The UK Standardisation of Breast Radiotherapy (START) Trial A of radiotherapy hypofractionation for treatment of early breast cancer: a randomised trial

Safety of hypofractionated volumetric modulated arc therapy for early breast cancer: A preliminary report

The present study attempts to evaluate the acute and subacute toxicities of hypofractionated volumetric modulated arc therapy (HFX-VMAT) in patients with early breast cancer (EBC). It is a retrospective analysis of 23 patients treated with HFX-VMAT after breast-conserving surgery between September 2021 and February 2022. A total dose of 50.05 to 52.55 Gy was delivered, consisting of 40.05 Gy to the ipsilateral whole breast in 15 fractions of 2.67 Gy and a tumor bed boost dose of 10-12.5 Gy in 4-5 fractions. The primary endpoint was acute/subacute radiation pneumonitis (RP). The secondary endpoint was poor cosmesis, indicating acute/subacute radiation dermatitis. Chest computed tomography (CT) and the Common Terminology Criteria for Adverse Events v.5.0 were used to assess acute and subacute RP and dermatitis, respectively, during radiotherapy (RT) and at 3- and 6-months post-RT. The median follow-up duration was 3.8 months (range, 2.3-4.2). A total of seven patients developed RP. None of these patients presented RP-related symptoms; the diagnosis was based on radiologic findings observed on follow-up chest CT. Among the seven patients with RP, five had right-sided, and two had left-sided breast tumors (71.4 vs. 28.6%; P=0.026). Grade 1 erythema was observed in 19 patients (82.6%) and grade 2 erythema in four (17.4%). The mean target dose, D_105% (the dose received by 105% of the target volume), homogeneity index, mean lung dose, ipsilateral lung V₂₀ (the percentage volume receiving 20 Gy), and V₃₀ (the percentage volume receiving 30 Gy) for ipsilateral whole breast RT were significantly associated with RP (P=0.039, 0.047, 0.018, 0.015, 0.018 and 0.003, respectively.). HFX-VMAT showed tolerable acute/subacute toxicities. Therefore, HFX-VMAT is an effective and safe treatment option for EBC.

Moderately hypofractionated post-operative radiation therapy for breast cancer: preferences amongst radiation oncologists from countries in Latin America and the Caribbean

Background

The safety and effectiveness of moderately hypofractionated post-operative radiation therapy for breast cancer were demonstrated by several trials. This study aimed to evaluate the current patterns of practice and prescription preference about moderately hypofractionated post-operative radiation therapy to assess possible aspects that affect the decision-making process regarding the use of fractionation in breast cancer patients in Latin America and the Caribbean (LAC). We also aimed to identify factors that can restrain the utilization of moderately hypofractionated post-operative radiation therapy for breast cancer.

Materials an methods

Radiation oncologists from LAC were invited to contribute to this study. A 38-question survey was used to evaluate their opinions.

Results

A total of 173 radiation oncologists from 13 countries answered the questionnaire. The majority of respondents (84.9%) preferred moderately hypofractionated post-operative radiation therapy as their first choice in cases of whole breast irradiation. Whole breast plus regional nodal irradiation, post-mastectomy (chest wall and regional nodal irradiation) without reconstruction, and post-mastectomy (chest wall and regional node irradiation) with reconstruction hypofractionated post-operative radiation therapy was preferred by 72.2% 71.1%, and 53.7% of respondents, respectively. Breast cancer stage, and flap-based breast reconstruction were the factors associated with absolute contraindications for the use of hypofractionated schedules.

Conclusion

Even though moderately hypofractionated post-operative radiation therapy for breast cancer is considered a new standard to the vast majority of the patients, its unrestricted application in clinical practice across LAC still faces reluctance.

Dosimetry and Toxicity Outcomes in Patients Treated with Hypofractionated Regional Nodal Irradiation for Breast Cancer: What is the Best Dose-Volume Limit to Minimize Risks of Radiation Pneumonitis?

PURPOSE

Although published data have supported the use of hypofractionated regional nodal irradiation (HF-RNI) for breast cancer, limited dosimetric data exist to evaluate predictors of lung toxicity. The ongoing RT CHARM trial limits the percentage of ipsilateral lung volume that receives ≥18 Gy to 35 to 40%. We assessed dosimetry, toxicity, and disease outcomes in patients with breast cancer treated with HF-RNI with a particular focus on pneumonitis.

METHODS AND MATERIALS

We retrospectively reviewed all patients with breast cancer treated with HF-RNI (40-43 Gy in 15-16 fractions) after either lumpectomy or mastectomy at The University of Pittsburgh Medical Center from September 2018 to December 2021 to collect dosimetric and outcomes data. All post-radiation therapy chest computed tomography (CT) scans were manually reviewed for evidence of acute (≤6 months postradiation) or chronic (>6 months postradiation) pneumonitis.

RESULTS

One-hundred-ninety-one patients qualified with a median follow-up of 20.3 months (range, 5.1-42.2). Acute grade 1 (G1) pneumonitis was observed in 6.8% of the overall cohort (13 of 191 patients) and 39.4% of the patients (13 of 33) who received a chest CT ≤6 months postradiation therapy. Only 1 patient developed acute G2 pneumonitis. Chronic G1 pneumonitis was observed in 29.8% of the overall cohort (57 of 191 patients) and 77% of patients (57 of 74 patients) who received a chest CT >6 months postradiation therapy. No patients developed acute G3+ or chronic G2+ pneumonitis.

CONCLUSIONS

Rates of symptomatic pneumonitis were low in this cohort of patients treated with HF-RNI, even with integration of HER2/neu-directed therapy, chemotherapy, hormone therapy, and internal mammary nodal irradiation. Lung V20Gy <26% appeared safe in this cohort to limit symptomatic pneumonitis, though this is not meant to represent the safe upper limit. Given the low event rate of symptomatic pneumonitis, data from larger cohorts will be needed to assess dosimetric predictors and the safe upper limit of lung dose.

Radiotherapy service amidst COVID-19: Experience from Tertiary Referral Hospital in Semarang, Indonesia

Background

Several changes in hospital policies took place to mitigate the spread of Coronavirus disease 2019 (COVID-19). However, the patient's perception to these abrupt changes in medical services is not known. This study analyzed the quality of radiotherapy service during the COVID-19 pandemic and the patient's perception of them.

Methods

This descriptive study will qualitatively assess cancer patient perception of the quality of radiotherapy service during COVID-19 pandemic. Willing participants were given a questionnaire that explore two major aspects: the patient's general knowledge of COVID-19 and their perception of radiotherapy service during the pandemic.

Results

The 145 participants of this study were generally well-informed about the significance of COVID-19 pandemic. Most respondents claimed to adequately practice preventive measures and put high regards in personal protective equipment (PPE) worn by them and healthcare workers for their safety. Their level of trust to all healthcare workers remained high and identified hospital announcements (television, brochures) educated them the most in regards to the relationship of COVID-19 and cancer.

Conclusion

The changes in hospital policies and radiation oncology service in our institution were well-received by the study population. Despite the majority of respondents were afraid and anxious of being infected of COVID-19 while undergoing treatment, only a minority of them contemplated to delay or completely stop going for treatment. By adhering to major guidelines and adjustments of local resources, the delivery of radiotherapy service can remain consistent during the pandemic.

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.

Dose-escalated simultaneous integrated boost radiotherapy in early breast cancer (IMPORT HIGH): a multicentre, phase 3, non-inferiority, open-label, randomised controlled trial

BACKGROUND

A tumour-bed boost delivered after whole-breast radiotherapy increases local cancer-control rates but requires more patient visits and can increase breast hardness. IMPORT HIGH tested simultaneous integrated boost against sequential boost with the aim of reducing treatment duration while maintaining excellent local control and similar or reduced toxicity.

METHODS

IMPORT HIGH is a phase 3, non-inferiority, open-label, randomised controlled trial that recruited women after breast-conserving surgery for pT1-3pN0-3aM0 invasive carcinoma from radiotherapy and referral centres in the UK. Patients were randomly allocated to receive one of three treatments in a 1:1:1 ratio, with computer-generated random permuted blocks used to stratify patients by centre. The control group received 40 Gy in 15 fractions to the whole breast and 16 Gy in 8 fractions sequential photon tumour-bed boost. Test group 1 received 36 Gy in 15 fractions to the whole breast, 40 Gy in 15 fractions to the partial breast, and 48 Gy in 15 fractions concomitant photon boost to the tumour-bed volume. Test group 2 received 36 Gy in 15 fractions to the whole breast, 40 Gy in 15 fractions to the partial breast, and 53 Gy in 15 fractions concomitant photon boost to the tumour-bed volume. The boost clinical target volume was the clip-defined tumour bed. Patients and clinicians were not masked to treatment allocation. The primary endpoint was ipsilateral breast tumour relapse (IBTR) analysed by intention to treat; assuming 5% 5-year incidence with the control group, non-inferiority was predefined as 3% or less absolute excess in the test groups (upper limit of two-sided 95% CI). Adverse events were assessed by clinicians, patients, and photographs. This trial is registered with the ISRCTN registry, ISRCTN47437448, and is closed to new participants.

FINDINGS

Between March 4, 2009, and Sept 16, 2015, 2617 patients were recruited. 871 individuals were assigned to the control group, 874 to test group 1, and 872 to test group 2. Median boost clinical target volume was 13 cm3 (IQR 7 to 22). At a median follow-up of 74 months there were 76 IBTR events (20 for the control group, 21 for test group 1, and 35 for test group 2). 5-year IBTR incidence was 1·9% (95% CI 1·2 to 3·1) for the control group, 2·0% (1·2 to 3·2) for test group 1, and 3·2% (2·2 to 4·7) for test group 2. The estimated absolute differences versus the control group were 0·1% (-0·8 to 1·7) for test group 1 and 1·4% (0·03 to 3·8) for test group 2. The upper confidence limit for test group 1 versus the control group indicated non-inferiority for 48 Gy. Cumulative 5-year incidence of clinician-reported moderate or marked breast induration was 11·5% for the control group, 10·6% for test group 1 (p=0·40 vs control group), and 15·5% for test group 2 (p=0·015 vs control group).

INTERPRETATION

In all groups 5-year IBTR incidence was lower than the 5% originally expected regardless of boost sequencing. Dose-escalation is not advantageous. 5-year moderate or marked adverse event rates were low using small boost volumes. Simultaneous integrated boost in IMPORT HIGH was safe and reduced patient visits.

FUNDING

Cancer Research UK.

Post-mastectomy radiotherapy for women with early breast cancer and one to three positive lymph nodes

BACKGROUND

Continual improvement in adjuvant therapies has resulted in a better prognosis for women diagnosed with breast cancer. A surrogate marker used to detect the spread of disease after treatment of breast cancer is local and regional recurrence. The risk of local and regional recurrence after mastectomy increases with the number of axillary lymph nodes affected by cancer. There is a consensus to use radiotherapy as an adjuvant treatment after mastectomy (postmastectomy radiotherapy (PMRT)) in women diagnosed with breast cancer and found to have disease in four or more positive axillary lymph nodes. Despite data showing almost double the risk of local and regional recurrence in women treated with mastectomy and found to have one to three positive lymph nodes, there is a lack of international consensus on the use of PMRT in this group.

OBJECTIVES

To assess the effects of PMRT in women diagnosed with early breast cancer and found to have one to three positive axillary lymph nodes.

SEARCH METHODS

We searched the Cochrane Breast Cancer Group's Specialised Register, CENTRAL, MEDLINE, Embase, the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) and ClinicalTrials.gov up to 24 September 2021.

SELECTION CRITERIA

We included randomised controlled trials (RCTs). The inclusion criteria included women diagnosed with breast cancer treated with simple or modified radical mastectomy and axillary surgery (sentinel lymph node biopsy (SLNB) alone or those undergoing axillary lymph node clearance with or without prior SLNB). We included only women receiving PMRT using X-rays (electron and photon radiation), and we defined the radiotherapy dose to reflect what is currently being recommended (i.e. 40 Gray (Gy) to 50 Gy in 15 to 25/28 fractions in 3 to 5 weeks. The included studies did not administer any boost to the tumour bed. In this review, we excluded studies using neoadjuvant chemotherapy as a supportive treatment before surgery.

DATA COLLECTION AND ANALYSIS

We used Covidence to screen records. We collected data on tumour characteristics, adjuvant treatments and the outcomes of local and regional recurrence, overall survival, disease-free survival, time to progression, short- and long-term adverse events and quality of life. We reported on time-to-event outcome measures using the hazard ratio (HR) and subdistribution HR. We used Cochrane's risk of bias tool (RoB 1), and we presented overall certainty of the evidence using the GRADE approach.

MAIN RESULTS

The RCTs included in this review were subgroup analyses of original RCTs conducted in the 1980s to assess the effectiveness of PMRT. Hence, the type and duration of adjuvant systemic treatments used in the studies included in this review were suboptimal compared to the current standard of care. The review involved three RCTs with a total of 829 women diagnosed with breast cancer and low-volume axillary disease. Amongst the included studies, only a single study pertained to the modern-day radiotherapy practice. The results from this one study showed a reduction of local and regional recurrence (HR 0.20, 95% confidence interval (CI) 0.13 to 0.33, 1 study, 522 women; low-certainty evidence) and improvement in overall survival with PMRT (HR 0.76, 95% CI 0.60 to 0.97, 1 study, 522 women; moderate-certainty evidence). One of the other studies using radiotherapy techniques that do not reflect modern-day practice reported on disease-free survival in women with low-volume axillary disease (subdistribution HR 0.63, 95% CI 0.41 to 0.96, 1 study, 173 women). None of the included studies reported on PMRT side effects or quality-of-life outcome measures.

AUTHORS' CONCLUSIONS

Based on one study, the use of PMRT in women diagnosed with breast cancer and low-volume axillary disease indicated a reduction in locoregional recurrence and an improvement in survival. There is a need for more research to be conducted using modern-day radiotherapy equipment and methods to support and supplement the review findings.

A phase II randomized clinical trial to assess toxicity and quality of life of breast cancer patients with hypofractionated versus conventional fractionation radiotherapy with regional nodal irradiation in the context of COVID-19 crisis

Purpose

This study, conducted during the COVID-19 crisis, primarily aimed to compare the acute toxicity between conventional fractionated radiation therapy (CF-RT) with hypofractionated radiation therapy (HF-RT) among patients who underwent breast-conserving surgery or mastectomy in whom breast or chest wall and regional nodal irradiation (RNI) were indicated. The secondary endpoints were both acute and subacute toxicity, cosmesis, quality of life, and lymphedema features.

Methods

In this open and non-inferiority randomized trial, patients (n = 86) were randomly allocated 2:1 in the CF-RT arm (n = 33; 50 Gy/25 fractions ± sequential boost [10 Gy/5 fractions]) versus the HF-RT arm (n = 53; 40 Gy/15 fractions ± concomitant boost [8 Gy/15 fractions]). Toxic effects and cosmesis evaluation used the Common Terminology Criteria for Adverse Events, version 4.03 (CTCAE) and the Harvard/National Surgical Adjuvant Breast and Bowel Project (NSABP)/Radiation Therapy Oncology Group (RTOG) scale. For the patient-reported quality of life (QoL), the European Organisation for Research and Treatment of Cancer quality of life questionnaire (EORTC QLQ-C30) and the breast cancer-specific supplementary questionnaire (QLQ-BR23) were used. Lymphedema was assessed by comparing volume differences between the affected and contralateral arms using the Casley-Smith formula.

Results

Grade 2 and grade 3 dermatitis were lower with HF-RT than with CF-RT (28% vs. 52%, and 0% vs. 6%, respectively; p = 0.022). HF-RT had a lower rate of grade 2 hyperpigmentation (23% vs. 55%; p = 0.005), compared to CF-RT. No other differences in overall rates of physician-assessed grade 2 or higher and grade 3 or higher acute toxicity between HF-RT and CF-RT were registered. There was no statistical difference between groups regarding cosmesis, lymphedema rate (13% vs. 12% HF-RT vs. CF-RT; p = 1.000), and functional and symptom scales, during both the irradiation period and after 6 months of the end of treatment. The results revealed that the subset of patients up to 65 years or older did not show a statistical difference between both arm fractionation schedules (p > 0.05) regarding skin rash, fibrosis, and lymphedema.

Conclusion

HF-RT was non-inferior to CF-RT, and moderate hypofractionation showed lower rates of acute toxicity, with no changes in quality-of-life outcomes.

Clinical trial registration

ClinicalTrials.gov, identifier NCT40155531.

Not Too Little, Not Too Much: Optimizing More Versus Less Locoregional Treatment for Older Patients With Breast Cancer

Although undertreatment of older women with aggressive breast cancers has been a concern for years, there is increasing recognition that some older women are overtreated, receiving therapies unlikely to improve survival or reduce morbidity. De-escalation of surgery may include breast-conserving surgery over mastectomy for appropriate candidates and omitting or reducing extent of axillary surgery. Appropriate patients to de-escalate surgery are those with early-stage breast cancer, favorable tumor characteristics, are clinically node-negative, and who may have other major health issues. De-escalation of radiation includes reducing treatment course length through hypofractionation and ultrahypofractionation regimens, reducing treatment volumes through partial breast irradiation, omission of radiation for select patients, and reducing radiation dose to normal tissues. Shared decision making, which aims to facilitate patients making decisions concordant with their values, can guide health care providers and patients through complicated decisions optimizing breast cancer care.

Clinical Outcomes of Patients with Metastatic Breast Cancer Treated with Hypo-Fractionated Liver Radiotherapy

PURPOSE

To retrospectively review the clinical outcomes of patients with metastatic breast cancer (MBCa) following liver directed ablative intent radiotherapy (RT).

METHODS

Demographics, disease and treatment characteristics of patients with MBCa who received liver metastasis (LM) directed ablative RT between 2004-2020 were analysed. The primary outcome was local control (LC), secondary outcomes included overall survival (OS) and progression-free survival (PFS) analyzed by univariate (UVA) and multi-variable analysis (MVA).

RESULTS

Thirty MBCa patients with 50 LM treated with 5-10 fraction RT were identified. Median follow-up was 14.6 (range 0.9-156.2) months. Class of metastatic disease was described as induced (12 patients, 40%), repeat (15 patients, 50%) and de novo (three patients, 10%). Median size of treated LM was 3.1 cm (range 1-8.8 cm) and median biologically effective dose delivered was 122 (Q1-Q3; 98-174) Gy₃. One-year LC rate was 100%. One year and two-year survival was 89% and 63%, respectively, with size of treated LM predictive of OS (HR 1.35, p = 0.023) on UVA. Patients with induced OMD had a significantly higher rate of progression (HR 4.77, p = 0.01) on UVA, trending to significance on MVA (HR 3.23, p = 0.051).

CONCLUSIONS

Hypo-fractionated ablative liver RT in patients with MBCa provides safe, tolerable treatment with excellent LC.

Delivery of a VMAT technique with flattening filter (FF) and flattening filter free (FFF) mode for whole breast irradiation with five fractions (FAST-Forward trial)

To investigate the feasibility of volumetric modulated arc therapy (VMAT) delivery for whole breast irradiation with a 5-fraction regimen according to the FAST-Forward trial. Recently, we treated 10 patients with carcinoma of the left breast after breast conserving surgery. The dose prescription to the PTV was 26 Gy in 5 fractions. Treatment plans were produced using a VMAT technique with the Eclipse treatment planning system for 6 MV flattening filter (FF) and FF free (FFF) beams. Dose volume histograms (DVHs) for the PTV and the organs at risk (OARs), the ipsilateral lung and heart, were compared with the dose constraints specified in the FAST-Forward trial (PTV, D95 > 95%, D5 < 105%, D2 < 107% and Dmax < 110%; ipsilateral lung, D15 < 8Gy; Heart, D30 < 1.5Gy and D5 < 7Gy). Furthermore, conformity index (CI), homogeneity index (HI) and dose to the heart, contralateral lung, contralateral breast, and left anterior descending artery (LAD), were also assessed. Mean ± SD D95(%), D5(%), D2(%), and Dmax (%) for PTV were 97.75 ± 1.12, 105.2 ± 0.82, 105.90 ± 0.89, 109.36 ± 1.00 (FF) and 96.46 ± 0.75, 103.97 ± 0.97, 104.70 ± 1.09, 108.58 ± 1.33 (FFF) respectively. The mean ± SD CI was 1.07 ± 0.05 (FF), 1.048 ± 0.06 (FFF) and HI was 0.11 ± 0.02 (FF), 0.10 ± 0.02 (FFF). Dose constraints for OARs were met for both treatment techniques. However, D15 (Gy) for ipsilateral lung was 3.0% lower with FFF beams. In contrast, D5 (Gy) for heart was 9.0% higher with FFF beams. The dose difference between FF and FFF beams for other OARs such as contralateral lung-D10 (Gy) contralateral breast-D5 (Gy) and LAD was up to 6.0%. Both FF and FFF methods met the acceptable criteria. However, the treatment plans with FFF mode were more conformal and provided greater target homogeneity.

Advancing Precision in Post-mastectomy Chest Wall Radiotherapy: A Comparative Dosimetric Analysis of Volumetric-Modulated Arc Therapy (VMAT) and Intensity-Modulated Radiotherapy (IMRT) Based on Institutional Experience

BACKGROUND

Post-mastectomy radiation therapy (PMRT) is an important component in the management of breast cancer patients who have undergone mastectomy. Intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) are two popular methods of delivering PMRT. With IMRT, high radiation doses are directed at the tumor, while exposure to healthy tissue is kept to a minimum. VMAT, on the other hand, is a more advanced version of IMRT that allows for faster radiation dose delivery while maintaining precision. The complexity of the VMAT treatment planning and delivery process, on the other hand, may increase the risk of technical errors, which can reduce treatment effectiveness.  Studies have compared VMAT and IMRT in PMRT for breast cancer patients, but most have found no significant differences in treatment outcomes between the two methods. Individual patient factors such as treatment goals, available resources, and other characteristics may influence the choice between the two techniques.

PURPOSE

 This prospective observational study aimed to compare the dosimetry of two cutting-edge modern radiotherapy techniques for post-mastectomy breast cancer patients receiving hypofractionated doses.

METHODS

 For 58 patients with breast cancer, 116 plans for radiotherapy treatment were generated by both VMAT and IMRT. To maintain the uniformity of contouring, every CT image was contoured by the same physician, and Radiotherapy Oncology Group (RTOG) contouring guidelines were strictly followed during contouring.

RESULTS

Both techniques had comparable target volume coverage, but VMAT produced a significantly better conformity index than IMRT for both the left (0.71 vs. 0.65) and right (0.72 vs. 0.66) breasts (p-value < 0.05). VMAT plans had significantly higher low-dose spillage to the ipsilateral lung (V5Gy and V10Gy) but significantly lower high-dose spillage (V20Gy, V30Gy, and V40Gy) than IMRT plans (p-value < 0.05). Dmax and Dmean for the ipsilateral lung were comparable for both techniques. When compared to alternative treatment approaches, IMRT treatment plans were found to be more effective in minimizing radiation exposure to the heart for all patients with right-sided breast cancer, resulting in considerably lower levels of Dmean, V5Gy, V10Gy, V20Gy, and V35Gy. Plans for VMAT treatment were found to be significantly superior to left-side chest wall radiotherapy in terms of lower exposure to the heart for higher doses. IMRT plans, on the other hand, were successful in dramatically lowering the levels of Dmax that reached the spinal cord for both right- and left-sided breast cancers.

CONCLUSION

Apart from similar planning target volume (PTV) coverage to IMRT plans, VMAT produced significantly better conformity. VMAT plans have more low-dose spillage to normal tissues, while IMRT plans spare various organs at risk significantly better at lower doses in both right and left-sided breast cancer. VMAT was found to be better at sparing the heart (in left-sided breast cancer only) and ipsilateral lung at a high dose range. The best radiotherapy approach for breast cancer should be established on an individual basis, taking into account tumor laterality and the risk-benefit ratio.

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.

Dosimetric Comparison of Hypofractionated Regimen in Breast Cancer Using Two Different Techniques: Intensity-Modulated Radiation Therapy (IMRT) and Volumetric-Modulated Arc Therapy (VMAT)

INTRODUCTION

Breast cancer treated with adjuvant hypofractionation radiotherapy with two different techniques, i.e., volumetric-modulated arc therapy (VMAT) and intensity-modulated radiation therapy (IMRT) and their effects in terms of loco-regional control and adverse effects in terms of cutaneous, pulmonary, and cardiac outcomes are compared.

MATERIALS AND METHODS

This is a prospective non-randomized observational study. VMAT and IMRT plan for 30 breast cancer patients who were supposed to receive adjuvant radiotherapy were prepared using a hypofractionation schedule. The plans were dosimetrically evaluated.

OBJECTIVE

Dosimetric comparative analysis of IMRT and VMAT in hypofractionated radiotherapy in breast cancer is done and tested whether VMAT has a dosimetric advantage over IMRT. These patients were recruited for a clinical assessment of toxicities. They were followed up for at least three months.

RESULT

On dosimetric analysis, planning target volume (PTV) coverage (PTV_ V95) of both VMAT (96.41 ± 1.31) and IMRT (96.63 ± 1.56) were similar with significantly lower monitor units required with VMAT plans (1,084.36 ± 270.82 vs 1,181.55 ± 244.50, p = 0.043). Clinically, all patients tolerated hypofractionation through VMAT (n = 8) and IMRT (n = 8) satisfactorily in the short term. No cardiotoxicity or appreciable falls in pulmonary function test parameters were observed. Acute radiation dermatitis poses challenges similar to standard fractionation or any other delivery technique.

CONCLUSION

PVT dose, homogeneity, and conformity indices were similar in both VMAT and IMRT groups. In VMAT, there was high-dose sparing of some critical organs like the heart and lungs at the cost of the low-dose baths to these organs. Increased risk of secondary cancer will require a decade-long follow-up study to indict the VMAT technique. As we move toward precision in oncology, "one-size-fits-all" can never be an acceptable dictum. Each patient is unique and therefore we must offer, and the patient must "choose wisely."

Overall Survival and Related Factors of Patients Undergoing Breast-Conserving Surgery with Boost Through Interstitial Brachytherapy in a Cancer Center in Medellin, Colombia

Liza María González-HernándezPatients with breast cancer undergoing conservative surgery require management with radiotherapy to decrease the risk of recurrence. Moreover, the use of tumor bed boost in high-risk patients has shown an absolute reduction in the 10-year local recurrence risk from 23.9 to 13.5%. Therefore, this study aimed to estimate the overall survival of a group of patients undergoing conservative surgery with a boost through interstitial brachytherapy at a cancer center in Medellin, Colombia. A retrospective cohort study was performed, and records from 2014 to 2020 of patients with in situ or infiltrating breast cancer treated with a boost through interstitial brachytherapy were included. Univariate analysis was conducted to characterize the study population; median survival was calculated using the Kaplan-Meier method. Moreover, associations concerning survival were calculated with each of the factors independently. A total of 186 patients were included. Their overall survival was 93.5%, with a median survival of 79 months. The presence of negative hormone receptors, having two or more irradiated fields and having a locally advanced stage were factors associated independently with higher mortality. The overall survival of patients with in situ or infiltrating breast cancer was favorable and correlated with studies regarding intervention with a boost through interstitial brachytherapy and the factors associated with higher mortality, such as having a locally advanced stage.

Update on Accelerated Whole Breast Irradiation

Since the advent of breast conservation, adjuvant radiation therapy (RT) has been standard of care following breast conserving surgery (BCS). Radiation therapy following BCS has traditionally been whole breast irradiation (WBI); studies comparing breast conservation to mastectomy utilized standard fractionation WBI, which delivers treatment daily over 5 to 7 weeks (1.8-2 Gy/fraction) and was the standard for decades. More recently, multiple randomized trials have compared standard fractionation WBI to moderately hypofractionated WBI (2.66 Gy/fraction, 15-16 fractions), which allows for completion of treatment in 3 to 4 weeks. Results have demonstrated no difference in local control between these two approaches with comparable toxicity and cosmetic outcomes with long-term follow-up. As such, moderately hypofractionated WBI represents the standard of care approach for most patients with early-stage breast cancer following BCS at this time. In the past few years, ultra-hypofractionated WBI (5.2-5.7 Gy/fraction, 5 fractions) has emerged with promising outcomes; 5-year outcomes from the FAST-Forward randomized trial demonstrated noninferiority between ultra-hypofractionated WBI and moderately hypofractionated WBI. Moving forward, long-term outcomes from ultra-hypofractionated WBI studies are expected, as well as the potential for incorporating moderately hypofractionated regimens into patients requiring regional nodal irradiation following BCS. Finally, the advent of ultra-short regimens may allow clinicians to re-evaluate treatment de-intensification in early-stage breast cancer to consider radiation therapy alone following BCS in lieu of endocrine therapy.

Long-term outcomes and effects of hypofractionated radiotherapy in microinvasive breast cancer: Analysis from a randomized trial

PURPOSE

The natural history of microinvasive (T1mi) breast cancer is uncertain. The objective was to evaluate long-term local and distant recurrence rates following breast conserving surgery (BCS) in a prospective cohort of patients with T1mi compared to T1a-2 disease who received whole breast irradiation (WBI) in the context of a randomized trial of hypofractionation.

METHODS

1234 patients with T1-2 N0 breast cancer were randomized to receive adjuvant WBI of 42.5Gy in 16 daily fractions, or 50Gy in 25 daily fractions after BCS. An analysis of patients with T1mi tumors compared with T1a-2 disease was performed. Kaplan-Meier estimates of local recurrence (LR), distant recurrence, and overall survival (OS) were compared using the log-rank test.

RESULTS

Median follow-up was 12 years. T1mi was found in 3% (n = 38) of patients. The 10-year LR rate was 22.6% in T1mi vs. 6.9% in T1a-2 breast cancer [hazard ratio (HR) = 3.73; 95% confidence interval (CI): 1.93, 7.19; p < 0.001]. The 10-year risk of distant recurrence was 5.1% for T1mi, and 12.1% for T1a-2 disease (HR = 0.56; 95% CI: 0.19, 1.84; p = 0.36). Ten-year OS was 91.5% in T1mi and 84.4% in T1a-2 disease, (HR = 0.48; 95% CI: 0.18, 1.30; p = 0.14). Rates of LR did not differ whether treated by hypofractionation or conventional fractionation (HR = 1.21; 95% CI: 0.35, 4.18; p = 0.77).

CONCLUSIONS

The risk of LR was considerably higher in patients with T1mi compared to T1a-2 tumors, but OS remained very good. Future research should evaluate the utility of wider local excision and boost radiation to optimize local control for microinvasive breast cancer.

A Hypofractionated Radiotherapy Schedule with a Simultaneous Integrated Boost for Breast Cancer: Outcomes including Late Toxicity and Health Quality

Introduction: This study aimed to evaluate the long-term adverse effects on the physical appearance and overall well-being of breast cancer patients who receive hypofractionated radiotherapy as whole breast and simultaneous integrated boost (SIB) treatment, utilizing intensive modulated radiotherapy (IMRT), volumetric modulated arc therapy (VMAT), or a hybrid therapy approach. Material/Methods: This investigation involved administering hypofractionated SIB-VMAT therapy to individuals diagnosed with early-stage breast cancer. Treatment was carried out over a three-week period in which a total dose of 48.06 Gy was given to the entire breast and 54 Gy was given to the tumor bed. Data on skin toxicity and cosmetic outcomes were analyzed both during the acute phase and during the three-month and five-year follow-up periods after treatment. Results: A total of 125 patients treated between December 2014 and December 2016 were included in the study. The data of these patients with at least 5 years of follow-up were analyzed. Conclusions: Considering these long-term results, hypofractionated SIB-VMAT can be considered a viable treatment choice, even for patients with unfavorable conditions.

A retrospective study of adjuvant proton radiotherapy for breast cancer after lumpectomy: a comparison of conventional-dose and hypofractionated dose

Purpose

This study aimed to compare the adverse reactions of conventional-dose and hypofractionated dose of proton therapy for breast cancer.

Materials and methods

Breast cancer patients treated with proton radiotherapy in conventional-dose or hypofractionated dose were studied retrospectively.

Result

From January 2017 to December 2019, our center treated 50 patients following lumpectomy with proton radiotherapy. According to the AJCC 8th Edition standard, there were stage I in 26 patients, stage II in 22 patients, and stage III in 2 patients. A total of 14 patients received intensity-modulated proton therapy at a dose of 50 Gy in 25 fractions, followed by a 10 Gy 4 fractionated boost to the lumpectomy cavity, while 36 received 40.05 Gy in 15 fractions, simultaneous integrated boost (SIB) 48 Gy to the lumpectomy cavity. Median follow-up time for 40.05 Gy group was 35.6 months (15–43 months). Median follow-up time for 50 Gy group was 46.8 months (36–68 months). For acute toxicity, the grade 1 and 2 radiodermatitis in conventional-dose group were 35.7% and 57.1%, respectively. In hypofractionated dose group, the grade 1 and 2 radiodermatitis were 91.7% and 8.3%, respectively. The radiodermatitis is hypofractionneted dose better than conventional-dose significantly. Grade 1 radiation-induced esophagitis in conventional-dose group and hypofractionated dose group were 85.71% and 60%, respectively. For late toxicity, no patients developed radiation-induced pneumonitis and rib fracture in conventional-dose group. Three patients presented grade 1 pneumonitis; one patient presented graded 2 pneumonitides and two patients presented rib fracture in hypofractionated dose group. One presented hypothyroidism in hypofractionated dose group. All patients were satisfied with breast shape. The one- and two-year OS and DFS for conventional-dose group were 100 and 100; 100 and 92.9%, respectively. The one- and two-year OS and DFS for hypofractionated dose group were 100 and 100; 100 and 100%, respectively.

Conclusion

Proton radiation therapy can significantly reduce the normal tissue dose in breast cancer patients' hearts, lungs, and other organs. Hypofractionated proton therapy shortens the treatment course with mild radiation-related adverse effects, and has a better effect on addressing the acute adverse reactions than conventional proton radiotherapy.

Hypofractionated whole breast irradiation in association with hypofractionated or normofractionated boost to the tumor bed in early breast cancer: tolerance and efficacy analysis

BACKGROUND

The boost to the tumor bed improves local control in breast cancer and it is an important part of the breast conserving therapy. However, information about the use of a hypofractionated boost is sparse, thus further studies are needed. We conducted a retrospective study with the aim of comparing hypofractionated boost (HB) and normofractionated boost (NB) on skin toxicity and local control.

MATERIALS AND METHODS

A total of 96 women with early breast cancer undergoing breast-conserving surgery and hypofractionated whole breast irradiation (WBI) were retrospectively analyzed divided into hypofractionated boost group and conventional fractionation boost group. Forty-nine patients were treated with NB with 16 Gy in 8 fractions and 47 patients were treated with HB with 13.35 Gy in 5 fractions. We examined acute and chronic toxicity with CTCAE version 5.

RESULTS

The median follow-up was 49.5 months (26-67). Median age was 57 years (36-82). Sixty-six patients (68.7%) were younger than 60 years at the time of boost and 30 (31.2%) were older than 60 years who received the boost due to poor prognostic factors. No differences were found between the two groups in terms of patient, tumor or treatment characteristics. Grade 2 acute skin toxicity was 6.3% in the NB group and 4.2% in the HB group. Chronic skin induration was 4.2% in the NB group and 1% in the HB group. They did not show grade 3 skin toxicity. There were also no differences in acute or late skin toxicity between the two groups. No local recurrences were evidenced.

CONCLUSIONS

Hypofractionated WBI associated with HB treatment is a viable option in the management of conservative breast therapy given the good tolerance and similar local control.

Driving quality improvement through better data: The story of New Zealand's radiation oncology collection

Aotearoa/New Zealand is one of the first nations in the world to develop a comprehensive, high-quality collection of radiation therapy data (the Radiation Oncology Collection, ROC) that is able to report on treatment delivery by health region, patient demographics and service provider. This has been guided by radiation therapy leaders, who have been instrumental in overseeing the establishment of clear and robust data definitions, a centralised database and outputs delivered via an online tool. In this paper, we detail the development of the ROC, provide examples of variation in practice identified from the ROC and how these changed over time, then consider the ramifications of the ROC in the wider context of cancer care quality improvement. In addition to a review of relevant literature, primary data were sourced from the ROC on radiation therapy provided nationally in New Zealand between 2017 and 2020. The total intervention rate, number of fractions and doses are reported for select cancers by way of examples of national variation in practice. Results from the ROC have highlighted areas of treatment variation and have prompted increased uptake of hypofractionation for curative prostate and breast cancer treatment and for palliation of bone metastases. Future development of the ROC will increase its use for quality improvement and ultimately link to a real time cancer services database.

Association between Immediate Breast Reconstruction and the Development of Breast Cancer-Related Lymphedema

BACKGROUND

With the increasing number of patients undergoing immediate breast reconstruction after mastectomy, the impact of immediate breast reconstruction on the risk of breast cancer-related lymphedema has become an emerging area of interest. This study aimed to identify the association between immediate breast reconstruction and postoperative lymphedema.

METHODS

A retrospective cohort study was conducted from 2006 to 2016 with 5900 consecutive patients who underwent mastectomy for primary breast cancer with or without immediate breast reconstruction. After excluding patients with synchronous contralateral breast cancer, lymphedema before mastectomy, history of procedures performed in the axillary region, and follow-up data of less than 1 year, the cumulative incidence of lymphedema after immediate breast reconstruction and after no reconstruction was calculated and compared using multivariate Cox regression analysis.

RESULTS

Overall, 5497 patients (mean age, 51.7 years) were included, and 630 developed lymphedema. The 5-year cumulative incidence rate of lymphedema was significantly reduced in patients who underwent immediate breast reconstruction versus control patients (9.6% versus 12.2%; P = 0.02). In the multivariate analysis, immediate breast reconstruction status (hazard ratio, 0.75; 95% confidence interval, 0.56 to 0.99; P = 0.042) was an independent predictor for lymphedema. Similar significant associations were observed in the subgroup analyses of patients with a body mass index less than 30 kg/m2 (P = 0.024), in those with fewer than 10 dissected lymph nodes (P = 0.042), or in those with adjuvant radiotherapy (P = 0.048).

CONCLUSIONS

Immediate breast reconstruction was associated with a reduced risk of lymphedema. These results may be used for predicting the development of lymphedema following breast reconstruction.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, II.

A Precise Approach for Radiotherapy of Breast Cancer

Radiotherapy is an integral part of the multidisciplinary management of breast cancer (BC). There have been multiple recent advances in the delivery of radiotherapy, reviewed with a critical discussion of the evidence from trials investigating adjuvant ultra-hypofractionation and partial breast irradiation for early-stage BC, and the locoregional management of lymph nodes in locally advanced BC. Multiple precision medicine-based approaches have been developed as prognostic and/or predictive for BC patients and identifying biomarkers of radioresistance could help identify patients that may benefit from dose-escalated radiotherapy or radiosensitizers. Radiotherapy after breast reconstruction is an area of current controversy in the field, and we evaluated the decision-making considerations in this situation. The oligometastatic state is an emerging field for many cancer sites based on recent trials investigating ablative radiotherapy for oligometastatic BC. This chapter is an overview of radiotherapy for BC, with a focus on recent advances in early-stage, locally advanced, and oligometastatic disease.

Hypofractionation in Breast Cancer Radiotherapy Across World Bank Income Groups: Results of an International Survey

PURPOSE

Hypofractionated breast radiotherapy has been found to be equivalent to conventional fractionation in many clinical trials. Using data from the European Society for Radiotherapy and Oncology Global Impact of Radiotherapy in Oncology survey, we identified preferences for hypofractionation in breast cancer across World Bank income groups and the perceived facilitators and barriers to its use.

MATERIALS AND METHODS

An international, electronic survey was administered to radiation oncologists from 2018 to 2019. Demographics, practice characteristics, preferred hypofractionation regimen for specific breast cancer scenarios, and facilitators and barriers to hypofractionation were reported and stratified by World Bank income groups. Variables associated with hypofractionation were assessed using multivariate logistic regression models.

RESULTS

One thousand four hundred thirty-four physicians responded: 890 (62%) from high-income countries (HICs), 361 (25%) from upper-middle-income countries (UMICs), 183 (13%) from low- and lower-middle-income countries (LLMICs). Hypofractionation was preferred most frequently in node-negative disease after breast-conserving surgery, with the strongest preference reported in HICs (78% from HICs, 54% from UMICs, and 51% from LLMICs, P < .001). Hypofractionation for node-positive disease postmastectomy was more frequently preferred in LLMICs (28% from HICs, 15% from UMICs, and 35% from LLMICs, P < .001). Curative doses of 2.1 to < 2.5 Gy in 15-16 fractions were most frequently reported, with limited preference for ultra-hypofractionation, but significant variability in palliative dosing. In adjusted analyses, UMICs were significantly less likely than LLMICs to prefer hypofractionation across all curative clinical scenarios, whereas respondents with > 1 million population catchments and with intensity-modulated radiotherapy were more likely to prefer hypofractionation. The most frequently cited facilitators and barriers were published evidence and fear of late toxicity, respectively.

CONCLUSION

Preference for hypofractionation varied for curative indications, with greater acceptance in earlier-stage disease in HICs and in later-stage disease in LLMICs. Targeted educational interventions and greater inclusivity in radiation oncology clinical trials may support greater uptake.

A prospective randomized comparative study to evaluate the effect of palliative hypo-fractionated radiotherapy with concurrent chemotherapy versus hypo-fractionated radiotherapy alone in advanced and unresectable head and neck cancer with no metastasis

Introduction

A short duration, palliative radiotherapy schedule for locally advanced and unresectable head and neck cancer (LAUHNC) was evaluated in terms of palliation of cancer-related symptoms and acute toxicities.

Aims and objectives

The aim of the study was to compare the role and feasibility of hypo-fractionated radiotherapy with concurrent chemotherapy and hypo-fractionated radiotherapy in LAUHNC.

Materials and methods

All the patients included in this study of LAUHNC were not fit for curative treatment. These patients are assessed on the basis of quality of life (QOL), tumour response, toxicities, and relief in symptoms. QOL was assessed on the basis of University of Washington QOL questionnaire version 4 before and after treatment. Patients are divided into two arms, Arm A patients received 40 Gy in ten fractions concurrent cisplatin 50 mg/m2 with weekly and Arm B patients received 40 Gy in ten fractions. To assess the tumour response response evaluation criteria in solid tumours criteria were used.

Results

A total of 40 patients were enrolled in this study, with 20 patents in both arms. Three patients defaulted during treatment and one patient died during treatment. A total of 36 patients completed treatment. Before treatment common complaints was distressing pain in primary site, and difficulty in chewing and swallowing. After treatment there was reduction of pain and improvement in swallowing in both arms. Overall QOL improvement in Arm A (28.89 ± 18.44 to 46.67 ± 15.34) and in Arm B (31.11 ± 15.68 to 43.33 ± 15.72). Neither of the arms experienced grade IV mucositis and skin reaction.

Conclusion

Toxicity in the form of mucositis and dermatitis was higher in the concurrent hypo-fractioned arm compared to the only hypo-fractionated radiotherapy arm during the treatment and in follow up period. The QOL in both individual arms showed statistically significant results, however when the QOL of both the arms was compared, the results were not statistically significant.

Hypofractionated radiotherapy in postmastectomy locally advanced breast cancer: an interim report on acute toxicities and dosimetry

Background

There is a growing interest in the use of hypofractionation in the setting of post-mastectomy radiation therapy (PMRT). Here, we present an interim report on the acute toxicities and the dosimetry of a 15-day hypofractionated regimen.

Materials and methods

Patients aged 18-75 years who underwent mastectomy and had pathological stage IIB-IIIC or any clinical stage who had received neoadjuvant chemotherapy were treated with PMRT at a dose of 43.5 Gy in 15 fractions. Acute toxicities were scored using Common Terminology Criteria for Adverse Events (CTCAE) version 4.0.

Results

Between September 2020 and September 2021, 92 patients were enrolled in the study. Majority experienced grade 1 dermatitis during the course of treatment. Skin toxicities peaked two weeks after PMRT in which 57 patients (62%) had grade 2 dermatitis and 6 patients (7%) had grade 3 dermatitis. Most resolved one month after treatment, with all resolving at three months. Grade 2 fatigue occurred in 4 patients (4%). There were no grade 3 fatigue or pneumonitis of any grade. The average V95% for the chest wall, axilla, and supraclavicular fossa were 91.5%, 99.3%, and 97.5%, respectively. Average ipsilateral lung V17 was 43.6%, while the mean heart dose averaged at 3.46 Gy.

Conclusion

This interim report showed that hypofractionated PMRT is associated with a low incidence of clinically significant acute toxicities. With the use of the 3-dimensional conformal radiotherapy technique and volume-based planning, adequate target volume coverage and acceptable heart doses were achieved, although with a slightly higher ipsilateral lung dose.

Optimizing Adjuvant Treatment Recommendations for Older Women with Biologically Favorable Breast Cancer: Short-Course Radiation or Long-Course Endocrine Therapy?

Omission of radiotherapy among older women taking 5 years of adjuvant endocrine therapy following breast conserving surgery for early-stage, hormone sensitive breast cancers is well-studied. However, endocrine therapy toxicities are significant, and many women have difficulty tolerating endocrine therapy, particularly elderly patients with comorbidities. Omission of endocrine therapy among women receiving adjuvant radiation is less well-studied, but available randomized and non-randomized data suggest that this approach may confer equivalent local control and survival for select patients. Herein we review available randomized and non-randomized outcome data for women treated with radiation monotherapy and emphasize the need for future prospective, randomized studies of endocrine therapy omission.

Functional imaging-guided carbon ion irradiation with simultaneous integrated boost for localized prostate cancer: study protocol for a phase II randomized controlled clinical trial

Background

Due to the physical dose distribution characteristic of “Bragg peak” and the biological effect as a kind of high linear energy transfer ray, heavy ion therapy has advantages over conventional photon therapy in both efficacy and safety. Based on the evidence that prostate cancer lesions before treatment are the most common sites of tumor residual or recurrence after treatment, simultaneous integrated boost radiation therapy for prostate cancer has been proven to have the advantage of improving efficacy without increasing toxicities.

Methods

This study is a prospective phase II randomized controlled clinical trial evaluating the efficacy and safety of functional imaging-guided carbon ion irradiation with simultaneous integrated boost for localized prostate cancer. One hundred and forty patients with localized prostate cancer will be randomized into carbon ion radiotherapy group and simultaneous integrated boost carbon ion radiotherapy group at a 1:1 ratio. The primary endpoint is to compare the incidence of treatment-related grade 2 and higher acute toxicities between the two groups according to National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE) version 4.03. Secondary endpoints are late toxicities, biochemical relapse-free survival, overall survival, progression-free survival, and quality of life.

Discussion

This study adopts functional imaging-guided simultaneous integrated boost of carbon ion radiotherapy for localized prostate cancer, aiming to evaluate the differences in the severity and incidence of acute toxicities in patients with localized prostate cancer treated with carbon ion radiotherapy and simultaneous integrated boost carbon ion radiotherapy, in order to optimize the carbon ion treatment strategy for localized prostate cancer.

Trial registration

ClinicalTrials.gov NCT05010343. Retrospectively registered on 18 August 2021

Effectiveness of hypofractionated and normofractionated radiotherapy in a triple‐negative breast cancer model

Breast cancer (BC) is one of the most diagnosed malignant carcinomas in women with a triple-negative breast cancer (TNBC) phenotype being correlated with poorer prognosis. Fractionated radiotherapy (RT) is a central component of breast cancer management, especially after breast conserving surgery and is increasingly important for TNBC subtype prognosis. In recent years, moderately hypofractionated radiation schedules are established as a standard of care, but many professionals remain skeptical and are concerned about their efficiency and side effects. In the present study, two different triple-negative breast cancer cell lines, a non-malignant breast epithelial cell line and fibroblasts, were irradiated daily under normofractionated and hypofractionated schedules to evaluate the impact of different irradiation regimens on radiation-induced cell-biological effects. During the series of radiotherapy, proliferation, growth rate, double-strand DNA break-repair (DDR), cellular senescence, and cell survival were measured. Investigated normal and cancer cells differed in their responses and receptivity to different irradiation regimens, indicating cell line/cell type specificity of the effect. At the end of both therapy concepts, normal and malignant cells reach almost the same endpoint of cell count and proliferation inhibition, confirming the clinical observations in the follow-up at the cellular level. These result in cell lines closely replicating the irradiation schedules in clinical practice and, to some extent, contributing to the understanding of growth rate or remission of tumors and the development of fibrosis.

Hypofractionated versus conventional intensity-modulated radiation irradiation (HARVEST-adjuvant): study protocol for a randomised non-inferior multicentre phase III trial

INTRODUCTION

Short course regimen has become the major trend in the field of adjuvant radiotherapy for patients with breast cancer. Hypofractionated radiotherapy (HF-RT) regimen of 40-42.5 Gy in 15-16 fractions has been established as a preferred option for whole breast irradiation. However, few evidences of hypofractionated regional nodal irradiation (RNI), especially involving internal mammary nodes (IMNs), could be available during the era of intensity-modulated radiation therapy (IMRT). Against this background, we design this trial to explore the hypothesis that HF-RT regimen involving RNI (including infraclavicular, supraclavicular nodes and IMNs) will be non-inferior to a standard schedule by using IMRT technique.

METHODS AND ANALYSIS

This is an open-label randomised, non-inferior, multicentre phase III trial. Patients with breast cancer with an indication for RNI after breast conserving surgery or mastectomy are randomised at a ratio of 1:1 into the following two groups: hypofractionated regimen of 2.67 Gy for 16 fractions or conventional regimen of 2 Gy for 25 fractions. The dose was prescribed to ipsilateral chest wall or whole breast and RNI (including infraclavicular, supraclavicular nodes and IMNs, lower axilla if indicated). The trial plans to enrol a total of 801 patients and all patients will be treated using IMRT technique. The primary endpoint is 5-year locoregional recurrence. The secondary endpoints include 5-year distant metastasis free survival, invasive recurrence-free survival, overall survival, accumulative acute radiation-induced toxicity and accumulative late radiation-induced toxicity, cosmetic outcomes and quality of life.

ETHICS AND DISSEMINATION

The study has been approved by the Ethical Committee of Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine (version 2018-95-3) and approvals from ethical committee of each participating centre have also been obtained. Research findings will be submitted for publication in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT03829553.

Cost containment analysis and access to treatment associated with adopting hypofractionated radiation therapy from the Brazilian perspective

Background

Estimates show that breast cancer, the leading cause of cancer death in females worldwide, will continue to increase in incidence, highlighting the need for increased treatment capacity. While postoperative radiation therapy (RT) is commonly used to reduce recurrence and mortality, research has shown that moderately hypofractionated radiation therapy (HFRT) and 5-fraction HFRT are equally safe and effective and can reduce treatment costs. This study aimed to compare the cost of conventional RT (50Gy/25), moderately HFRT (40.05Gy/15), and 5-fraction HFRT (26Gy/5) for breast cancer patients in Brazil.

Methods

The cost of each RT regimen was calculated using the International Atomic Energy Agency's Radiotherapy Cost Estimator Tool. The potential annual savings were then estimated by applying the cost of each regime to the 2020 Brazilian cancer incidence rates.

Findings

The average costs per patient for 25 fractions, 15 fractions, and 5 fractions are $2,699.20, $1,711.98, and $929.81, respectively. The annual cost savings associated with treating 70% of patients with 15 fraction HFRT and 30% of patients with 5 fraction HFRT as compared to treating all patients with 25 fraction RT is $72,929,315.40. The estimated annual productivity of 1 LINAC machine for 25 fractions, 15 fractions, and 5 fractions is 338, 647, and 1,310 patients, respectively.

Interpretation

The cost analysis revealed decreased patients' costs and potential for increased EBRT access associated with HFRT in the Brazilian perspective.

Funding

None.

History of Technological Advancements towards MR-Linac: The Future of Image-Guided Radiotherapy

Image-guided radiotherapy (IGRT) enables optimal tumor targeting and sparing of organs-at-risk, which ultimately results in improved outcomes for patients. Magnetic resonance imaging (MRI) revolutionized diagnostic imaging with its superior soft tissue contrast, high spatiotemporal resolution, and freedom from ionizing radiation exposure. Over the past few years there has been burgeoning interest in MR-guided radiotherapy (MRgRT) to overcome current challenges in X-ray-based IGRT, including but not limited to, suboptimal soft tissue contrast, lack of efficient daily adaptation, and incremental exposure to ionizing radiation. In this review, we present an overview of the technologic advancements in IGRT that led to MRI-linear accelerator (MRL) integration. Our report is organized in three parts: (1) a historical timeline tracing the origins of radiotherapy and evolution of IGRT, (2) currently available MRL technology, and (3) future directions and aspirations for MRL applications.

Optimal radiotherapy after breast-conserving surgery for early breast cancer: A network meta-analysis of 23,418 patients

PURPOSE

In order to explore whether partial breast irradiation can replace hypofractionated whole breast irradiation and whether the former two are superior to conventional fractionated whole breast irradiation, we conducted a network meta-analysis based on the data from the latest randomized controlled trials to evaluate the efficacy of these radiotherapy modalities.

MATERIAL AND METHODS

Data from eligible studies were analyzed to determine the published events for ipsilateral breast tumor recurrence, distant metastasis, total deaths, and non-breast cancer-related deaths. In the case of low or high heterogeneity, the fixed-effect or random-effect model was used for statistical analysis respectively. NMA was performed by using the node-splitting model for two-category data among three radiotherapies based on a Bayesian method.

RESULTS

A total of 23,418 patients were included in 16 studies. For ipsilateral breast tumor recurrence, both pairwise (OR=1.9; CI95%: 1.2 -2.8; p<0.05) and indirect (OR=1.7; CI95%: 1.2 -2.4; p<0.05) comparison of three radiotherapies by network meta-analysis showed that conventional fractionated whole breast irradiation was significantly better than partial breast irradiation. Indirect comparison of three radiotherapies by network meta-analysis showed that hypofractionated whole breast irradiation was significantly better than partial breast irradiation (OR=1.6; CI95%: 1.0 -2.5; p<0.05). Network and paired meta-analyses found no significant differences in other endpoints among the three radiotherapies.

CONCLUSION

Overall, this network meta-analysis showed that partial breast irradiation was related to the increase of ipsilateral breast tumor recurrence compared with hypofractionated or conventional fractionated whole breast irradiation in patients with early-stage breast cancer.

Moderately hypofractionated radiation therapy for breast cancer: A Brazilian cohort study

Background

Results from numerous clinical trials have led to a consensus that moderately hypofractionated radiation therapy is the ideal postoperative irradiation treatment plan in patients with breast cancer (BC). However, there are specific situations such as chest wall (with or without breast reconstruction) and regional node irradiation that still face obstacles in its widespread use. There is a lack of evidence supporting the use of moderately hypofractionated irradiation from the Latin American context. This study aims to describe the profile and clinical outcomes of patients treated with moderate hypofractionation for both early-stage (Stage I and II) and locally advanced BC (Stage III) regardless of the type of surgery in a Brazilian Oncology Center.

Methods

All patients with non-metastatic BC who were treated with moderately hypofractionated schedules of 40Gy in 15 fractions or 42.4Gy in 16 fractions between 2010 to 2019 at Hospital Sírio-Libanês, Brazil were retrospectively analyzed. The rates of local recurrence-free survival (LRFS), regional recurrence-free survival (RRFS), distance recurrence-free survival (DRFS) and overall survival (OS) were estimated. Acute and late toxicity profiles were accessed for the entire cohort.

Findings

A total of 670 patients were included. The median age was 57 years and the median follow-up time was 31 months. Most of the patients had stage I and II breast cancer, and 81.6% underwent breast-conserving surgery. Of the 123 women who underwent mastectomy treatment, 29% (n = 37) had immediate reconstruction with implants and 28% (n = 35) with autologous tissue. Seventy-one per cent of the patients presented luminal subtype tumour and 84.3% received adjuvant hormonal therapy. Chemotherapy was administered to almost half of the patients and all 80 patients with Her-2 positive disease received trastuzumab-based systemic therapy. One-third of patients received regional node irradiation; boost was performed in 41.1% of treatments. The 5-year LRFS, RRFS, DRFS and OS was 95.6%, 97.6%,92.2% and 95.9%, respectively. Acute and late side effects profile were mild and only 2.9% of patients developed grade 3 dermatitis. Among patients with breast implants, 11.4% had capsular contracture.

Interpretation

In this Brazilian institution experience, moderately hypofractionated irradiation to the breast, chest wall (with or without breast reconstruction), and regional lymph nodes was safe and with an acceptable toxicity profile.

Funding

None.

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.

Outcomes and toxicity following post-operative hypofractionated radiotherapy to the regional nodes and the breast or the chest wall in locally advanced breast cancer

OBJECTIVES

We aimed to analyze the impact of a 3-week schedule of HypoFractionated (HF) radiotherapy (RT) after axillary dissection and breast surgery, in terms of safety and efficacy in patients with locally advanced breast cancer (BC).

METHODS

Eligible patients were females with Stage IIA - IIIC BC who underwent axillary dissection and breast surgery, either quadrantectomy or mastectomy. HF RT was delivered in 15 or 16 fractions for a total dose of 40.05 Gy or 42.56 Gy, respectively, to the clavicular nodal region along with the whole breast (HF WBRT) or the chest wall (HF PMRT), according to the type of surgery. Locoregional recurrence (LRR), distant metastases-free survival (DMFS), overall survival (OS) and acute and late treatment-related toxicities were estimated.

RESULTS

57 patients with a median age of 60 years (32-85) were retrospectively analyzed. 34 (60%) of patients underwent breast conservative surgery in the form of quadrantectomy and 23 (40%) were offered radical mastectomy. All patients underwent hypofractionated regional nodal irradiation (HF RNI). 34 (60%) of them underwent HF WBRT, while 23 (40%) received HF PMRT.At a median follow-up of 80 months (30-113), the 7-year LRR-free survival was 93% (95% CI, 74%-95%). The same features for DMFS and OS were 76% (95% CI, 52%-78%) and 67% (95% CI, 50%-80%), respectively. Only one (2%) patient experienced G3 acute skin toxicity. No grade ≥2 late toxicity was observed.

CONCLUSION

Our study shows that HF RNI with HF RT to the whole breast or the chest wall after breast surgery is safe and effective in patients with locally advanced BC. Longer follow-up is needed to strengthen further analyses on late toxicity and clinical outcomes.

ADVANCES IN KNOWLEDGE

This paper adds to the evidence that post-operative RNI with WBRT or PMRT can be safely and effectively delivered with 3-week HF regimen. Locally advanced BC patients can be offered HF RT to the regional nodes and the breast or the chest wall regardless the type of surgery.

Comparison of Heart and Lung Doses According to Tumor Bed Boost Techniques in Early-Stage Left-Sided Breast Cancer: Simultaneous Integrated Boost versus Sequential Boost

Background and Objectives: The boost dose to the tumor bed after whole breast irradiation (WBI) can be divided into sequential boost (SEQ) and simultaneous integrated boost (SIB). SIB using modern radiation therapy (RT) techniques, such as volumetric modulated arc therapy, allow the delivery of a highly conformal dose to the target volume and has a salient ability to spare at-risk organs. This study aimed to compare the radiation dose delivered to the heart and lungs according to boost technique and tumor bed location. Materials and Methods: RT planning data of 20 patients with early-stage left-sided breast cancer were used in this study. All patients were treated with volumetric modulated arc therapy after breast-conserving surgery with a sentinel lymph node biopsy. For each patient, two different plans, whole breast irradiation with simultaneous integrated boost (WBI-SIB) and sequential boost after WBI (WBI-SEQ), were generated. To compare the dose received by each organ at risk (OAR), dose-volume histogram data were analyzed. The mean dose (Dmean) and volume of each organ that received x Gy (Vx) were calculated and compared. Results: For the heart, the V10 was lower for the WBI-SIB plan than for the WBI-SEQ plan (5.223 ± 1.947% vs. 6.409 ± 2.545%, p = 0.008). For the left lung, the V5 was lower in the WBI-SIB plan than for the WBI-SEQ plan (27.385 ± 3.871% vs. 32.092 ± 3.545%, p < 0.001). The Dmean for the heart and left lung was lower for the WBI-SIB plan than for the WBI-SEQ plan (heart: 339.745 ± 46.889 cGy vs. 413.030 ± 52.456 cGy, p < 0.001; left lung: 550.445 ± 65.094 cGy vs. 602.270 ± 55.775 cGy, p < 0.001). Conclusions: The WBI-SIB plan delivered lower radiation doses to the heart and left lung than the WBI-SEQ plan in terms of Dmean and low-dose volume in hypofractionated RT of early-stage left-sided breast cancer patients. Furthermore, a large radiation dose per day may be advantageous, considering the radiobiologic aspects of breast cancer. Long-term follow-up data are needed to determine whether the dosimetric advantages of the WBI-SIB plan can lead to clinically improved patient outcomes and reduced late side effects.

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.

Favorable safety profile of moderate hypofractionated over normofractionated radiotherapy in breast cancer patients: a multicentric prospective real-life data farming analysis

Background

Moderately hypofractionated whole-breast radiotherapy (HFRT) has proven to be as safe and efficient as normofractionated radiotherapy (NFRT) in randomized trials resulting in major changes in clinical practice. Toxicity rates observed in selected clinical trial patients may differ from those observed in unselected patients with possible comorbidities and frailty in real-life. This study aimed to examine the influence of HFRT versus NFRT on acute toxicity and identify risks factors of dermatitis in real-life patients.

Materials and methods

Prospective data from breast cancer patients, treated with locoregional radiotherapy were collected between November 2015 and February 2020 in 3 comprehensive cancer centers. Through a systematic data-farming strategy, acute toxicity evaluation forms (CTCAEv4.0) were prospectively completed and extracted electronically. The results from each center were then anonymously merged into a single database for analysis. A Chi-2 test was used to compare HFRT and NFRT. Furthermore, risk factors of dermatitis were identified in a sub-study (622 patients) by multivariate logistic regression analysis.

Results

In total, 3518 T0-4 N0-3 mostly M0 (85.8%) breast cancer patients with a median age of 60.7 (24–96 years old) were analyzed. Acute grade 2–3 dermatitis, grade 1–3 breast oedema, and grade 1–2 hyperpigmentation were less frequent with HFRT versus NFRT: respectively 8.9% versus 35.1% (Chi-2 = 373.7; p < 0.001), 29.0% versus 37.0% (Chi-2 = 23.1; p < 0.001) and 27.0% versus 55.8% (Chi-2 = 279.2; p < 0.001). Fewer patients experienced pain with HFRT versus NFRT: 33.4% versus 53.7% respectively (Chi-2 = 137.1; p < 0.001). Factors such as high BMI (OR = 2.30 [95% CI, 1.28–4.26], p < 0.01), large breast size (OR = 1.88 [95% CI, 1.07–3.28], p < 0.01) and lumpectomy over mastectomy (OR = 0.52 [95% CI, 0.27–0.97], p < 0.05) were associated with greater risk factors of grade 2–3 dermatitis in multivariate analysis regardless of NFRT or HFRT.

Conclusion

The results of this study suggests that breast HFRT may be a better option even for patients with a high BMI or large breast size. Acute toxicity was low to mild, and lower with HFRT compared to NFRT. Results from real-life data were robust, and support the use of HFRT beyond randomized study populations. Long-term real-life data awaits further investigation.

Factors Associated with Late Local Radiation Toxicity after Post-Operative Breast Irradiation

Purpose. To assess determinants associated with late local radiation toxicity in patients treated for breast cancer. Methods. A systematic review was performed. All studies reporting ≥2 variables associated with late local radiation toxicity after treatment with postoperative whole breast irradiation were included. Cohort studies, randomized controlled trials, and cross-sectional studies were eligible designs. Study characteristics and definitions of determinants and outcome measures were extracted. If possible, the measure of association was extracted. Results. Twenty-one studies were included in this review. Six out of seven studies focused on the association between radiotherapy (boost) dose or irradiated breast volume and late radiation toxicity found significant results. Tumor bed boost was associated with late radiation toxicity, fibrosis, and/or edema in six out of twelve studies. Lower age was associated with late breast toxicity in one study, while in another study, higher age was significantly associated with breast fibrosis. Also, no association between age and late radiation toxicity was found in eight out of twelve studies. Similar inconsistent results were found in the association between late radiation toxicity and other patient-related factors (i.e., breast size, diabetes mellitus) and surgical and systemic treatment-related factors (i.e., complications after surgery, chemotherapy, and time between surgery and radiotherapy). Conclusion. In modern 3D radiotherapy, radiotherapy (boost) dose and volume are—like in 2D radiotherapy—associated with late local radiation toxicity, such as breast fibrosis and edema. Treatment de-escalation, for example, partial breast irradiation in selected patients might be important to decrease late local toxicity without compromising locoregional control and survival.

Four-fraction ultra-accelerated minimal breast irradiation in early breast cancer: The initial feasibility results of an institutional experience

PURPOSE

To evaluate the feasibility, early toxicity, and clinical outcomes of early-breast cancer patients in a single-arm, phase I/II study of an ultra-accelerated, four-fraction schedule of minimal breast irradiation (4f-AMBI) using a multicatheter, minimally-invasive, intraoperative tumor bed implant (MITBI) during breast-conserving surgery (BCS).

METHODS AND MATERIALS

Eligible women aged >40 years with clinically and radiologically confirmed, unifocal invasive or in situ ≤3 cm tumors were considered as potential candidates for MITBI during BCS. After the pathology report, patients who met APBI criteria received ultra-accelerated four-fractions irradiation (6.2 Gy BID x 4fx over 2 days) with perioperative HDR-brachytherapy (PHDRBT). Early complications, toxicity, clinical outcomes, and cosmetic results were analyzed.

RESULTS

Of 89 patients initially implanted, 60(67.4%) were definitively included in the 4f-AMBI-protocol. The median age was 64.4 years; the median CTV was 32.1 cc (6.9-75.4 cc), and the external-V₁₀₀ was 43.1 cc (12.87-107 cc), representing 5% of the breast tissue irradiated with a median CTV D₉₀ of 6.2 Gy (5.6-6.28 Gy). The entire local treatment (BCS&MITBI-4f-AMBI) was completed at a median of 8 days (4-10 days). The rate of early complications was 11%. There were no major complications. Acute skin-subcutaneous G1 toxicity was reported in 11.7%, and late G1 toxicity on 36.7%. After a median follow-up of 27 months (11-51 months), the local, elsewhere, locoregional and distant-control rates were 100%, 98.3%, 100%, and 100% respectively. The early-cosmetic evaluation was excellent-good in 94.5% of patients evaluated.

CONCLUSIONS

Ultra-accelerated, four-fraction, minimal breast irradiation (4f-AMBI) using a minimally-invasive tumor bed implant procedure is safe, dosimetrically feasible, and shows small irradiated volumes. This program provides low toxicity rates and excellent short-term clinical and cosmesis outcomes.

Moderately hypofractionated post-operative radiation therapy for breast cancer: Systematic review and meta-analysis of randomized clinical trials

Introduction

We provide a critical assessment regarding current evidence for the use of moderately hypofractionated irradiation for patients with breast cancer. The aim of the study was to summarize the available evidence regarding outcomes after moderately hypofractionated compared with conventional radiation doses in the post-operative treatment of patients with breast cancer.

Material and methods

The Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE and LILACS databases were searched until March 25, 2021. All randomized phase 3 clinical trials that compared moderately hypofractionated with conventional radiation doses in the post-operative treatment of patients with breast cancer were selected. This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statement.

Results

Eight clinical trials satisfied the eligibility criteria and were the focus of the analysis. A total of 12,139 breast cancer patients was randomly assigned for moderately hypofractionated compared with conventional irradiation. Meta-analysis of the trials regarding local recurrence, loco-regional recurrence, disease-free survival, and overall survival outcomes did not demonstrate any significant difference between moderately hypofractionated irradiation and conventional radiation doses groups. The rate of severe side effects was low in both groups; acute and late side effects and cosmesis were similar or even tended to be lower after moderately hypofractionated than after conventional irradiation.

Conclusions

Moderately hypofractionated is at least as effective and safe as conventional radiation irradiation regimens and should be considered as a treatment option for most, if not all, breast cancer patients.

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Evidence for the use of moderately hypofractionated RT (MHRT) for breast cancer.

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Meta-analysis of clinical trials.

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MHRT is at least as safe and effective as conventionally fractionated regimens.