Volume matters: Breast induration is associated with irradiated breast volume in the Danish Breast Cancer Group phase III randomized Partial Breast Irradiation trial

Cosmetic outcome in patients with early stage breast cancer after accelerated partial breast irradiation using intraoperative or external beam radiotherapy

Purpose

The aim of this study is to evaluate the cosmetic outcome among early stage breast cancer patients who underwent accelerated partial breast irradiation with either intraoperative electron radiotherapy (IOERT) or photon external beam radiotherapy (EB-APBI).

Materials and methods

This prospective multicenter cohort study enrolled women aged 60 years and older who underwent breast-conserving therapy. Following breast-conserving surgery, patients were treated with either IOERT or EB-APBI. Cosmetic outcome was evaluated over a 5 year follow-up period using both subjective scoring by patients and physicians, as well as objective scoring using BCCT.core software. Differences between treatments over time were described with mixed model analyses.

Results

A total of 241 patients treated with IOERT and 164 patients treated with EB-APBI were eligible for cosmetic analysis. In both groups, the majority of patients reported a satisfactory cosmetic outcome, with no significant differences between treatments over time (p = 0.538). This was also observed by physicians, with satisfactory outcomes ranging from 94 % (170/181) to 91 % (69/76) over time in the IOERT group and from 93 % (124/133) to 95 % (54/57) in the EB-APBI group (p = 0.579). BCCT.core analysis returned satisfactory cosmetic outcomes in 75 % (54/72) of the IOERT patients at 3 years and in 77 % (20/26) at 5 years. These numbers were 86 % (72/84) and 90 % (36/40) for the EB-APBI patients, with no significant differences between treatment over time (p = 0.834).

Conclusion

Regarding the cosmetic results, IOERT and EB-APBI yield comparable and satisfactory outcomes over 5 years follow-up in the treatment of early stage breast cancer.

Breast induration and irradiated volume in the DBCG HYPO trial: The impact of age, smoking, and boost

PURPOSE

To investigate the association between irradiated breast volume and grade 2-3 breast induration three years after radiotherapy in the phase III Danish Breast Cancer Group HYPO trial randomizing patients ≥ 41 years to whole breast irradiation (WBI) with 40 Gy/15fr versus 50 Gy/25fr.

METHODS

Treatment plans were available for all Danish patients. Associations between frequency of induration and irradiated volume, age, smoking status, and boost were assessed by logistic regression. A sequential boost was given to patients < 50 years or in case of a Narrow (<2 mm) resection margin.

RESULTS

RT plans from 1,333 patients were analyzed with 178 (13 %) having grade 2-3 induration. 1135 patients had only WBI. For this group, induration was correlated with irradiated breast volume for patients ≥ 65 years (n = 343, 10 %/22 % for small/large irradiated volumes, p = 0.005) but not for patients aged 50-64 years (n = 792, 11 % for both small and large volumes, p = 0.82). Smoking doubled the frequency irrespective of irradiated volume and age. All patients < 50 years (n = 156) had a boost. A volume effect was found for this group (5 %/21 % induration for small/large volume, p = 0.002). 42 patients ≥ 50 years had a boost and 14 (33 %) had grade 2-3 induration, however, with a p-value > 0.05 due to the few numbers of patients.

CONCLUSION

A relationship between irradiated breast volume and 3-year frequency of breast induration was found for patients ≥ 65 years, whilst not for patients aged 50-64 years. Smoking doubled the risk of induration irrespective of volume and age. A dose-induration relationship was seen for boost patients < 50 years.

The Assisi think tank focus review on postoperative radiation for lobular breast cancer

The "Assisi Think Tank Meeting" (ATTM) on Breast Cancer, endorsed by the European Society for Radiotherapy & Oncology (ESTRO) and the Italian Association of Radiotherapy and Clinical Oncology (AIRO), and conducted under the auspices of the European Society of Breast Cancer Specialists (EUSOMA), is a bi-annual meeting aiming to identify major clinical challenges in breast cancer radiation therapy (RT) and proposing clinical trials to address them. The topics discussed at the meeting are pre-selected by the steering committee. At the meeting, these topics are discussed in different working groups (WG), after preparation of the meeting by performing a systematic review of existing data and of ongoing trials. Prior to the meeting, each WG designs a survey on the topic to be discussed to reflect current clinical practice and to identify areas requiring further research. Herein, we present the work done by the Assisi WG focusing on lobular carcinoma and the RT perspectives in its treatment, including providing recommendations for locoregional therapy, mainly RT for patients with non-metastatic lobular breast cancer.

Dosimetric Analyses of the Three Radiation Techniques Used in the EORTC 22922/10925 IM-MS Breast Cancer Trial

PURPOSE

The aim of the current study is to compare the dosimetry of 3 radiation therapy (RT) techniques used in the EORTC 22922/10925 trial for irradiating the internal mammary (IM) and medial supraclavicular nodes (MS) using a treatment planning system available nowadays for dose calculation.

METHODS

We performed a retrospective dosimetry analysis of anonymised data; thus, ethics approval was not required. Ten cases of left-sided breast were randomly selected for RT planning to a total dose of 50 Gy in 25 fractions. The treatment planning was done according to the trial's protocol and under the supervision of the EORTC trial's coordinators. Doses to planning target volumes (PTV) and to organs at risk (OARs) are reported. Data is presented in descriptive statistics.

RESULTS

A total of 10 cases and 40 treatment plans (4 plans per case: standard-plan A, modified standard-plan B, individualised-plan C and breast-only-plan D). For all planning techniques, the mean dose to the PTV of the left breast (plan A-D) and the PTV-MS (plan A-C) exceeded 95% of the prescribed dose (>47.5 Gy). The individualised technique (plan C) had a lower coverage for PTV-IM, with a mean of 87% of the prescribed dose compared to ∼102% for plans A and B. The dose to OARs varied between techniques, with the mean heart dose being higher in the standard and modified standard techniques (18.3 and 16.6 Gy, respectively) compared to the individualised technique (9.5 Gy).

CONCLUSIONS

The 3 RT techniques used in the trial varied in target coverage and OARs dose. Our results may help to understand the observed larger absolute benefit of individualised IM-MS treatment planning in terms of breast cancer outcomes.

Hypofractionated Partial Breast Reirradiation in the Conservative Retreatment of Breast Cancer Local Recurrence

PURPOSE

To evaluate the outcome of partial breast reirradiation (re-PBI) with intensity modulated radiation therapy using a hypofractionated scheme for breast cancer (BC) local relapse (LR) operated on with repeat breast-conservative surgery.

METHODS AND MATERIALS

Intensity modulated radiation therapy-based re-PBI was performed using either helical or step-and-shoot modality to deliver 37.05 Gy in 13 fractions in 2.5 weeks. Cumulative incidence of second LR, toxicity, disease-free survival (DFS), BC-specific survival, and overall survival were evaluated.

RESULTS

Between May 2012 and May 2021, 70 patients had re-PBI. The median follow-up (FU) was 6.3 years (quartiles 1-3, 4.0-8.1.). The median age at first LR was 62 years. The median primary BC first LR interval was 12.4 years (range, 1.6-26.7 years). Luminal A-like first LR accounted for 41% of the cases, and the median size was 0.8 cm. During FU, 18 (26%) patients showed a subsequent event: 3 second LRs (corresponding to an 8-year cumulative rate of 4%), 3 regional nodal recurrences, 7 distant metastases, and 5 other primary tumors. At 8 years, DFS, BC-specific survival, and overall survival were 76%, 90%, and 90%, respectively. At multivariate analysis, grade 3 and extensive intraductal components were independent predictors for DFS. For 51 and 46 patients, chronic toxicity and cosmesis were evaluated, respectively: 4% had grade 3 fibrosis, and cosmesis was deemed good/excellent in just >60% of the cases.

CONCLUSIONS

Re-PBI after repeat breast-conservative surgery represents a feasible alternative to mastectomy with regard to local control, showing an acceptable toxicity profile. A long-term FU is crucial to better understand the pattern of relapse and consolidate the position of re-PBI in clinical practice.

Locoregional Ablative Radiation Therapy for Patients With Breast Cancer Unsuitable for Surgical Resection

PURPOSE

Patients with breast cancer who are unsuitable for surgical resection are typically managed with palliative systemic therapy alone. We report outcomes of 5-fraction ablative radiation therapy for nonresected breast cancers.

METHODS AND MATERIALS

This is a retrospective analysis of an institutional registry of patients with breast cancer who were unsuitable for resection and underwent 35 to 40 Gy/5 fractions to the primary breast tumor or regional lymph nodes from 2014 to 2021. Primary outcomes were cumulative incidence of local failure and grade ≥3 toxicity (Common Terminology Criteria for Adverse Events, version 5.0).

RESULTS

We reviewed 57 patients who received 61 treatment courses (median age of 81 years; range, 38-99). Unresectable tumor (10%), patient refusal (18%), medical inoperability (35%), and metastatic disease (37%) were the causes of not having surgery. Five patients (8%) had previously undergone adjuvant locoregional radiation therapy. Fifty-four percent (n = 33/61) of treatment courses targeted the breast only, 31% (n = 19/61) both the breast and lymph nodes, and 15% (n = 9/61) the lymph nodes only. Sixty-seven percent (n = 35/52) of the courses that targeted the breast were delivered with partial breast irradiation and 33% (n = 17/52) with whole breast radiation therapy (median dose of 25 Gy in 5 fractions) ± simultaneous integrated boost to the primary tumor. Most primary tumors (65%, n = 34/52) and target lymph nodes (61%, n = 17/28) were treated with a dose of 35 Gy in 5 fractions. Most treatments (52%) were delivered with intensity modulated radiation therapy (IMRT). Radiation therapy was delivered daily (20%), every other day (18%), twice weekly (36%), or weekly (26%). The 2-year cumulative incidence of local failure was 11.4% and grade≥3 toxicity was 15.1%. The grade ≥3 toxicity was 6.5% for IMRT treatments, versus 7.7% for non-IMRT treatments targeting partial breast or lymph nodes (hazard ratio, 1.13, P = .92), versus 38.9% for non-IMRT treatments targeting the entire breast (hazard ratio, 6.91, P = .023). All grade ≥3 toxicity cases were radiation dermatitis. No cases of brachial plexopathy were observed.

CONCLUSIONS

Thirty-five to 40 Gy in 5 fractions is a safe and effective breast stereotactic body radiation therapy (SBRT) regimen and may be an attractive option for patients who are not surgical candidates. Highly conformal techniques (ie, IMRT or partial breast irradiation) were associated with a reduced risk of toxicity and should be the preferred treatment approaches.

Essential requirements for reporting radiation therapy in breast cancer clinical trials: An international multi-disciplinary consensus endorsed by the European Society for Radiotherapy and Oncology (ESTRO)

The European Society for Radiotherapy and Oncology (ESTRO) has advocated the establishment of guidelines to optimise precision radiotherapy (RT) in conjunction with contemporary therapeutics for cancer care. Quality assurance in RT (QART) plays a pivotal role in influencing treatment outcomes. Clinical trials incorporating QART protocols have demonstrated improved survival rates with minimal associated toxicity. Nonetheless, in routine clinical practice, there can be variability in the indications for RT, dosage, fractionation, and treatment planning, leading to uncertainty. In pivotal trials reporting outcomes of systemic therapy for breast cancer, there is limited information available regarding RT, and the potential interaction between modern systemic therapy and RT remains largely uncharted. This article is grounded in a consensus recommendation endorsed by ESTRO, formulated by international breast cancer experts. The consensus was reached through a modified Delphi process and was presented at an international meeting convened in Florence, Italy, in June 2023. These recommendations are regarded as both optimal and essential standards, with the latter aiming to define the minimum requirements. A template for a case report form (CRF) has been devised, which can be utilised by all clinical breast cancer trials involving RT. Optimal requirements include adherence to predefined RT planning protocols and centralised QART. Essential requirements aim to reduce variations and deviations from the guidelines in RT, even when RT is not the primary focus of the trial. These recommendations underscore the significance of implementing these practices in both clinical trials and daily clinical routines to generate high-quality data.

Skin dose-volume predictors of moderate-severe late side effects after whole breast radiotherapy

BACKGROUND

Toxicity after whole breast Radiotherapy is a relevant issue, impacting the quality-of-life of a not negligible number of patients. We aimed to develop a Normal Tissue Complication Probability (NTCP) model predicting late toxicities by combining dosimetric parameters of the breast dermis and clinical factors.

METHODS

The skin structure was defined as the outer CT body contour's 5 mm inner isotropic expansion. It was retrospectively segmented on a large mono-institutional cohort of early-stage breast cancer patients enrolled between 2009 and 2017 (n = 1066). Patients were treated with tangential-field RT, delivering 40 Gy in 15 fractions to the whole breast. Toxicity was reported during Follow-Up (FU) using SOMA/LENT scoring. The study endpoint was moderate-severe late side effects consisting of Fibrosis-Atrophy-Telangiectasia-Pain (FATP G ≥ 2) developed within 42 months after RT completion. A machine learning pipeline was designed with a logistic model combining clinical factors and absolute skin DVH (cc) parameters as output.

RESULTS

The FATP G2 + rate was 3.8 %, with 40/1066 patients experiencing side effects. After the preprocessing of variables, a cross-validation was applied to define the best-performing model. We selected a 4-variable model with Post-Surgery Cosmetic alterations (Odds Ratio, OR = 7.3), Aromatase Inhibitors (as a protective factor with OR = 0.45), V20 Gy (50 % of the prescribed dose, OR = 1.02), and V42 Gy (105 %, OR = 1.09). Factors were also converted into an adjusted V20Gy.

CONCLUSIONS

The association between late reactions and skin DVH when delivering 40 Gy/15 fr was quantified, suggesting an independent role of V20 and V42. Few clinical factors heavily modulate the risk.

Benefit of respiratory gating in the Danish Breast Cancer Group partial breast irradiation trial

BACKGROUND AND PURPOSE

Partial breast irradiation (PBI)has beenthe Danish Breast Cancer Group(DBCG) standard for selected breast cancer patients since 2016 based onearlyresults from the DBCG PBI trial.During trial accrual, respiratory-gated radiotherapy was introduced in Denmark. This study aims to investigate the effect of respiratory-gating on mean heart dose (MHD).

PATIENTS AND METHODS

From 2009 to 2016 the DBCG PBI trial included 230 patientswith left-sided breast cancer receiving external beam PBI, 40 Gy/15 fractions/3 weeks.Localization of the tumor bed on the planning CT scan, the use of respiratory-gating, coverage of the clinical target volume (CTV), and doses to organs at risk were collected.

RESULTS

Respiratory-gating was used in 123 patients (53 %). In 176 patients (77 %) the tumor bed was in the upper and in 54 patients (23 %) in the lower breast quadrants. The median MHD was 0.37 Gy (interquartile range 0.26-0.57 Gy), 0.33 Gy (0.23-0.49 Gy) for respiratory-gating, and 0.49 Gy (0.31-0.70 Gy) for free breathing, p < 0.0001. MHD was < 1 Gy in 206 patients (90 %) and < 2 Gy in 221 patients (96 %). Respiratory-gating led to significantly lower MHD for upper-located, but not for lower-located tumor beds, however, all MHD were low irrespective of respiratory-gating. Respiratory-gating did not improve CTV coverage or lower lung doses.

CONCLUSIONS

PBI ensured a low MHD for most patients. Adding respiratory-gating further reduced MHD for upper-located but not for lower-located tumor beds but did not influence target coverage or lung doses. Respiratory-gating is no longer DBCG standard for left-sided PBI.

Toxicity of external beam accelerated partial-breast irradiation (APBI) in adjuvant therapy of early-stage breast cancer: prospective randomized study

BACKGROUND

Accelerated partial breast irradiation (APBI) is an alternative breast-conserving therapy approach where radiation is delivered in less time compared to whole breast irradiation (WBI), resulting in improved patient convenience, less toxicity, and cost savings. This prospective randomized study compares the external beam APBI with commonly used moderate hypofractionated WBI in terms of feasibility, safety, tolerance, and cosmetic effects.

METHODS

Early breast cancer patients after partial mastectomy were equally randomized into two arms- external APBI and moderate hypofractionated WBI. External beam technique using available technical innovations commonly used in targeted hypofractionated radiotherapy to minimize irradiated volumes was used (cone beam computed tomography navigation to clips in the tumor bed, deep inspiration breath hold technique, volumetric modulated arc therapy dose application, using flattening filter free beams and the six degrees of freedom robotic treatment couch). Cosmetics results and toxicity were evaluated using questionnaires, CTCAE criteria, and photo documentation.

RESULTS

The analysis of 84 patients with a median age of 64 years showed significantly fewer acute adverse events in the APBI arm regarding skin reactions, local and general symptoms during a median follow-up of 37 months (range 21-45 months). A significant difference in favor of the APBI arm in grade ≥ 2 late skin toxicity was observed (p = 0.026). Late toxicity in the breast area (deformation, edema, fibrosis, and pain), affecting the quality of life and cosmetic effect, occurred in 61% and 17% of patients in WBI and APBI arms, respectively. The cosmetic effect was more favorable in the APBI arm, especially 6 to 12 months after the radiotherapy.

CONCLUSION

External APBI demonstrated better feasibility and less toxicity than the standard regimen in the adjuvant setting for treating early breast cancer patients. The presented study confirmed the level of evidence for establishing the external APBI in daily clinical practice.

TRIAL REGISTRATION

NCT06007118.

Large institutional experience of early outcomes and dosimetric findings with postoperative stereotactic partial breast irradiation in breast cancer

PURPOSE

To analyze the dosimetric and toxicity outcomes of patients treated with postoperative stereotactic partial breast irradiation (S-PBI).

METHODS

We identified 799 women who underwent S-PBI at our institution between January 2016 and December 2022. The most commonly used dose-fraction and technique were 30 Gy in 5 fractions (91.7 %) and a robotic stereotactic radiation system with real-time tracking (83.7 %). The primary endpoints were dosimetric parameters and radiation-related toxicities. For comparison, a control group undergoing ultra-hypofractionated whole breast irradiation (UF-WBI, n = 468) at the same institution was selected.

RESULTS

A total of 815 breasts from 799 patients, with a median planning target volume (PTV) volume of 89.6 cm3, were treated with S-PBI. Treatment plans showed that the mean and maximum doses received by the PTV were 96.2 % and 104.8 % of the prescription dose, respectively. The volume of the ipsilateral breast that received 50 % of the prescription dose was 32.3 ± 8.9 %. The mean doses for the ipsilateral lung and heart were 2.5 ± 0.9 Gy and 0.65 ± 0.39 Gy, respectively. Acute toxicity occurred in 175 patients (21.5 %), predominantly of grade 1. Overall rate of late toxicity was 4 % with a median follow-up of 31.6 months. Compared to the UF-WBI group, the S-PBI group had comparably low acute toxicity (21.5 % vs. 25.2 %, p = 0.12) but significantly lower dosimetric parameters for all organs-at-risks (all p < 0.05).

CONCLUSION

In this large cohort, S-PBI demonstrated favorable dosimetric and toxicity profiles. Considering the reduced radiation exposure to surrounding tissues, external beam PBI with advanced techniques should at least be considered over traditional WBI-based approaches for PBI candidates.

Patient specific quality assurance of volumetric modulated arc therapy of synchronous bilateral breast cancer

Synchronous bilateral breast cancers (SBBC) present a considerable issue in external beam radiotherapy because of large fields size and large target volumes. Mono-isocentric volumetric modulated arc therapy (VMAT) appears as an appropriate irradiation technique for these types of tumors. The aim of this study was to demonstrate the utility of a 3D DVH pretreatment quality assurance program in VMAT of SBBC cases. Twenty SBBC patients who underwent radiation therapy in our department were retrospectively enrolled in this study. Fifteen patients were treated exclusively to the mammary glands. Five patients benefited from a dose boost on the tumor bed (60Gy). Nine patients were irradiated on the supraclavicular nodes (50Gy). This dose was delivered in 25 fractions and integrated boost was used when appropriate. Depending on the complexity of the treatment plans; 2 or 4 arcs VMAT plans were used in a mono-isocentric technique. The patient specific quality assurance (PSQA) was evaluated using COMPASS measured data, COMPASS reconstructed (CR) and COMPASS computed (CC) dose compared to treatment planning system (TPS) dose. Clinical evaluation was based on DVH metrics for target volumes and organ at risks. The maximum average dose deviation between TPS, CC, and CR was below 3%. The paired t-test between TPS, CC, and CR shows a strong agreement (p < 0.001). The 3DVH dose distribution comparison between TPS and COMPASS were also performed with good gamma score for global analysis. COMPASS was successfully evaluated as a 3DVH pretreatment system for SBBC despite the large fields size and complex target volumes. It allows the verification of the plan in 3D patient anatomy and the evaluation of dose discrepancies.

The King is in the altogether: Radiation therapy after oncoplastic breast surgery

Breast cancer is the most common malignancy, and the majority of the patients are diagnosed at an early disease stage. Breast conservation is the preferred locoregional approach, and oncoplastic breast conservation surgery is becoming more popular. This narrative review aims to discuss the challenges and uncertainties in target volume definition for postoperative radiation after these procedures, to improve radiation therapy decisions and encourage multidisciplinary.

A national repository of complete radiotherapy plans: design, Results, and experiences

BACKGROUND

Previously, many radiotherapy (RT) trials were based on a few selected dose measures. Many research questions, however, rely on access to the complete dose information. To support such access, a national RT plan database was created. The system focuses on data security, ease of use, and re-use of data. This article reports on the development and structure, and the functionality and experience of this national database.

METHODS AND MATERIALS

A system based on the DICOM-RT standard, DcmCollab, was implemented with direct connections to all Danish RT centres. Data is segregated into any number of collaboration projects. User access to the system is provided through a web interface. The database has a finely defined access permission model to support legal requirements.

RESULTS

Currently, data for more than 14,000 patients have been submitted to the system, and more than 50 research projects are registered. The system is used for data collection, trial quality assurance, and audit data set generation.Users reported that the process of submitting data, waiting for it to be processed, and then manually attaching it to a project was resource intensive. This was accommodated with the introduction of triggering features, eliminating much of the need for users to manage data manually. Many other features, including structure name mapping, RT plan viewer, and the Audit Tool were developed based on user input.

CONCLUSION

The DcmCollab system has provided an efficient means to collect and access complete datasets for multi-centre RT research. This stands in contrast with previous methods of collecting RT data in multi-centre settings, where only singular data points were manually reported. To accommodate the evolving legal environment, DcmCollab has been defined as a 'data processor', meaning that it is a tool for other research projects to use rather than a research project in and of itself.

Preoperative Partial Breast Irradiation in Patients with Low-Risk Breast Cancer: A Systematic Review of Literature

BACKGROUND

Preoperative instead of standard postoperative partial breast irradiation (PBI) after breast-conserving surgery (BCS) has the advantage of reducing the irradiated breast volume, toxicity, and number of radiotherapy sessions and can allow tumor downstaging. In this review, we assessed tumor response and clinical outcomes after preoperative PBI.

PATIENTS AND METHODS

We conducted a systematic review of studies on preoperative PBI in patients with low-risk breast cancer using the databases Ovid Medline, Embase.com, Web of Science (Core Collection), and Scopus (PROSPERO registration CRD42022301435). References of eligible manuscripts were checked for other relevant manuscripts. The primary outcome measure was pathologic complete response (pCR).

RESULTS

A total of eight prospective and one retrospective cohort study were identified (n = 359). In up to 42% of the patients, pCR was obtained and this increased after a longer interval between radiotherapy and BCS (0.5-8 months). After a maximum median follow-up of 5.0 years, three studies on external beam radiotherapy reported low local recurrence rates (0-3%) and overall survival of 97-100%. Acute toxicity consisted mainly of grade 1 skin toxicity (0-34%) and seroma (0-31%). Late toxicity was predominantly fibrosis grade 1 (46-100%) and grade 2 (10-11%). Cosmetic outcome was good to excellent in 78-100% of the patients.

CONCLUSIONS

Preoperative PBI showed a higher pCR rate after a longer interval between radiotherapy and BCS. Mild late toxicity and good oncological and cosmetic outcomes were reported. In the ongoing ABLATIVE-2 trial, BCS is performed at a longer interval of 12 months after preoperative PBI aiming to achieve a higher pCR rate.

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.

Optimising post-operative radiation therapy after oncoplastic and reconstructive procedures

Surgical techniques for breast cancer have been refined over the past decades to deliver an aesthetic outcome as close as possible to the contralateral intact breast. Current surgery further allows excellent aesthetic outcome even in case of mastectomy, by performing skin sparing or nipple sparing mastectomy in combination with breast reconstruction. In this review we discuss how to optimise post-operative radiation therapy after oncoplastic and breast reconstructive procedures, including dose, fractionation, volumes, surgical margins, and boost application.