 50% offered stereotactic body radiation therapy (SBRT) for early/favorable intermediate risk PC. Although >90% of ROs offered whole-breast HFRT for early-stage BC, only 33% offered accelerated partial-breast irradiation (APBI). Overall, 41% of ROs offered short-course neoadjuvant RT for RC. The primary reported barriers to HFRT utilization were lack of data, inexperience, and referring provider concerns.

CONCLUSIONS

HFRT is safe, effective, and beneficial, yet underutilized-particularly prostate SBRT, APBI, and short-course RT for RC. Skills retraining and education of ROs and referring providers may increase utilization rates.

Radiation-induced dermatitis among breast cancer patients undergoing adjuvant radiotherapy in Ghana

The aim of the study was to investigate radiation-induced epidermal desquamation among breast cancer patients undergoing radiotherapy with 6MV linac and Co-60 teletherapy units. METHOD: Quantitative data was collected using self-administered closed ended questionnaires addressing the desquamation in relation to some patient-and treatment-related factors. The Radiation Therapy Oncology Group (RTOG) criteria for acute skin toxicity was used to grade the toxicity. Chi square and logistic regression analyses were respectively used to test statistical significance and evaluate the effects of the various factors on radiation induced epidermal desquamation RESULTS: Majority of the participants had high BMIs (overweight: 39.5 %; obese: 50 %). Patients with BMI ≥ 25 kg/m2 presented with wet desquamation (RTOG grade 2). A chi-square analysis showed a significant difference (p = 0.02) between BMI and severity of desquamation. There was no significant difference between type of treatment machine and cumulative incidence dose of desquamation (p= 0.251). The logistic regression analysis showed that patients who had undergone mastectomy (OR = 0.562) were less likely to develop wet desquamation (RTOG grade 2) on the Co-60 machine within the 20-30 Gy threshold (OR=0.981) compared to those on the linear accelerator. Patients with lower BMI (OR = 0.412,[ < 25 vs ≥30]; OR = 0.286, [25-29.9 vs ≥30]) were also less likely to develop wet desquamation compared to those with higher BMI. CONCLUSION: Radiation-induced epidermal desquamation is a common side effect of breast cancer patients undergoing radiotherapy. BMI has an effect on the severity of desquamation experienced during breast irradiation.

Women's Preferences for Hypofractionated Radiation Therapy for Treatment of Early-Stage Breast Cancer: A Discrete Choice Experiment

PURPOSE

The primary treatment recommended for early-stage breast cancer is breast conserving surgery followed by external beam radiation therapy of the whole breast. Previously, radiation therapy for early-stage breast cancer was given using more fractions over longer durations. Guidelines support treatments with fewer fractions over a shorter time (hypofractionated radiation therapy). This study aimed to understand women's preferences for different features of treatments for early-stage breast cancer.

METHODS AND MATERIALS

A discrete choice experiment with 12 choice tasks was conducted, describing the treatments by extent of surgery, duration of radiation treatment, need to relocate for treatment, local side effects, changes in breast appearance, costs, and difficulty with daily activities during and after treatment. Participants were women with breast cancer and from the general population. Mixed logit analyses were conducted and trade-offs between attributes estimated.

RESULTS

Four hundred twenty respondents completed the discrete choice experiment. The relative importance of attributes varied by respondent characteristics; the most influential attribute for younger women was type of surgery (breast conserving surgery). Type of surgery did not influence older women's preferences. Shorter treatment duration, avoiding relocation, fewer local side effects, and less difficulty with daily activities all positively influenced treatment preference. Younger women were willing to accept 32 to 40 days of radiation treatment before a treatment that included mastectomy was potentially acceptable.

CONCLUSIONS

Attributes of treatment such as duration, need for relocation, side effects, and effects on normal daily activities during and after treatment significantly influenced women's preference for treatment, including surgery. Our findings have the potential for real impact for patients and services including supporting one-on-one clinical discussions, supporting program and patient resource development, and informing service funding, organization, and delivery.

Ultra-hypofractionated one-week locoregional radiotherapy for patients with early breast cancer: Acute toxicity results

Purpose

Moderate hypofractionated radiotherapy is the standard of care for all patients with breast cancer, irrespective of stage or prior treatments. While extreme hypofractionation is accepted for early-stage tumours, its application in irradiating locoregional lymph nodes remains controversial.

Materials and methods

A prospective registry analysis from July 2020 to September 2023 included 276 patients with early-stage breast cancer treated with one-week ultra-hypofractionation (UHF) at 26 Gy in 5 fractions on the whole breast (58.3 %) or thoracic wall (41.7 %) and ipsilateral regional lymph nodes and simultaneous integrated boost (58.3 %). Primary endpoint was assessment of acute adverse events (AEs). Secondarily, onset of early-delayed toxicity was assessed. A minimum 6-month follow-up was required for assessing potential treatment-related early-delayed complications. Acute or late complications attributable to treatment were assessed at inclusion using the Common Terminology Criteria for Adverse Events (CTCAE) v5.0 criteria.

Results

With a median follow-up of 19 months (range 1-49 months), 159 (57.6 %) patients reported AEs, predominantly grade (G) 1 (n = 139, 50.4 %) and G2 (n = 20, 7.8 %). Skin acute toxicity was common (G1/2: 134, G3: 14), while breast oedema occurred in 10 patients (G1: 9, G2: 1), and 15.9 % reported breast pain (G1: 42, G2: 2). Ipsilateral arm oedema was observed in 1.8 % patients. For patients with a follow-up beyond 6 months (n = 213), 23.4 % patients reported G1/G2 skin AEs, 8.8 % had G1/G2 breast/chest wall oedema, and 8.9 % experienced arm lymphedema. There were no cases of brachial plexopathy or G3 toxicity in this group of patients.

Conclusions

One-week UHF adjuvant locoregional radiation is well-tolerated, displaying low-toxicity profiles comparable to other studies using similar irradiation schedules.

Use of Radiation Therapy for the Treatment of Breast Cancer in 2019 Versus 2020

Purpose

The COVID-19 pandemic disrupted medical care. Little is known about how radiation therapy (RT) ordering behavior changed during the pandemic. This study examined (1) whether there was a change in the rate at which orders for lumpectomy were followed by orders for RT and (2) whether there was a change in the percentage of RT orders for hypofractionated (HF) RT rather than conventionally fractionated (CF) RT.

Methods and Materials

Prior authorization order data from 2019 and 2020, pertaining to patients with commercial and Medicare Advantage health plans, were reviewed to determine whether patients had an order for RT in the 90 days after lumpectomy and if it was for CF or HF RT. Univariate analyses were conducted using χ2 tests, and adjusted analyses were conducted using multivariate logistic regression, controlling for patient age, urbanicity, local median income, region, if the lumpectomy facility was academic, and if the lumpectomy facility was a hospital.

Results

In 2019, 47.7% of included lumpectomy orders (2200/4610) were followed by an RT order within 90 days, in contrast to 45.6% (1944/4263) in 2020 (P = .048). Of the RT orders meeting this study's definition of CF or HF, 75.3% of orders placed in 2019 (1387/1843) and 79.0% of orders placed in 2020 (1261/1597) were for HF (P = .011). Adjusted analysis found patients receiving a lumpectomy order in the first quarter of 2020 had significantly reduced odds (odds ratio, 0.84; 95% CI, 0.71-0.99) of receiving an order for RT after lumpectomy, relative to those with orders placed in the first quarter of 2019. Adjusted analysis likewise found significant evidence of increased use of HF RT during the pandemic.

Conclusions

In the population examined, physicians were less likely to order RT after lumpectomy in 2020 than in 2019, and if they did, were more likely to order HF RT.

In vivo dose measurements for tangential field-in-field ultra-hypofractionated breast radiotherapy

INTRODUCTION

Ultra-hypofractionated radiotherapy (UHF-RT) mandates more accuracy in each part of the treatment cycle to maximize cure rates and minimize toxicities. In vivo dosimetry is a direct method for verifying overall treatment accuracy. This study evaluated uncertainties in the delivered dose of Hypofractionated (HF) and UHF Whole Breast Irradiation (WBI) and to analyze the accuracy of the workflow to pave the way for a wide-scale use of UHF-RT.

METHODS

Thirty-three breast cancer cases, including 16 HF-WBI and 17 UHF-WBI were treated with 3D conformal Radiotherapy (3D-CRT), where 79 fields were analyzed for dose verification. The measurement point was set at the beam entrance (1.5 cm depth). The expected dose at Dmax was calculated via TPS. Before in vivo measurements, diode detectors were tested and calibrated. We developed initial validation measurements for UHF-RT on an anthropomorphic breast phantom for the first time.

RESULTS

For RANDO phantom, the percentage difference between measured and calculated doses showed an average of -0.52 ± 5.4%, in addition to an excellent dose reproducibility within 0.6%. The overall in vivo measurements for studied cases showed that 83.5% of the measured doses were within ±5% and only 1.8% of the measured doses were greater than ±10% of the calculated doses. The percentage accuracy was slightly larger for UHF cohort (84.2%) compared to HF cohort (83.2%). The maximum percentage difference between them was less than 1%.

CONCLUSION

Breast in vivo dosimetry is an adequate tool for treatment verification that improves the accuracy of the treatment cycle. UHF-RT may contribute in reducing the long waiting lists, increasing patient convenience, and saving the available resources for breast cancer patients.

Large scale experience of two ultrahypofractionated 5 fractions regimes after breast conserving surgery from a single centre

PURPOSE

Ultra-hypofractionation breast radiotherapy is a safe alternative to moderate hypofractionation. This study reports the results of two ultrahypofractionated regimens used in clinical practice in a high-volume radiotherapy center in terms of efficacy and of tolerance.

METHODS

we included all patients treated in an adjuvant setting with five fractions after breast conserving surgery (BCS), for a histologically-confirmed invasive or in situ breast carcinoma. Radiotherapy regimens after BCS were either a 5-week schedule with 5 weekly fractions of 5,7 Gy or a one-week schedule with 5 daily fractions of 5,2 Gy. Adverse events were recorded and local-relapse free survival (LRFS), locoregional-relapse free survival (LRRFS), metastasis-free survival (MFS), for breast-cancer specific survival (BCSS) and overall survival (OS) were evaluated.

RESULTS

Between December 2014 and December 2022, 396 patients (400 breasts) were treated with ultrahypofractionated radiotherapy. Five-year LRFS was 98.8% (95% confidence interval: 97.1%-100%), and 5-year OS was 96.0% (95%CI: 92.6-99.5%). Age was statistically associated with OS in univariate analysis (HR: 1.16, 95%CI: 1.04-1.42, p = .01). Four patients (1.0%) experienced acute grade 3 radiation-induced adverse events, and 8 patients (2.3%) acute grade 2 toxicities. Twenty-three patients (5.8%) experienced late toxicity, all of them being graded as grade 1. The use of the 5.7 Gy-weekly-fraction regimen and the delivery of a tumor bed boost were significantly associated with acute radiodermatitis (p < .01; p = .02; respectively) and late fibrosis (p < .01; p = .049; respectively).

CONCLUSIONS

ultrahypofractionated radiotherapy was associated with an excellent tumor control rate in our 'real-life' cohort with low-risk breast cancer patients. However, delivery of a tumor bed boost and using weekly 5.7-Gy fractions were associated with an increased risk of acute and late cutaneous toxicities.

One versus three weeks hypofractionated whole breast radiotherapy for early breast cancer treatment: the FAST-Forward phase III RCT

Background

FAST-Forward aimed to identify a 5-fraction schedule of adjuvant radiotherapy delivered in 1 week that was non-inferior in terms of local cancer control and as safe as the standard 15-fraction regimen after primary surgery for early breast cancer. Published acute toxicity and 5-year results are presented here with other aspects of the trial.

Design

Multicentre phase III non-inferiority trial. Patients with invasive carcinoma of the breast (pT1-3pN0-1M0) after breast conservation surgery or mastectomy randomised (1 : 1 : 1) to 40 Gy in 15 fractions (3 weeks), 27 Gy or 26 Gy in 5 fractions (1 week) whole breast/chest wall (Main Trial). Primary endpoint was ipsilateral breast tumour relapse; assuming 2% 5-year incidence for 40 Gy, non-inferiority pre-defined as < 1.6% excess for 5-fraction schedules (critical hazard ratio = 1.81). Normal tissue effects were assessed independently by clinicians, patients and photographs.

Sub-studies

Two acute skin toxicity sub-studies were undertaken to confirm safety of the test schedules. Primary endpoint was proportion of patients with grade ≥ 3 acute breast skin toxicity at any time from the start of radiotherapy to 4 weeks after completion. Nodal Sub-Study patients had breast/chest wall plus axillary radiotherapy testing the same three schedules, reduced to the 40 and 26 Gy groups on amendment, with the primary endpoint of 5-year patient-reported arm/hand swelling.

Limitations

A sequential hypofractionated or simultaneous integrated boost has not been studied.

Participants

Ninety-seven UK centres recruited 4096 patients (1361:40 Gy, 1367:27 Gy, 1368:26 Gy) into the Main Trial from November 2011 to June 2014. The Nodal Sub-Study recruited an additional 469 patients from 50 UK centres. One hundred and ninety and 162 Main Trial patients were included in the acute toxicity sub-studies.

Results

Acute toxicity sub-studies evaluable patients: (1) acute grade 3 Radiation Therapy Oncology Group toxicity reported in 40 Gy/15 fractions 6/44 (13.6%); 27 Gy/5 fractions 5/51 (9.8%); 26 Gy/5 fractions 3/52 (5.8%). (2) Grade 3 common toxicity criteria for adverse effects toxicity reported for one patient. At 71-month median follow-up in the Main Trial, 79 ipsilateral breast tumour relapse events (40 Gy: 31, 27 Gy: 27, 26 Gy: 21); hazard ratios (95% confidence interval) versus 40 Gy were 27 Gy: 0.86 (0.51 to 1.44), 26 Gy: 0.67 (0.38 to 1.16). With 2.1% (1.4 to 3.1) 5-year incidence ipsilateral breast tumour relapse after 40 Gy, estimated absolute differences versus 40 Gy (non-inferiority test) were -0.3% (-1.0-0.9) for 27 Gy (p = 0.0022) and -0.7% (-1.3-0.3) for 26 Gy (p = 0.00019). Five-year prevalence of any clinician-assessed moderate/marked breast normal tissue effects was 40 Gy: 98/986 (9.9%), 27 Gy: 155/1005 (15.4%), 26 Gy: 121/1020 (11.9%). Across all clinician assessments from 1 to 5 years, odds ratios versus 40 Gy were 1.55 (1.32 to 1.83; p < 0.0001) for 27 Gy and 1.12 (0.94-1.34; p = 0.20) for 26 Gy. Patient and photographic assessments showed higher normal tissue effects risk for 27 Gy versus 40 Gy but not for 26 Gy. Nodal Sub-Study reported no arm/hand swelling in 80% and 77% in 40 Gy and 26 Gy at baseline, and 73% and 76% at 24 months. The prevalence of moderate/marked arm/hand swelling at 24 months was 10% versus 7% for 40 Gy compared with 26 Gy.

Interpretation

Five-year local tumour incidence and normal tissue effects prevalence show 26 Gy in 5 fractions in 1 week is a safe and effective alternative to 40 Gy in 15 fractions for patients prescribed adjuvant local radiotherapy after primary surgery for early-stage breast cancer.

Future work

Ten-year Main Trial follow-up is essential. Inclusion in hypofractionation meta-analysis ongoing. A future hypofractionated boost trial is strongly supported.

Trial registration

FAST-Forward was sponsored by The Institute of Cancer Research and was registered as ISRCTN19906132.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: 09/01/47) and is published in full in Health Technology Assessment; Vol. 27, No. 25. See the NIHR Funding and Awards website for further award information.

Dosimetric and radiobiological comparison between conventional and hypofractionated breast treatment plans using the Halcyon system

Purpose

The objective of this research is to compare the efficacy of conventional and hypofractionated radiotherapy treatment plans for breast cancer patients, with a specific focus on the unique features of the Halcyon system.

Methods and materials

The study collected and analyzed dose volume histogram (DVH) data for two groups of treatment plans implemented using the Halcyon system. The first group consisted of 19 patients who received conventional fractionated (CF) treatment with a total dose of 50 Gy in 25 fractions, while the second group comprised 9 patients who received hypofractionated (HF) treatment with a total dose of 42.56 Gy in 16 fractions. The DVH data was used to calculate various parameters, including tumor control probability (TCP), normal tissue complication probability (NTCP), and equivalent uniform dose (EUD), using radiobiological models.

Results

The results indicated that the CF plan resulted in higher TCP but lower NTCP for the lungs compared to the HF plan. The EUD for the HF plan was approximately 49 Gy (114% of its total dose) while that for the CF plan was around 53 Gy (107% of its total dose).

Conclusions

The analysis suggests that while the CF plan is better at controlling tumors, it is not as effective as the HF plan in minimizing side effects. Additionally, it is suggested that there may be an optimal configuration for the HF plan that can provide the same or higher EUD than the CF plan.

[Five-fraction radiotherapy for breast cancer]

Extreme hypofractionation in adjuvant breast radiotherapy currently generates a lot of interest. We propose here a synthesis of hypofractionation trials and present the DESTHE COL and DESTHE GR projects, encouraged by the French National Cancer Institute (INCa), which experiment care pathways in order to deploy effective strategies to de-escalate the therapeutics and to reduce sequelae after cancer treatment.

Advances in Radiotherapy for Breast Cancer

Breast cancer is the most prevalent cancer in women, and the second leading cause of cancer death in women in the United States. Radiation therapy is an important component in the multimodal management of breast cancer, including early stage and locally advanced breast cancers, as well as metastatic cases. Breast cancer radiation therapy has seen significant advancements over the past 20 years. This article discusses the latest advances in the radiotherapeutic management of breast cancer, especially focusing on the technological advances in radiation treatment planning and techniques that have exploited the understanding of radiation biology.

Evaluation of the ESMO-Magnitude of Clinical Benefit Scale version 1.1 (ESMO-MCBS v1.1) for adjuvant radiotherapy in breast cancer

BACKGROUND

The European Society of Medical Oncology (ESMO) has suggested using the ESMO-Magnitude of Clinical Benefit Scale (MCBS) to grade the magnitude of clinical benefit of cancer therapies. This approach has not been applied to radiation therapy (RT) yet. We applied the ESMO-MCBS to experiences describing the use of RT to assess (1) the 'scoreability' of the data, (2) evaluate the reasonableness of the grades for clinical benefit and (3) identify potential shortcomings in the current version of the ESMO-MCBS in its applicability to RT.

MATERIALS AND METHODS

We applied the ESMO-MCBS v1.1 to a selection of studies in radiotherapy that had been identified as references in the development of American Society for Radiation Oncology (ASTRO) evidence-based guidelines on whole breast radiation. Of the 112 cited references, we identified a subset of 16 studies that are amenable to grading using the ESMO-MCBS.

RESULTS

Of the 16 studies reviewed, 3/16 were scoreable with the ESMO tool. Six of 16 studies could not be scored because of shortcomings in the ESMO-MCBS v1.1: (1) in 'non-inferiority studies', there is no credit for improved patient convenience, reduced patient burden or improved cosmesis; (2) in 'superiority studies' evaluating local control as a primary endpoint, there is no credit for the clinical benefit such as reduced need for further interventions. In 7/16 studies, methodological deficiencies in the conduct and reporting were identified.

CONCLUSIONS

This study represents a first step in determining the utility of the ESMO-MCBS in the evaluation of clinical benefit in radiotherapy. Important shortcomings were identified that would need to be addressed in developing a version of the ESMO-MCBS that can be robustly applied to radiotherapy treatments. Optimization of the ESMO-MCBS instrument will proceed to enable assessment of value in radiotherapy.

Hypofractionation: The standard for external beam breast irradiation

This overview provides the historical perspective of external beam breast hypofractionation over the last 50 years. It highlights the serious harm suffered by patients with breast cancer in the 1970's and 1980's because of new hypofractionation regimens based on a theoretical radiobiology model being adopted into clinical practice to solve a resource issue without testing within clinical trials and without the essential radiotherapy quality assurance. It then describes the high-quality clinical trials comparing 3-week with 5-week standard of care regimens that were initiated based on a strong scientific rationale for hypofractionation in breast cancer. Today, there are still challenges with universal implementation of the results of these moderate hypofractionation studies, but there is now a substantial body of evidence to support 3-week breast radiotherapy with several large randomised trials still to report. The limit of breast hypofractionation is then explored and randomised trials investigating 1-week radiotherapy are described. This approach is now standard of care in many countries for whole or partial breast radiotherapy and chest wall radiotherapy without immediate reconstruction. It also has the advantage of reducing burden of treatment for patients and providing cost-effective care. Further research is needed to establish the safety and efficacy of 1-week breast locoregional radiotherapy and following immediate breast reconstruction. In addition, clinical studies are required to determine how a tumour bed boost for patients with breast cancer at higher risk of relapse can be incorporated simultaneously into a 1-week radiotherapy schedule. As such, the breast hypofractionation story is still unfolding.

Prediction of pathologic complete response after single-dose MR-guided partial breast irradiation in low-risk breast cancer patients: the ABLATIVE-2 trial-a study protocol

BACKGROUND

Partial breast irradiation (PBI) is standard of care in low-risk breast cancer patients after breast-conserving surgery (BCS). Pre-operative PBI can result in tumor downstaging and more precise target definition possibly resulting in less treatment-related toxicity. This study aims to assess the pathologic complete response (pCR) rate one year after MR-guided single-dose pre-operative PBI in low-risk breast cancer patients.

METHODS

The ABLATIVE-2 trial is a multicenter prospective single-arm trial using single-dose ablative PBI in low-risk breast cancer patients. Patients ≥ 50 years with non-lobular invasive breast cancer ≤ 2 cm, grade 1 or 2, estrogen receptor-positive, HER2-negative, and tumor-negative sentinel node procedure are eligible. A total of 100 patients will be enrolled. PBI treatment planning will be performed using a radiotherapy planning CT and -MRI in treatment position. The treatment delivery will take place on a conventional or MR-guided linear accelerator. The prescribed radiotherapy dose is a single dose of 20 Gy to the tumor, and 15 Gy to the 2 cm of breast tissue surrounding the tumor. Follow-up MRIs, scheduled at baseline, 2 weeks, 3, 6, 9, and 12 months after PBI, are combined with liquid biopsies to identify biomarkers for pCR prediction. BCS will be performed 12 months after radiotherapy or after 6 months, if MRI does not show a radiologic complete response. The primary endpoint is the pCR rate after PBI. Secondary endpoints are radiologic response, toxicity, quality of life, cosmetic outcome, patient distress, oncological outcomes, and the evaluation of biomarkers in liquid biopsies and tumor tissue. Patients will be followed up to 10 years after radiation therapy.

DISCUSSION

This trial will investigate the pathological tumor response after pre-operative single-dose PBI after 12 months in patients with low-risk breast cancer. In comparison with previous trial outcomes, a longer interval between PBI and BCS of 12 months is expected to increase the pCR rate of 42% after 6-8 months. In addition, response monitoring using MRI and biomarkers will help to predict pCR. Accurate pCR prediction will allow omission of surgery in future patients.

TRIAL REGISTRATION

The trial was registered prospectively on April 28th 2022 at clinicaltrials.gov (NCT05350722).

Atrial fibrillation and breast cancer—Vicious twins? A systematic review and meta-analysis

Background

Epidemiological studies suggest a bidirectional association between atrial fibrillation and breast cancer. This study aimed to conduct a meta-analysis to elucidate the prevalence of atrial fibrillation among breast cancer patients, and the bidirectional association between atrial fibrillation and breast cancer.

Methods

PubMed, the Cochrane Library, and Embase were searched to identify studies reporting the prevalence, incidence, and bidirectional association between atrial fibrillation and breast cancer. The study was registered with PROSPERO (CRD42022313251). Levels of evidence and recommendations were assessed by the Grading of Recommendations Assessment, Development and Evaluation (GRADE).

Results

Twenty-three studies (17 retrospective cohort studies, 5 case-control studies and 1 cross-sectional study) involving 8,537,551 participants were included. Among patients with breast cancer, the prevalence of atrial fibrillation was 3% (11 studies; 95% CI: 0.6 to 7.1%) and the incidence was 2.7% (6 studies; 95% CI: 1.1 to 4.9%). Breast cancer was associated with increased risk of atrial fibrillation (5 studies; hazard ratio [HR]: 1.43, 95% CI: 1.12 to 1.82, I2 = 98%). Atrial fibrillation was also significantly associated elevated risk of breast cancer (5 studies HR: 1.18, 95% CI: 1.14 to 1.22, I2 = 0%). Grade assessment shown low certainty of the evidence for the risk of atrial fibrillation and moderate certainty of the evidence for the risk of breast cancer.

Conclusion

Atrial fibrillation is not uncommon in patients with breast cancer and vice versa. There is a bidirectional association between atrial fibrillation (low certainty) and breast cancer (moderate certainty).

Breast cancer heterogeneity and its implication in personalized precision therapy

Breast cancer heterogeneity determines cancer progression, treatment effects, and prognosis. However, the precise mechanism for this heterogeneity remains unknown owing to its complexity. Here, we summarize the origins of breast cancer heterogeneity and its influence on disease progression, recurrence, and therapeutic resistance. We review the possible mechanisms of heterogeneity and the research methods used to analyze it. We also highlight the importance of cell interactions for the origins of breast cancer heterogeneity, which can be further categorized into cooperative and competitive interactions. Finally, we provide new insights into precise individual treatments based on heterogeneity.

Cost-Effectiveness Analysis of Ultra-Hypofractionated Whole Breast Radiation Therapy Alone Versus Hormone Therapy Alone or Combined Treatment for Low-Risk ER-Positive Early Stage Breast Cancer in Women Aged 65 Years and Older

PURPOSE

The optimal management of early-stage, low-risk, hormone-positive breast cancer in older women remains controversial. Recent trials have shown that 5-fraction ultrahypofractionated whole-breast irradiation (U-WBI) has similar outcomes to longer courses, reducing the cost and inconvenience of treatment. We performed a cost-utility analysis to compare U-WBI to hormone therapy alone or their combination.

METHODS AND MATERIALS

We simulated 3 different treatment approaches for women age 65 years or older with pT1-2N0 ER-positive invasive ductal carcinoma treated with lumpectomy with negative margins using a Markov microsimulation model. The strategies were U-WBI performed with a 3-dimensional conformal technique over 5 fractions without a boost ("radiation therapy [RT] alone"), adjuvant hormone therapy (anastrozole for 5 years) without RT ("aromatase-inhibitor [AI] alone"), or the combination of the 2. The combination strategy was calibrated to match trial results, and the relative effectiveness of the RT alone and AI alone strategies were inferred from previous randomized trials. The primary endpoint was the cost-effectiveness of the 3 strategies over a lifetime horizon as measured by the incremental cost-effectiveness ratio (ICER), with a value of $100,000/quality-adjusted life-year deemed "cost-effective."

RESULTS

The model results compared with the prespecified target outcomes. On average, RT alone was the least expensive strategy ($14,775), with AI alone slightly more ($14,998), and combination therapy the costliest ($19,802). RT alone dominated AI alone (the incremental cost-effectiveness ratio [ICER] -$5089). Combination therapy, compared with RT alone, was slightly more expensive than our definition of cost-effective (ICER $113,468) but was cost-effective compared with AI alone (ICER $54,451). Probabilistic sensitivity analysis demonstrated RT alone to be cost-effective in 50% of trials, with combination therapy in 36% and AI alone in 14%.

CONCLUSIONS

U-WBI alone appears the more cost-effective de-escalation strategy for these low-risk patients, compared with AI alone. Combining U-WBI and AI appears more costly but may be preferred by some patients.

Ultra-Hypofractionation for Whole-Breast Irradiation in Early Breast Cancer: Interim Analysis of a Prospective Study

We report on the early clinical outcomes of a prospective series of early breast cancer (EBC) patients treated with ultra-hypofractionated post-operative whole-breast irradiation (WBI) after breast-conserving surgery (BCS) and axillary management. Primary endpoints were patient's compliance and acute toxicity. Secondary endpoints included physician-rated cosmesis and ipsilateral breast tumour recurrence (IBTR). Acute toxicity was evaluated at the end of WBI, 3 weeks and 6 months thereafter, according to the Common Terminology Criteria for Adverse Events (v. 5.0). Patients were treated between September 2021 and May 2022. The treatment schedule for WBI consisted of either 26 Gy in 5 fractions over one week (standard approach) or 28.5 Gy in 5 fractions over 5 weeks (reserved to elders). Inverse planned intensity-modulated radiation therapy (IMRT) was used employing a static technique. A total of 70 patients were treated. Fifty-nine were treated with the 26 Gy/5 fr/1 w and 11 with the 28.5 Gy/5 fr/5 ws schedule. Median age was 67 and 70 in the two groups. Most of the patients had left-sided tumours (53.2%) in the 26 Gy/5 fr/1 w or right-sided lesions (63.6%) in the 28.5 Gy/5 fr/5 ws group. Most of the patients had a clinical T1N0 disease and a pathological pT1pN0(sn) after surgery. Ductal invasive carcinoma was the most frequent histology. Luminal A intrinsic subtyping was most frequent. Most of the patients underwent BCS and sentinel lymph node biopsy and adjuvant endocrine therapy. All patients completed the treatment program as planned. Maximum detected acute skin toxicities were grade 2 erythema (6.7%), grade 2 induration (4.4%), and grade 2 skin colour changes. No early IBTR was observed. Ultra-hypofractionated WBI provides favourable compliance and early clinical outcomes in EBC after BCS in a real-world setting.

[The place of radiotherapy]

Radiation therapy (RT) is a key component of the management of elderly breast cancer patients. However, level I evidence in elderly patients is limited. Patient selection should include comorbidities and geriatric assessment. Advances in radiation planning and delivery are improving target coverage, reducing toxicity, and expanding treatment eligibility. Some alternative techniques, such as treatment in the lateral or prone position, may reduce the risk of toxicity. Shorter cycles of hypofractionated whole breast RT are safe and effective. In some cases, partial breast irradiation may be an option.

Patterns of Care and Utilization of Radiation for Women With Good-Risk Ductal Carcinoma In Situ: A National Cancer Database Analysis

Purpose/objective(s) Lumpectomy followed by whole-breast radiation therapy (WBRT) provides a 50% recurrence rate reduction in ductal carcinoma in situ (DCIS) patients when compared to lumpectomy alone. Certain factors increase the risk of recurrence, including higher nuclear grade, large size, age less than 50, and close margins. RTOG 9804 demonstrated a reduction in local failure after WBRT with the use of adjuvant radiation in women with "good-risk disease" (mammographically detected, measuring less than or equal to 2.5 cm, with a predominant nuclear grade of 1 or 2, and a margin of greater than or equal to 1 cm, or a negative re-excision). The purpose of this study is to retrospectively identify the patterns of care in women with low-risk DCIS utilizing the National Cancer Database (NCDB). We hypothesize that with the utilization of hypofractionation, there may be an increase in the delivery of RT for these "good-risk" patients. Materials/methods The National Cancer Database was queried to identify women treated with lumpectomy for <2.5 cm, nuclear grade 1 or 2 DCIS of the breast from 2004 to 2016. Data were collected regarding age, tumor size, endocrine therapy use, ER receptor status, race, insurance type, and distance from the treatment center. The distance was stratified into quartiles consisting of 0-3.9, 4-8, 8.1-15.8, and > 15.8 miles, respectively. Radiation fractionation was collected and categorized as hypofractionation, standard fractionation, or other if fractionation could not be ascertained. Clinical and patient-related factors were compared between patients who received radiation and those who received no radiation. The frequency distributions between categorical variables were compared using the Chi-square test. Multivariable logistic regression was used to identify covariables that impacted the receipt of radiation. Results The eligibility criteria were met by a total of 12,846 patients. Of those, 6,600 (51.4%) received adjuvant WBRT. On multivariable regression, patients whose tumors were ER (OR 1.24, P<0.001) and those who had not received endocrine therapy (OR 2.24, P<0.001) were more likely to receive WBRT. Factors less likely to receive WBRT included increasing age over 50 (age 50-65 OR 0.83, P<0.001; age>65 OR 0.58, P<0.001), and distance of >15.8 miles (OR 0.78, P<0.001). The fractionation technique was categorized as standard or hypofractionated in 52.2% of patients. Of those, the use of hypofractionation increased from 0.4% in 2004 to 8.9% in 2010 and to 53.8% in 2016. Conclusion This NCDB analysis demonstrated that patients who meet the RTOG 9804 criteria for "good-risk" DCIS are less likely to receive RT as time progresses despite an increase in the utilization of hypofractionation techniques. Overall, slightly more than half of these patients receive adjuvant RT.

HYPORT adjuvant acute toxicity and patient dosimetry quality assurance results - Interim analysis

BACKGROUND

HYPORT adjuvant trial is a randomised phase III open-label noninferiority trial comparing standard moderately hypofractionated 3 week adjuvant radiation therapy in breast cancer with a novel 1-week schedule. The trial was initiated in March 2019 and is open to recruitment with a total sample size of 2100. We report the results of dosimetric quality assurance, acute toxicity and pre planned first interim safety analysis in the first 271 patients.

METHODS

Stage I-III breast cancer planned for adjuvant radiation therapy to the breast/chest-wall (along with regional nodes as indicated) were randomised to receive 40 Gy/15 fractions/3 weeks or 26 Gy/5 fractions/1 week. For simultaneous integrated boost, the patients in the control arm received 8 Gy/15 fractions/3 weeks, while those in the experimental arm received 6 Gy/5 fractions/1 week (to the tumour bed). For sequential boost, the prescribed dose was 12 Gy/4 fractions/4 days in both arms. Compliance to pre specified dosimetric parameters and acute toxicities were evaluated.

RESULT

Data of the first 271 patients was analysed of whom 104 patients received tumour bed boost using SIB. All mandatory dosimetric criteria were met apart from one patient with a higher contralateral breast dose due to optimal internal mammary nodal coverage. Overall three patients (1.1%) experienced grade 3 radiation dermatitis (none received SIB), no other Grade 3 or higher toxicities reported.

CONCLUSION

This acute toxicity interim analysis demonstrates that hypofractionated adjuvant radiotherapy with SIB for patients with breast cancer is feasible, and associated with minimal severe acute toxicities.

Prone Breast and Lymph Node Irradiation in 5 or 15 Fractions: A Randomized 2 × 2 Design Comparing Dosimetry, Acute Toxicity, and Set-Up Errors

PURPOSE

Prone whole breast irradiation results in lower dose to organs at risk compared with supine position, especially lung dose. However, the adoption of prone position for whole breast irradiation + lymph node irradiation remains limited and data on lymph node irradiation in 5 fractions are lacking. Although the study was ended prematurely for the primary endpoint (breast retraction at 2 years), we decided to report acute toxicity for prone and supine positions and 5 and 15 fractions. Additionally, dosimetry and set-up accuracy between prone and supine positions were evaluated.

METHODS AND MATERIALS

A randomized open-label factorial 2 × 2 design was used for an acute toxicity comparison between prone and supine positions and 5 and 15 fractions. The primary endpoint of the trial was breast retraction 2 years after treatment. In total, 57 patients were evaluated. Dosimetry and set-up errors were compared between prone and supine positions. All patients were positioned on either our in -house developed prone crawl breast couch or a Posirest-2 (Civco).

RESULTS

No difference in acute toxicity between prone and supine positions was found, but 5 fractions did result in a lower risk of desquamation (15% vs 41%; P = .04). Prone positioning resulted in lower mean ipsilateral lung dose (2.89 vs 4.89 Gy; P < .001), mean thyroid dose (3.42 vs 6.61 Gy; P = .004), and mean contralateral breast dose (0.41 vs 0.54 Gy; P = .007). No significant difference in mean heart dose (0.90 vs 1.07 Gy; P = .22) was found. Set-up accuracy was similar between both positions.

CONCLUSIONS

Unfortunately, the primary endpoint of the trial was not met due to premature closure of the trial. Acceleration in 5 fractions resulted in a lower risk of desquamation. Prone positioning did not influence acute toxicity or set-up accuracy, but did result in lower ipsilateral mean lung dose, thyroid dose, and contralateral breast dose.

Tailored treatment strategies for cancer patients during COVID-19 pandemic

The global pandemic of respiratory disease caused by the novel human coronavirus (SARS-CoV-2) has caused indefinite global distress, uncertainty, and disturbance. This pandemic has had direct and indirect impacts for the healthcare systems across the world, but certain subgroups of patients have been particularly affected. Among these groups are patients with cancer, who as a result of their immunosuppressed status either from the disease itself or as a consequence of treatment, are at increased risk of severe COVID-19 infection and complications. The pandemic has also led to limited resources as medical services have been primarily directed to emergency care. In this context, physicians and healthcare providers have had to balance the importance of continuing treatment of cancer patients with the risk of virus infection. In this review, we outline the treatment strategies for cancer patients during this pandemic, focusing on tailored treatment in this challenging situation of varying risks and benefits.

From 25 Fractions to Five: How Hypofractionation has Revolutionised Adjuvant Breast Radiotherapy

There is a sound empirical basis for hypofractionation in radiotherapy for breast cancer. This article reviews the radiobiological implications of hypofractionation in breast cancer derived from a series of clinical trials that began when 50 Gy in 25 fractions over 5 weeks was commonplace. These trials led first to 40 Gy in 15 fractions over 3 weeks and, subsequently, to 26 Gy in five fractions over 1 week being adopted as standards of care for many patients prescribed whole- or partial-breast radiotherapy after primary surgery.

Implicaciones de la pandemia en la radioterapia para el cáncer de mama. Radioterapia hipofraccionada

La pandemia por el nuevo coronavirus (SARS-CoV-2) ha puesto a prueba los sistemas de salud de todo el mundo, de una forma tan apremiante que no se veía hace muchos años. Las implicaciones en la atención en salud no afectan únicamente a los pacientes con la COVID-19, sino que son transversales a todas las enfermedades. Específicamente en cáncer de mama, los esquemas de radioterapia hipofraccionada constituyen una alternativa válida y segura que ayuda a disminuir la exposición de las pacientes al nuevo virus, la congestión de las instituciones de salud y los costos propios de los tratamientos oncológicos especializados. En este artículo, se realizó una revisión de la literatura más relevante sobre los regímenes acortados de radioterapia en cáncer de mama: hipofraccionamiento e hipofraccionamiento extremo, y sobre su equivalencia con el fraccionamiento estándar. Al final, se destacan las recomendaciones de diferentes sociedades científicas y expertos internacionales, para considerar esquemas de radioterapia hipofraccionados, a propósito de la contingencia de salud mundial.

Implementation of External Beam Five-Fraction Adjuvant Breast Irradiation in a US Center

Five-fraction adjuvant whole breast radiation has been shown to be a safe and effective alternative to longer fractionation regimens. Given the lack of international consensus on patient selection for the protocol, we developed a consensus protocol to guide patient selection and facilitate safe and efficient five-fraction radiation in our radiation medicine department. In developing the directive, we surveyed departmental physicians about their choice of adjuvant breast regimen for various clinical scenarios. Patient travel burden was the factor most strongly impacting radiation oncologists’ decision-making when considering prescribing a five-fraction course of adjuvant breast radiation; the length of clinical trial follow-up data and acute and late normal tissue effects also impacted it, along with personal clinical experience and experience of dosimetry and physics personnel. Relative value unit (RVU) reimbursement and financial toxicity to the patient were reported to be less important in decision-making. Physicians were most comfortable using five-fraction radiation in women >50 years of age with low-risk cancer and for patients unable to attend for longer treatment courses. Eight months after implementation, the protocol accounts for 4.7% of breast irradiation delivered in our department.

Breast Cancer and Atrial Fibrillation

This study aims to establish the incidence of atrial fibrillation (AF) in breast cancer (BC) patients, focusing on staging and anti-cancer treatment. A meta-analysis was conducted to investigate the incidence of AF in BC patients and compare this incidence to other cancers. Furthermore, we evaluated the occurrence of AF as an adverse effect of biological therapies vs. non-biological therapies vs. biological therapies + non-biological therapies in BC. Finally, we compared the incidence of AF in early BC and metastatic BC. Thirty studies were included. Twenty-two studies focused on BC, encompassing 166,271 patients. In the BC group, 2.7% of patients developed AF, while in the "all cancer" group, 5.8% of patients developed AF. In addition, there was no difference between different types of therapies (p = 0.61) and between early and metastatic BC (p = 0.57). The type of anti-cancer therapy and the staging of BC does not influence AF's occurrence in this neoplastic disease.

Ultrahypofractionated breast radiotherapy during SARS-CoV-2 virus pandemic, beyond fast-forward trial: a local experience

Background:

During the SARS-CoV-2 virus pandemic, University Hospital Birmingham NHS Trust Oncology Department incorporated the ultrahypofractionated regime of 26Gy/5 fractions alongside the moderate hypofractionated regime of 40Gy/15 fractions as part of local adjuvant breast radiotherapy treatment (RT) for eligible patients. We conducted a local study to assess the real-life experience of patients undergoing ultrahypofractionated schedule to compare feasibility and toxicity to the fast-forward trial during the COVID − 19 pandemic.

Methods:

A single institution, retrospective, qualitative study. Patients included had early-stage breast cancer and received adjuvant radiotherapy between 23 March 2020 and 31 May 2020, a total of 211 patients. Inclusion was irrespective of any other neoadjuvant/adjuvant treatments. Data were collected retrospectively for treatment dose, boost dose and toxicity.

Results:

Of the total 211 patients, 85 were treated with 26Gy in 5# and 19 patients received a boost as per the fast-forward protocol. Of these 85 patients, 15·9% did not report any skin toxicity post-treatment. 63·5% of patients reported RTOG Grade 1, 15·9% had RTOG Grade 2, and 1·6% reported RTOG Grade 3 skin toxicity. 3·2% of the patients could not be contacted for follow-up. Of the 19 patients who received a breast boost, 10·53% reported no skin changes. 78·9% reported Grade 1 skin toxicity. Both Grades 2a and 2b skin toxicity were reported by 5·26% each. The patient demographics and tumour characteristics in our study cohort were comparable to those within the fast-forward trial. In terms of post-RT skin toxicity, fewer patients reported any toxicity in the UHB patient cohort versus those in the trial, and the number of Grade 2/3 toxicities reported was also low. A delay in toxicity reporting from 2 weeks for 40Gy/15 to 3 weeks for 26Gy/5 was observed.

Conclusion:

Our study concluded that offering ultrahypofractionation was convenient for patients; reducing the number of hospital visits during the SARS-CoV-2 virus pandemic appeared safe in terms of acute post-RT-related skin toxicity. The reduced hospital visits limited exposure of patients and staff to the SARS-CoV-2 virus while also ensuring efficient use of Radiotherapy Department resources. Local follow-up protocols have been amended to ensure review at 3 weeks for the 26Gy/5 schedule to acknowledge the delay in acute toxicity development. To date, there is only 5-year toxicity and relapse data available from the fast-forward trial; therefore, hypofractionation schedules should be offered to patients as long as they fulfil the criteria and understand the limitations of the study as well as accelerated peer review processes in the face of the pandemic.

Ultra-hypofractionated whole breast adjuvant radiotherapy in the real-world setting: single experience with 271 elderly/frail patients treated with 3D and IMRT technique

PURPOSE

The purpose of the study was to evaluate the toxicity, local control, overall and disease-free survival of elderly breast cancer (BC) patients treated with adjuvant once-weekly ultra-hypofractionated radiotherapy (RT) either with intensity-modulated RT (IMRT) or 3D conformal RT (3DCRT).

METHODS

From July 2011 to July 2018, BC patients receiving 5.7 Gy once a week for 5 weeks to the whole breast after breast-conserving surgery were considered for the study. Inclusion criteria were: T1-T3 invasive BC, no or limited axillary involvement, age ≥ 65 years or women with commuting difficulties or disabling diseases.

RESULTS

A total of 271 patients were included in the study. Median age was 76 (46-86) years. Most of BC were T1 (77%), while the remaining were T2 (22.2%) and T3 (0.4%). Axillary status was negative in 68.3% of the patients. The only severe acute toxicity (G3) at the end of RT was erythema (0.4%), registered in the 3DCRT group; no G3 edema or epitheliolysis was recorded. With 18 months of median follow-up, severe early-late toxicity (G3) was reported in terms of fibrosis and breast retraction, both with an incidence of 1.4%, mostly in the 3DCRT group. Oncological outcomes at a median follow-up of 2.9 years reported 249/271 (91.9%) patients alive and free from any event and 5 (1.8%) isolated locoregional recurrences. At 3 years, disease-free survival and overall survival were 94.9% and 97.8%, respectively. Breast volume > 500 cm³ was reported as predictive for moderate-severe (≥ G2) acute toxicity.

CONCLUSIONS

Weekly ultra-hypofractionated whole breast RT seems feasible and effective. Toxicity was mild, local control was acceptable, and overall survival was 97.8% at 3 years. Rates of severe toxicity were reduced with the IMRT technique.

Accelerated radiotherapy in patients over sixty years old after mastectomy: Acute and one-year physician-assessed toxicity and health-related quality of life

INTRODUCTION

Postmastectomy radiotherapy reduces the risk of locoregional recurrence in breast cancer patients. The first results on accelerated radiotherapy in five fractions after breast conserving surgery are promising. The data on postmastectomy radiotherapy in five or six fractions is limited. We now present the data on acute and one-year toxicity and health related quality of life (HRQoL) after postmastectomy radiotherapy in patients of sixty years or older.

METHODOLOGY

119 patients received five fractions of 5.7 Gy to the chest wall and five fractions of 5.4 Gy to the lymph nodes over ten to twelve days. Physician-assessed toxicity were scored using the Common Terminology Criteria for Adverse Events version 4.03 toxicity scoring system and the LENT-SOMA scale. Fatigue was measured by the Multidimensional Fatigue Inventory (MFI-206). HRQoL was assessed using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire the breast cancer specific module and the BREAST-Q questionnaire.

RESULTS

Fatigue and edema were the most frequently observed physician-assessed toxicities. One year after radiotherapy only 12.9% experienced a clinically important deterioration in chest wall symptoms and in 22.9% of the patients were improved. Future perspective at one year after radiotherapy was improved in 40.0% of the patients. Patient-reported fatigue showed the greatest improvement.

CONCLUSION

Accelerated radiotherapy should be considered to minimize the burden of breast cancer treatment, especially in older patients.

[Patient selection and early tolerance of whole breast irradiation according to the "Fast Forward" protocol: Preliminary results]

PURPOSE

Moderate hypofractionated radiotherapy has become routine practice for a selected population of patients treated for early-stage breast cancer. In April 2020, the Fast Forward (FF) study was published which introduced another extreme hypofractionated radiotherapy regimen in five sessions over a week. The aim of this work is to evaluate the population of first patients in whom this regimen was used in our department, as well as the results in terms of early toxicity.

MATERIAL AND METHODS

We retrospectively analysed all the patients treated in our department according to the Fast Forward protocol after establishing an institutional consensus regarding the selection of patients with breast cancer without indication for lymph node irradiation. All patients received breast-only irradiation at a total dose of 26Gy in five fractions according to protocol. All patients were treated by modern conformational techniques with planning large volume coverage between 95 and 100%. Acute toxicity of the treatment was assessed using the NCI CTC v4.0 scale and the general condition was assessed according to the WHO classification.

RESULTS

Between August 2020 and May 2021, 30 patients were included, treated on the breast alone without complement on the tumour bed or irradiation of the lymph node areas. The median age of the patients was 80years (range: 60-85years) with performance status 2 in 27 cases (89%). Only one patient had metastatic disease (3%), one patient presented locally advanced and 28 (94%) patients had early stage disease. Three patients (10%) were treated in dorsal decubitus according to the "field in the field" technique and 27 patients (90%) in isocentric lateral decubitus, which made it possible to avoid the organs at risk such as the heart (average dose of less than 1Gy) and the lungs. The early toxicity observed was grade I radio dermatitis in 8 patients (27%). No grade 2 and 3 toxicity, as well as radiation-induced pain or lymphedema were observed.

CONCLUSIONS

The results of this series of patients treated with hypofractionated radiotherapy according to the Fast Forward protocol on the breast alone with adapted techniques show that the protocol is feasible, with little early toxicity but a greater follow-up is necessary to assess long-term toxicity.

Five-fraction Radiotherapy for Breast Cancer: FAST-Forward to Implementation

INTRODUCTION

The phase 3 FAST-Forward trial reported outcomes for 26 and 27 Gy schedules delivered in 5 fractions over 1 week versus 40 Gy in 15 fractions over 3 weeks in 4000 patients. We discuss concerns raised by the radiotherapy community in relation to implementing this schedule.

IPSILATERAL BREAST TUMOUR RELAPSE (IBTR)

Published estimated 5-year IBTR with 95% CI after 40 Gy in 15 fractions was 2.1% (95% CI 1.4-3.1), 1.7% (1.2-1.6) after 27 Gy and 1.4% (0.2-2.2) after 26 Gy, emphatically showing non-inferiority of the 5-fraction regimens. Subgroup analyses comparing IBTR in 26 Gy versus 40 Gy show no evidence of differential effect regarding age, grade, pathological tumour size, nodal status, tumour bed boost, adjuvant chemotherapy, HER2 status and triple negative status. The number of events in these analyses is small and results should be interpreted with caution. There was only 1 IBTR event post-mastectomy.

NORMAL TISSUE EFFECTS

The 26 Gy schedule, on the basis of similar NTE to 40 Gy in 15 fractions, is the recommended regimen for clinical implementation. There is a low absolute rate of moderate/marked NTE, these are predominantly moderate not severe change. Subgroup analyses comparing clinician-assessed moderate or marked adverse effect for 26 Gy versus 40 Gy show no evidence of differential effects according to age, breast size, surgical deficit, tumour bed boost, or adjuvant chemotherapy.

RADIOBIOLOGICAL CONSIDERATIONS

The design of the FAST-Forward trial does not control for time-related effects, and the ability to interpret clinical outcomes in terms of underlying biology is limited. There could conceivably be a time-effect for tumour control. A slight reduction in α/β estimate for the late normal tissue effects of test regimens might be a chance effect, but if real could reflect fewer consequential late effects due to lower rates of moist desquamation.

CONCLUSION

The 26 Gy 5-fraction daily regimen for breast radiotherapy can be implemented now.

Modern radiation techniques in early stage breast cancer for the breast radiologist

Partial breast irradiation (PBI) and ultra-hypofractionated whole breast irradiation (uWBI) are contemporary alternatives to conventional and standard hypofractionated whole breast irradiation (WBI), which shorten treatment from 3 to 6 weeks to 1-2 weeks for select patients. PBI and accelerated PBI (APBI) can be delivered with external beam radiation (3D conformal radiation therapy (3D-CRT) or intensity modulated radiation therapy (IMRT)), intraoperative radiation (IORT), or brachytherapy. These new radiation techniques offer the advantage of convenience and lower cost, which ultimately improves access to care. Globally, the COVID 19 pandemic has accelerated APBI/PBI and ultra-hypofractionated regimens into routine practice for carefully selected patients. Recent long-term data from randomized controlled trials (RCTs) have demonstrated these techniques are safe and effective in suitable patients demonstrating equivalent or improved local recurrence, acute/late toxicity, and cosmesis. PBI and APBI should be limited to low risk unifocal invasive ductal carcinoma and ductal carcinoma in situ with tumor size < 2 cm, clear margins (≥2 mm), ER+, and negative nodes. Based on the results from UK Fast-Forward and UK FAST ultra-hypofractionated breast radiation can be safely employed for early stage node negative patients, but is not yet considered an international standard of care. In this review, authors will appraise recent data for these shorter course radiation treatment regimens, as well as, considerations for breast radiologists including surveillance imaging and radiographic findings.

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

•

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

•

The risk of recurrence of breast cancer is basically low.

•

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

•

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

•

Prospective randomized trial is warranted.

Purpose

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

Materials and methods

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

Results

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

Conclusion

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

Radiation Oncologists' Views on Breast Radiation Therapy Guidelines: Utilizing an Online Q&A Platform to Assess Current Views on Whole-Breast Irradiation Therapy

INTRODUCTION

Poor adherence to the 2011 American Society for Radiation Oncology (ASTRO) evidence-based guideline on whole-breast irradiation (WBI) has been reported. We utilized theMednet to assess the views of the updated 2018 guideline among radiation oncologists (ROs).

METHODS

We identified 11 questions asked by community ROs on theMednet, a web-based platform, between October 27, 2014 and May 2, 2017 that were updated in the 2018 guideline. New answers provided by senior authors of the 2018 guideline, cited guidelines, and polls to survey ROs were disseminated in 3 theMednet's newsletters between March 16, 2018 and May 1, 2018. Any question with less than 60% consensus was resubmitted on October 9, 2019 and assessed on February 13, 2020.

RESULTS

A total of 792 ROs responded to the initial surveys. In each survey, the answer choice(s) that received the majority of the votes aligned with the 2018 guideline. The strongest consensus was for the use of hypofractionated (HF)-WBI regardless of histology (97%), followed by HF-WBI boost dose (92%), molecular subtype (90%), grade (88%), and concurrent use of trastuzumab (87%). The least consensus was for age at which HF-WBI should be offered with 53% of respondents, specifically 73% of academic ROs versus 47% of community ROs (P = .001), agreeing with the guideline. The re-submitted survey 19 months later showed 77% of 287 new respondents now agreed with the guideline regarding age.

CONCLUSION

The majority of ROs concur with the 2018 WBI guideline in theMednet surveys, with better agreement among academic ROs than community ROs for certain components of the guideline. Further research into the different practice patterns may optimize patient care.

Dose constraints for whole breast radiation therapy based on the quality assessment of treatment plans in the randomised Danish breast cancer group (DBCG) HYPO trial

Purpose

Quality assessment of the treatment plans in the Danish Breast Cancer Group (DBCG) HYPO trial was carried out based on prospectively reported dosimetric parameters and evidence-based dose constraints for whole breast radiation therapy were derived.

Materials and methods

From 2009 to 2014, 1882 patients (pts) were randomised between 50 Gy/25fractions (fr) versus 40 Gy/15fr. Doses to CTVp_breast (V_95%, V_107%-V_110%, D_max, and in addition for 40 Gy plans V_105%-V_107%), ipsilateral lung (V_20Gy/V_17Gy), heart (V_20Gy/V_17Gy, V_40Gy/V_35Gy), and left anterior descending coronary artery (LADCA) (D_max) and use of respiratory gated technique were prospectively reported to the DBCG database. After end of accrual, these dosimetric parameters from all plans in the trial were compared to the pre-specified treatment constraints.

Results

In total, 1854 pts from eight radiation therapy (RT) centres in three countries were treated. No statistically significant differences were found between the results for 40 Gy and 50 Gy plans, except for CTVp_breast hot-spot volume (V_107%-V_110%). Of the 40 Gy pts, 90% with CTVp_breast > 600 mL and 95% with CTVp_breast ≤ 600 mL had a CTVp_breast hot-spot volume (V_105%-V_107%) <2%. In 95% of the 50 Gy plans, the CTVp_breast absolute hot-spot volume (V_107%-V_110%) was <0.5 mL and 1.7 mL for CTVp_breast ≤ 600 mL and > 600 mL, respectively. Compliance was >99% for both heart and lung constraints. Largest deviation from protocol constraints was found for the volume of CTVp_breast covered with 95% of the prescription dose or more (V_95%). The CTV dose coverage (V_95%) was >94.3% in 95% of the right-sided pts, whereas the figures for 95% of the left-sided pts treated with and without respiratory gating were 93.2% and 88.8%, respectively.

Conclusion

A high degree of compliance with protocol dose constraints was found for treatment plans in the DBCG HYPO trial. New constraints for dose to organs at risk and high-dose volumes in the breast are suggested for breast-only RT planning.

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

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

A Phase II Trial of Once Weekly Hypofractionated Breast Irradiation for Early Stage Breast Cancer

PURPOSE

To report an interim analysis of a phase II trial of once weekly, hypofractionated breast irradiation (WH-WBI) following breast conserving surgery (BCS).

METHODS

Patients had stage 0-II breast cancer treated with breast BCS with negative margins. WH-WBI was 28.5 or 30Gy delivered to the whole breast using tangential beams with no elective coverage of lymph nodes. The primary endpoint was ipsilateral breast tumor recurrence (IBTR). Secondary endpoints were distant disease-free survival (DDFS), recurrence free survival (RFS), overall survival (OS), adverse events and cosmesis.

RESULTS

From 2011 to 2015, 158 patients received WH-WBI. Median follow up was 4.4 years (range 0.2-8.1). Stage distribution was DCIS 22%; invasive pN0 68%; invasive pN1 10%. 80 patients received 30 Gy and 78 received 28.5 Gy with median follow up times of 5.6 and 3.7 years, respectively. There were 5 IBTR events, all in the 30 Gy group. The 5- and 7- year risks of IBRT for all patients were 2.2% (95% CI 0.6-5.8) and 6.0% (95% CI 1.1-17.2), respectively. The 7-year rates of DDFS, RFS, and OS were 96.3%, 91.5% and 89.8%, respectively. Improvement in IBTR-free time was seen in DCIS, lobular histology, low grade tumors, Her2 negative tumors and 28.5 Gy dose (all p < 0.0001).

CONCLUSIONS

Disease-specific outcomes after WH-WBI are favorable and parallel those seen with conventional radiation techniques for stage 0-II breast cancer.

Intrafraction motion monitoring to determine PTV margins in early stage breast cancer patients receiving neoadjuvant partial breast SABR

BACKGROUND AND PURPOSE

To quantify intra-fraction tumor motion using imageguidance and implanted fiducial markers to determine if a 5 mm planning-target-volume (PTV) margin is sufficient for early stage breast cancer patients receiving neoadjuvant stereotactic ablative radiotherapy (SABR).

MATERIALS AND METHODS

A HydroMark© (Mammotome) fiducial was implanted at the time of biopsy adjacent to the tumor. Sixty-one patients with 62 tumours were treated prone using a 5 mm PTV margin. Motion was quantified using two methods (separate patient groups): 1) difference in 3D fiducial position pre- and post-treatment cone-beam CTs (CBCTs) in 18 patients receiving 21 Gy/1fraction (fx); 2) acquiring 2D triggered-kVimages to quantify 3D intra-fraction motion using a 2D-to-3D estimation method for 44 tumours receiving 21 Gy/1fx (n = 22) or 30 Gy/3fx (n = 22). For 2), motion was quantified by calculating the magnitude of intra-fraction positional deviation from the pretreatment CBCT. PTV margins were derived using van Herkian analysis.

RESULTS

The average ± standard deviation magnitude of motion across patients was 1.3 ± 1.15 mm Left/Right (L/R), 1.0 ± 0.9 mm Inferiorly/Superiorly (I/S), and 1.8 ± 1.5 mm Anteriorly/Posteriorly (A/P). 85/105 (81%) treatment fractions had dominant anterior motion. 6/62patients (9.7%) had mean intra-fraction motion during any fraction > 5 mm in any direction, with 4 in the anterior direction. Estimated PTV margins for single and three-fx patients in the L/R, I/S, and A/P directions were 6.0x4.1x5.9 mm and 4.5x2.9x4.3 mm, respectively.

CONCLUSION

Our results suggest that a 5 mm PTV margin is sufficient for the I/S and A/P directions if a lateral kV image is acquired immediately before treatment. For the L/R direction, either further immobilization or a larger margin is required.

Cost Minimization Analysis of Hypofractionated Radiotherapy

Early-stage breast cancer patients comprise a large proportion of patients treated with radiotherapy in Canada. Proponents have suggested that five-fraction hypofractionated radiotherapy for these patients would result in significant cost savings. An assessment of this argument is thus warranted. The FAST-Forward and UK FAST clinical trials each demonstrated that their respective hypofractionated regimens provided equivalent outcomes compared with standard regimens. Thus, a cost-minimization analysis was performed to quantify the potential savings associated with these regimens, which were designated as FAST-Forward 1 (26 Gy/5 fractions/1 week) and FAST-Forward 2 (27 Gy/5 fractions/1 week), and UK FAST 1 (28.5 Gy/5 fractions/5 weeks) and UK FAST 2 (30 Gy/5 fractions/5 weeks). A standard regimen of 42.5 Gy/16 fractions/5 weeks was also included. A comprehensive model of radiotherapy costs for a Canadian cancer centre was created. Time, labour costs, and capital costs were calculated for each regimen and applied using established measures. The total costs per patient for the FAST-Forward trials were $851.77 for FAST-Forward 1 and $874.77 for FAST-Forward 2, providing a total savings of $487.99 and $464.99, respectively. Similarly, the total costs per patient for the FAST trials were $979.75 for UK FAST 1 and $1017.70 for UK FAST 2, providing savings of $360.01 and $322.06, respectively. Following the FAST-Forward 1 regimen results in the greatest reduction of infrastructure and human resources costs at 36.42% compared with the standard. Sensitivity analysis shows a maximum per-patient costs savings ranging from $474.60 to $508.53 for the FAST-Forward 1 trial, which translates to an annual savings of $174,700/year locally and $2.06 million/year province-wide, based on a moderate-to-large size department workload. Compared with a standard radiotherapy regimen, all FAST-Forward and UK FAST hypofractionated regimens provide cost savings for the treatment of early-stage breast cancer. The cost savings associated with each of these equivalent regimens can be directly calculated; activities in this model can easily be adjusted to account for cost variations, allowing other centres to calculate cost impacts specific to their own centres.

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.

The necessity of using deep inspiration breath-hold in the radiotherapy of left breast cancer patients who undergo the UK FAST trial

Aim : The purpose of the current study was to compare between deep inspiration breath-hold (DIBH) and free-breathing (FB) method in the setup reproducibility and to perform a dosimetric comparison between both methods in left-sided breast cancer patients who undergo the UK FAST trial. Materials and methods : The online matching correction data were retrospectively collected for 50 patients treated with the FAST trial. They were equally divided into DIBH and FB groups to compare between both methods in the setup reproducibility and create the appropriate planning target volume (PTV) margin. Ten patients out of the fifty were scanned in DIBH and FB to perform a dosimetric comparison with the strict acceptance criteria of the FAST trial. Results : All heart dosimetric parameters of the DIBH was significantly lower than that of FB (p < 0.001), and the lung V30% of DIBH plans was significantly lower than FB plans (p = 0.03). There was no statistically significant difference between the two methods in the other organs at risk doses. To fulfill the heart and lung constraints in FB plans, the PTV V90% was reduced by 3.4%, and three plans would not attain the PTV acceptance criteria. There was no significant difference between the systematic or random setup errors between both methods except the left-right random shift was significantly lower in DIBH cases (p = 0.004). The calculated PTV margins were (4 mm, 3 mm, and 4 mm) for DIBH group, and (5 mm, 6 mm, and 8 mm) for FB group in the anterior-posterior, superior-inferior, and left-right shifts, respectively. Conclusion : It is highly warranted to treat left-sided breast cancer patients with the DIBH technique when the UK FAST trial is employed for treatment.