Partial-breast irradiation versus whole-breast radiotherapy for early breast cancer: A systematic review and update meta-analysis

Stereotactic body radiotherapy using CyberKnife versus interstitial brachytherapy in accelerated partial breast irradiation on left-sided breast: A comparison of dosimetric characteristics and preliminary clinical results

INTRODUCTION

We compared the dosimetric characteristics of the target and organs at risk (OARs) as well as the preliminary clinical outcomes between two accelerated partial breast irradiation (APBI) techniques.

METHODS

Forty-four patients diagnosed with left-sided early breast cancer who underwent APBI using either interstitial brachytherapy (IB) or stereotactic body radiation therapy (SBRT) with CyberKnife (CK) were retrospectively reviewed. The dosimetric parameters of the target and OARs were compared. Preliminary clinical outcomes, including tumor control and acute toxicity, were analyzed.

RESULTS

Treatment plans with CK demonstrated a better cardiac dose-sparing effect. Radiation doses to the heart at V150cGy for the CK and IB groups were 24.4 % and 60.4 %, respectively (p < 0.001), while the mean heart doses for the CK and IB groups were 107.4 cGy and 204 cGy, respectively (p < 0.001). The heart D1c.c. and the ipsilateral lung received a lower dose in the IB group, without any significant differences. The median follow-up time in the CK and IB groups was 28.6 and 61.3 months, respectively. No patients died from either breast cancer or cardiac events during follow-up. A locoregional recurrence event at the neck occurred in one patient within the IB group.

CONCLUSIONS

APBI planned by CK was shown to have a better dose-sparing effect on the heart, as well as better conformity and homogeneity to the target. CK is a non-invasive treatment which showed minimal acute toxicity and promising tumor control.

A systematic review and meta-analysis of intraoperative electron radiation therapy delivered with a dedicated mobile linac for partial breast irradiation in early breast cancer

•PBI is valid alternative to WBI in patients at low-risk of local relapse. •PBI is delivered by means of various techniques, one of which is IOeRT. •After IOeRT, an unexpectedly high LR rate was observed in the only phase III RCT. •Patient selection impacts on LR rates after IOeRT. •With appropriate patient selection IOeRT outcomes overlap with other RT techniques.

Stabilised Hyaluronic Acid (sHA) gel as a novel marker for breast cancer tumour bed cavity: Surgical feasibility

Introduction

Consistent delineation of the breast conserving surgery (BCS) tumour bed (TB) for breast cancer remains a challenge for radiation oncologists. Accurate delineation allows for better local control and reduces toxicity when planning partial breast or TB boost radiation therapy (RT).

Methods

In the operating theatre (OT) breast surgeons inserted stabilised hyaluronic acid (sHA) gel as small drops approximately one cm into the walls surrounding the resection cavity. Surgical feasibility was determined by the rate of successful sHA gel insertion procedure, the ease of insertion as rated by surgeons, the time required for insertion procedure, the quantity used, and any adverse events (AE) relating to sHA gel insertion.

Results

Thirty-five patients were enrolled. All patients underwent sHA gel insertion successfully. The procedure added a median of 2.8 min to the OT time and was rated as 'easy' in 89 % of patients. There were no immediate AE in OT. Five (14 %) patients experienced a grade 2 or higher AE. Three of the five patients were prescribed oral antibiotics for breast infection. Two of the five patients experienced a grade 3 AE - haematoma which required evacuation in OT day 1 post-BCS, and infected seroma which required drainage and washout in OT 2 months post-BCS. All five patients recovered and underwent the planned adjuvant therapies for their BC. The AE data reflects common risks with standard BCS and are not clearly attributed to sHA gel insertion alone.

Conclusion

We show that sHA gel is surgically feasible as a marker to help define the TB cavity for post-BCS adjuvant MRI-based RT planning.

Accelerated partial breast irradiation using sole interstitial multicatheter brachytherapy compared with whole-breast irradiation with boost for early breast cancer: 10-year results of a GEC-ESTRO randomised, phase 3, non-inferiority trial

BACKGROUND

Several randomised, phase 3 trials have investigated the value of different techniques of accelerated partial breast irradiation (APBI) for patients with early breast cancer after breast-conserving surgery compared with whole-breast irradiation. In a phase 3 randomised trial, we evaluated whether APBI using multicatheter brachytherapy is non-inferior compared with whole-breast irradiation. Here, we present the 10-year follow-up results.

METHODS

We did a randomised, phase 3, non-inferiority trial at 16 hospitals and medical centres in Austria, Czech Republic, Germany, Hungary, Poland, Spain, and Switzerland. Patients aged 40 years or older with early invasive breast cancer or ductal carcinoma in situ treated with breast-conserving surgery were centrally randomly assigned (1:1) to receive either whole-breast irradiation or APBI using multicatheter brachytherapy. Whole-breast irradiation was delivered in 25 daily fractions of 50 Gy over 5 weeks, with a supplemental boost of 10 Gy to the tumour bed, and APBI was delivered as 30·1 Gy (seven fractions) and 32·0 Gy (eight fractions) of high-dose-rate brachytherapy in 5 days or as 50 Gy of pulsed-dose-rate brachytherapy over 5 treatment days. Neither patients nor investigators were masked to treatment allocation. The primary endpoint was ipsilateral local recurrence, analysed in the as-treated population; the non-inferiority margin for the recurrence rate difference (defined for 5-year results) was 3 percentage points. The trial is registered with ClinicalTrials.gov, NCT00402519; the trial is complete.

FINDINGS

Between April 20, 2004, and July 30, 2009, 1328 female patients were randomly assigned to whole breast irradiation (n=673) or APBI (n=655), of whom 551 in the whole-breast irradiation group and 633 in the APBI group were eligible for analysis. At a median follow-up of 10·36 years (IQR 9·12-11·28), the 10-year local recurrence rates were 1·58% (95% CI 0·37 to 2·8) in the whole-breast irradiation group and 3·51% (1·99 to 5·03) in the APBI group. The difference in 10-year rates between the groups was 1·93% (95% CI -0·018 to 3·87; p=0·074). Adverse events were mostly grade 1 and 2, in 234 (60%) of 393 participants in the whole-breast irradiation group and 314 (67%) of 470 participants in the APBI group, at 7·5-year or 10-year follow-up, or both. Patients in the APBI group had a significantly lower incidence of treatment-related grade 3 late side-effects than those in the whole-breast irradiation group (17 [4%] of 393 for whole-breast irradiation vs seven [1%] of 470 for APBI; p=0·021; at 7·5-year or 10-year follow-up, or both). At 10 years, the most common type of grade 3 adverse event in both treatment groups was fibrosis (six [2%] of 313 patients for whole-breast irradiation and three [1%] of 375 patients for APBI, p=0·56). No grade 4 adverse events or treatment-related deaths have been observed.

INTERPRETATION

Postoperative APBI using multicatheter brachytherapy after breast-conserving surgery in patients with early breast cancer is a valuable alternative to whole-breast irradiation in terms of treatment efficacy and is associated with fewer late side-effects.

FUNDING

German Cancer Aid, Germany.

Comparison of Clinical Outcomes Between Low- and High-Risk Groups of Early Breast Cancer Patients Treated with Intraoperative Radiotherapy in Addition to External Beam Radiation: A Multi-Centre Prospective Study

BACKGROUND

There is a paucity of data on the use of intraoperative radiotherapy (IORT) with low-energy X-rays in Malaysian women with early breast cancer. The aim of this study is to evaluate the clinical, cosmetic, and patient-reported outcomes in low- and high-risk early breast cancer patients treated with breast conserving surgery (BCS) and IORT.

METHODOLOGY

Patients suitable for BCS who were treated with IORT between January 2016 and June 2019 from three centres were analysed. They were divided into low-risk and high-risk groups based on the risk of recurrence according to the TARGeted Intraoperative radioTherapy (TARGIT) A and B study criteria. Outcomes of interest included local recurrence, wound complications, and radiation toxicity, with a subset analysed for cosmetic and patient-reported outcomes.

RESULTS

Within a median follow-up of 31 months, there were 104 and 211 patients in the low- and high-risk groups, respectively. No significant difference was observed in local recurrence rates (low-risk, 1.0% vs. high-risk, 1.4%; p = 1.000). Both cohorts exhibited low frequencies of severe wound complications ranging between 1.4 and 1.9%. No major radiation toxicities were reported in either group. In the subgroup analysis, low-risk patients had significantly better mean scores in the subscales of inframammary fold and scar. Based on the BREAST-Q patient-reported outcomes questionnaire, seven out of nine parameters were scored similarly between both groups with no significant difference.

CONCLUSION

This study showed that the use of IORT in both low- and high-risk early breast cancers is efficacious and safe with low recurrence rates and an acceptable toxicity profile.

Breast cancer: an up-to-date review and future perspectives

Breast cancer is the most common cancer worldwide. The occurrence of breast cancer is associated with many risk factors, including genetic and hereditary predisposition. Breast cancers are highly heterogeneous. Treatment strategies for breast cancer vary by molecular features, including activation of human epidermal growth factor receptor 2 (HER2), hormonal receptors (estrogen receptor [ER] and progesterone receptor [PR]), gene mutations (e.g., mutations of breast cancer 1/2 [BRCA1/2] and phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha [PIK3CA]) and markers of the immune microenvironment (e.g., tumor-infiltrating lymphocyte [TIL] and programmed death-ligand 1 [PD-L1]). Early-stage breast cancer is considered curable, for which local-regional therapies (surgery and radiotherapy) are the cornerstone, with systemic therapy given before or after surgery when necessary. Preoperative or neoadjuvant therapy, including targeted drugs or immune checkpoint inhibitors, has become the standard of care for most early-stage HER2-positive and triple-negative breast cancer, followed by risk-adapted post-surgical strategies. For ER-positive early breast cancer, endocrine therapy for 5-10 years is essential. Advanced breast cancer with distant metastases is currently considered incurable. Systemic therapies in this setting include endocrine therapy with targeted agents, such as CDK4/6 inhibitors and phosphoinositide 3-kinase (PI3K) inhibitors for hormone receptor-positive disease, anti-HER2 targeted therapy for HER2-positive disease, poly(ADP-ribose) polymerase inhibitors for BRCA1/2 mutation carriers and immunotherapy currently for part of triple-negative disease. Innovation technologies of precision medicine may guide individualized treatment escalation or de-escalation in the future. In this review, we summarized the latest scientific information and discussed the future perspectives on breast cancer.

European Society for Radiotherapy and Oncology Advisory Committee in Radiation Oncology Practice consensus recommendations on patient selection and dose and fractionation for external beam radiotherapy in early breast cancer

High-quality randomised clinical trials testing moderately fractionated breast radiotherapy have clearly shown that local control and survival is at least as effective as with 2 Gy daily fractions with similar or reduced normal tissue toxicity. Fewer treatment visits are welcomed by patients and their families, and reduced fractions produce substantial savings for health-care systems. Implementation of hypofractionation, however, has moved at a slow pace. The oncology community have now reached an inflection point created by new evidence from the FAST-Forward five-fraction randomised trial and catalysed by the need for the global radiation oncology community to unite during the COVID-19 pandemic and rapidly rethink hypofractionation implementation. The aim of this paper is to support equity of access for all patients to receive evidence-based breast external beam radiotherapy and to facilitate the translation of new evidence into routine daily practice. The results from this European Society for Radiotherapy and Oncology Advisory Committee in Radiation Oncology Practice consensus state that moderately hypofractionated radiotherapy can be offered to any patient for whole breast, chest wall (with or without reconstruction), and nodal volumes. Ultrafractionation (five fractions) can also be offered for non-nodal breast or chest wall (without reconstruction) radiotherapy either as standard of care or within a randomised trial or prospective cohort. The consensus is timely; not only is it a pragmatic framework for radiation oncologists, but it provides a measured proposal for the path forward to influence policy makers and empower patients to ensure equity of access to evidence-based radiotherapy.

Radiodermatitis and Fibrosis in the Context of Breast Radiation Therapy: A Critical Review

Simple Summary

Skin toxicity is the main complication during irradiation in the management of early-stage breast cancer. In some cases, it may cause treatment to stop. These toxicities may be acute (mainly radiodermatitis) and/or late (mainly fibrosis). Their understandings, their mechanisms of occurrence, as well as their management is indispensable in order to improve the management of these patients. Through this study we propose to provide a clear picture of these toxicities in relation to the modalities of radiotherapy, advances in their quantification, and management to help practitioners improve their knowledge and clinical practices on this topic.

Abstract

Background: Radiation therapy has been progressively improved in order to maintain a satisfactory tumour response, while reducing toxicity. We will review the incidence of radiodermatitis and fibrosis according to the various radiation and fractionation techniques. We will then focus on the various methods used to manage, prevent, and quantify this toxicity. Method: More than 1753 articles were identified using the various search terms. We selected 53 articles to answer the questions addressed in this study according to criteria set in advance. Result: The literature reports lower acute toxicity with IMRT compared to 3DCRT, but no significant differences in terms of late toxicities. Partial breast irradiation appears to be less effective in terms of local control with a higher rate of late toxicity. Intra operative radiation therapy appears to provide good results in terms of both local control and late toxicity. The hypofractionation has equivalent efficacy and safety to the normofractionated regimen, but with lower rates of radiodermatitis and fibrosis. The adddition of a boost, particularly a sequential boost, increases the risk of fibrosis and radiodermatitis during treatment. Conclusion: The development of IMRT has significantly reduced acute toxicity and has improved tolerability during treatment. Modified fractionation has reduced treatment time, as well as adverse effects.

Radiation-induced breast angiosarcoma: report of two patients after accelerated partial breast irradiation (APBI) and review of the literature

Background

Angiosarcoma may rarely complicate radiotherapy of breast cancer. This so-called radiation-induced angiosarcoma (RIAS) occurs in less than 0.3% of patients that underwent breast conservation surgeries, usually years after completion of radiotherapy.

Case presentation

we introduce two cases of invasive ductal carcinoma who underwent lumpectomy and accelerated partial breast irradiation (APBI) as an alternative protocol to whole breast irradiation (WBI). They received adjuvant partial breast radiotherapy on tumor cavity for a total dose of 38.5 Gy in 10 fractions in 5 days using 3D-external-beam RT. In both cases, RIAS occurred eight years after radiotherapy, in the sub-cicatricial area in one patient and outside the irradiated area in the other one. They both underwent radical surgery and chemotherapy was performed in one patient.

Discussion

The underlying mechanism for development of RIAS is not well known, but its incidence seems to be increasing. RIAS after partial breast irradiation is very rare and has been reported in two cases so far. As it may be suggested in case 2, it is still a matter of debate if the risk of radiation-induced sarcoma is radiation-dose dependent. Although mastectomy is considered as a standard treatment, choice of treatment should be made according to the patient's specifications.

Conclusion

There are very few studies in the literature that report RIAS after APBI. Present study is the only one reporting two cases after the external 3D technique APBI. Prognosis of RIAS remains poor. Only a careful evaluation in a multidisciplinary context can offer to the patients the best result in terms of local control and survival.

Computed tomography-guided partial-breast brachytherapy using implanted catheters as fiducial markers versus co-registered magnetic resonance imaging

PURPOSE

Partial-breast irradiation (PBI) needs accurate cavity delineation with computed tomography (CT). In perioperative PBI using multicatheter-interstitial brachytherapy (MIB), catheters implanted during surgery were enabled as fiducial markers. Magnetic resonance imaging (MRI) can also assist delineation with CT.

METHODS

Patients receiving MIB-PBI were analyzed. Cavity visualization scores (CVSs) were categorized with CT. With catheter-based delineation (CBD), the relationship between cavity boundaries and catheters were used to contour the tumor bed. Co-registered MRI delineation (CMD) was also performed. The correlation between cavity volume and the excised tissue weight was compared for the two techniques.

RESULTS

The association between CVS and preoperative characteristics in 159 patients showed mammographic breast density (MBD) remained correlated to CVS on multiple regression analyses; CVS = 5.2-0.61 x MBD (p < 0.0001). In 43 patients, the cavity volumes determined with CBD vs CMD were 12.8 ± 6.4 cm³ vs 16.1 ± 12.4 cm³ (p < 0.0001), and their plots with excised weights showed the best fitting lines were 0.29 vs 0.48 (p < 0.0001), respectively. The correlation coefficients for CBD vs CMD were 0.65 vs 0.55 (p = 0.20) in low (CVS 1-3, n = 27) and 0.72 vs 0.58 (p = 0.36) in high visualized cavities (CVS 4-5, n = 16), respectively.

CONCLUSIONS

The use of implanted catheters as fiducial markers was associated with smaller cavities and greater correlations with the excised tissue weights than co-registration with MRI. This might be a useful technique, especially for patients with dense breasts on mammography.

Partial breast irradiation versus whole breast radiotherapy for early breast cancer

BACKGROUND

Breast-conserving therapy for women with breast cancer consists of local excision of the tumour (achieving clear margins) followed by radiotherapy (RT). Most true recurrences occur in the same quadrant as the original tumour. Whole breast radiotherapy (WBRT) may not protect against the development of a new primary cancer developing in other quadrants of the breast. In this Cochrane Review, we investigated the delivery of radiation to a limited volume of the breast around the tumour bed (partial breast irradiation (PBI)) sometimes with a shortened treatment duration (accelerated partial breast irradiation (APBI)).

OBJECTIVES

To determine whether PBI/APBI is equivalent to or better than conventional or hypofractionated WBRT after breast-conserving therapy for early-stage breast cancer.

SEARCH METHODS

On 27 August 2020, we searched the Cochrane Breast Cancer Group Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL and three trial databases. We searched for grey literature: OpenGrey (September 2020), reference lists of articles, conference proceedings and published abstracts, and applied no language restrictions.

SELECTION CRITERIA

Randomised controlled trials (RCTs) without confounding, that evaluated conservative surgery plus PBI/APBI versus conservative surgery plus WBRT. Published and unpublished trials were eligible.

DATA COLLECTION AND ANALYSIS

Two review authors (BH and ML) performed data extraction, used Cochrane's risk of bias tool and resolved any disagreements through discussion, and assessed the certainty of the evidence for main outcomes using GRADE. Main outcomes were local recurrence-free survival, cosmesis, overall survival, toxicity (subcutaneous fibrosis), cause-specific survival, distant metastasis-free survival and subsequent mastectomy. We entered data into Review Manager 5 for analysis.

MAIN RESULTS

We included nine RCTs that enrolled 15,187 women who had invasive breast cancer or ductal carcinoma in-situ (6.3%) with T1-2N0-1M0 Grade I or II unifocal tumours (less than 2 cm or 3 cm or less) treated with breast-conserving therapy with negative margins. This is the second update of the review and includes two new studies and 4432 more participants. Local recurrence-free survival is probably slightly reduced (by 3/1000, 95% CI 6 fewer to 0 fewer) with the use of PBI/APBI compared to WBRT (hazard ratio (HR) 1.21, 95% confidence interval (CI) 1.03 to 1.42; 8 studies, 13,168 participants; moderate-certainty evidence). Cosmesis (physician/nurse-reported) is probably worse (by 63/1000, 95% CI 35 more to 92 more) with the use of PBI/APBI (odds ratio (OR) 1.57, 95% CI 1.31 to 1.87; 6 studies, 3652 participants; moderate-certainty evidence). Overall survival is similar (0/1000 fewer, 95% CI 6 fewer to 6 more) with PBI/APBI and WBRT (HR 0.99, 95% CI 0.88 to 1.12; 8 studies, 13,175 participants; high-certainty evidence). Late radiation toxicity (subcutaneous fibrosis) is probably increased (by 14/1000 more, 95% CI 102 more to 188 more) with PBI/APBI (OR 5.07, 95% CI 3.81 to 6.74; 2 studies, 3011 participants; moderate-certainty evidence). The use of PBI/APBI probably makes little difference (1/1000 less, 95% CI 6 fewer to 3 more) to cause-specific survival (HR 1.06, 95% CI 0.83 to 1.36; 7 studies, 9865 participants; moderate-certainty evidence). We found the use of PBI/APBI compared with WBRT probably makes little or no difference (1/1000 fewer (95% CI 4 fewer to 6 more)) to distant metastasis-free survival (HR 0.95, 95% CI 0.80 to 1.13; 7 studies, 11,033 participants; moderate-certainty evidence). We found the use of PBI/APBI in comparison with WBRT makes little or no difference (2/1000 fewer, 95% CI 20 fewer to 20 more) to mastectomy rates (OR 0.98, 95% CI 0.78 to 1.23; 3 studies, 3740 participants, high-certainty evidence).

AUTHORS' CONCLUSIONS

It appeared that local recurrence-free survival is probably worse with PBI/APBI; however, the difference was small and nearly all women remain free of local recurrence. Overall survival is similar with PBI/APBI and WBRT, and we found little to no difference in other oncological outcomes. Some late effects (subcutaneous fibrosis) may be worse with PBI/APBI and its use is probably associated with worse cosmetic outcomes. The limitations of the data currently available mean that we cannot make definitive conclusions about the efficacy and safety or ways to deliver PBI/APBI. We await completion of ongoing trials.

Health-related quality of life of early-stage breast cancer patients after different radiotherapy regimens

Purpose

To evaluate and compare health-related quality of life (HRQL) of women with early-stage breast cancer (BC) treated with different radiotherapy (RT) regimens.

Methods

Data were collected from five prospective cohorts of BC patients treated with breast-conserving surgery and different RT regimens: intraoperative RT (IORT, 1 × 23.3 Gy; n = 267), external beam accelerated partial breast irradiation (EB-APBI, 10 × 3.85 Gy; n = 206), hypofractionated whole breast irradiation(hypo-WBI, 16 × 2.67 Gy; n = 375), hypo-WBI + boost(hypo-WBI-B, 21–26 × 2.67 Gy; n = 189), and simultaneous WBI + boost(WBI-B, 28 × 2.3 Gy; n = 475).

Women ≥ 60 years with invasive/in situ carcinoma ≤ 30 mm, cN0 and pN0-1a were included. Validated EORTC QLQ-C30/BR23 questionnaires were used to asses HRQL. Multivariable linear regression models adjusted for confounding (age, comorbidity, pT, locoregional treatment, systemic therapy) were used to compare the impact of the RT regimens on HRQL at 12 and 24 months. Differences in HRQL over time (3–24 months) were evaluated using linear mixed models.

Results

There were no significant differences in HRQL at 12 months between groups except for breast symptoms which were better after IORT and EB-APBI compared to hypo-WBI at 12 months (p < 0.001). Over time, breast symptoms, fatigue, global health status and role functioning were significantly better after IORT and EB-APBI than hypo-WBI. At 24 months, HRQL was comparable in all groups.

Conclusion

In women with early-stage breast cancer, the radiotherapy regimen did not substantially influence long-term HRQL with the exception of breast symptoms. Breast symptoms are more common after WBI than after IORT or EB-APBI and improve slowly until no significant difference remains at 2 years posttreatment.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10549-021-06314-4.

Comparing Local and Systemic Control between Partial- and Whole-Breast Radiotherapy in Low-Risk Breast Cancer-A Meta-Analysis of Randomized Trials

PURPOSE/OBJECTIVE

The standard treatment for localized low-risk breast cancer is breast-conserving surgery, followed by adjuvant radiotherapy and appropriate systemic therapy. As the majority of local recurrences occur at the site of the primary tumor, numerous trials have investigated partial-breast irradiation (PBI) instead of whole-breast treatment (WBI) using a multitude of irradiation techniques and fractionation regimens. This meta-analysis addresses the impact on disease-specific endpoints, such as local and regional control, as well as disease-free survival of PBI compared to that of WBI in published randomized trials.

MATERIAL AND METHODS

We conducted a systematic literature review and searched for randomized trials comparing WBI and PBI in early-stage breast cancer with publication dates after 2009. The meta-analysis was based on the published event rates and the effect sizes for available oncological endpoints of at least two trials reporting on them. We evaluated in-breast tumor recurrences (IBTR), local recurrences at the primary site and elsewhere in the ipsilateral breast, regional recurrences (RR), distant metastasis-free interval (DMFI), disease-free survival (DFS), contralateral breast cancer (CBC), and second primary cancer (SPC). Furthermore, we aimed to assess the impact of different PBI techniques and subgroups on IBTR. We performed all statistical analyses using the inverse variance heterogeneity model to pool effect sizes.

RESULTS

For the intended meta-analysis, we identified 13 trials (overall 15,561 patients) randomizing between PBI and WBI. IBTR was significantly higher after PBI (OR = 1.66; CI-95%: 1.07-2.58; p = 0.024) with an absolute difference of 1.35%. We detected significant heterogeneity in the analysis of the PBI technique with intraoperative radiotherapy resulting in higher local relapse rates (OR = 3.67; CI-95%: 2.28-5.90; p < 0.001). Other PBI techniques did not show differences to WBI in IBTR. Both strategies were equally effective at the primary tumor site, but PBI resulted in statistically more IBTRs elsewhere in the ipsilateral breast. IBTRs after WBI were more likely to be located at the primary tumor bed, whereas they appeared equally distributed within the breast after PBI. RR was also more frequent after PBI (OR = 1.75; CI-95%: 1.07-2.88; p < 0.001), yet we did not detect any differences in DMFI (OR = 1.08; CI-95%: 0.89-1.30; p = 0.475). DFS was significantly longer in patients treated with WBI (OR = 1.14; CI-95%: 1.02-1.27; p = 0.003). CBC and SPC were not different in the test groups (OR = 0.81; CI-95%: 0.65-1.01; p = 0.067 and OR = 1.09; CI-95%: 0.85-1.40; p = 0.481, respectively).

CONCLUSION

Limiting the target volume to partial-breast radiotherapy appears to be appropriate when selecting patients with a low risk for local and regional recurrences and using a suitable technique.

Hypofractionated breast irradiation: a multidisciplinary review of the Senonetwork study group

The multidisciplinary management represents a crucial part of the care for cancer patients, resulting in better clinical and process outcomes, with evidence of improved survival among different cancer primary sites, including breast. According with international recommendations established by the European Society of Breast Cancer Specialists (EUSOMA), all breast-cancer patients have to be evaluated by a multidisciplinary team including radiologist, pathologist, surgeon, medical oncologist and radiation oncologist. Thus, variations in clinical practice of each specialty should be discussed and shared with all team members to guarantee a fruitful cooperation among the involved specialists. During the last decades, radiation treatment was deeply changed by the evidence-based adoption of hypofractionated radiotherapy (HFRT) as standard of treatment in patients with early-stage breast cancer undergoing conservative surgery. Moreover, mature randomized data have showed that partial breast irradiation (PBI) is an effective and safe alternative to whole breast irradiation in selected patients with low-risk early-stage breast cancer. Based on this background, we reviewed indications and critical issues of HFRT and PBI analyzing impact of their adoption from a multidisciplinary perspective.

Predicting adherence of dose-volume constraints for personalized partial-breast irradiation technique

PURPOSE

Multicatheter interstitial brachytherapy (MIB) and external-beam (EB) radiotherapy are established partial-breast irradiation (PBI) techniques. Although EB-PBI is widely available, it requires extra irradiated margins for target uncertainties. We examined the impact of EB-PBI on dose-volume constraints as compared to MIB-PBI.

METHODS AND MATERIALS

Among 653 patients receiving MIB-PBI between October 2008 and April 2020, consequent 159 patients after September 2018 were examined. Clinical target volume (CTV) included the lumpectomy cavity plus 1.0 cm. Planning target volume (PTV) for EB-PBI was defined as CTV with 1.0-cm expansion. Because the ratio of PTV to breast volume (RPB) was related to cosmesis, <25% of RPB was defined as suitable for the ipsilateral breast constraints. Preoperative breast size was classified as very small (<350 cm³), small (350-699 cm³), and medium or large (≥700 cm³). According to each category, the dose-volume constraints of the organs at risk were compared between the two PBI techniques.

RESULTS

Patients including 84 very small, 59 small, and 16 moderate to large breasts were examined. Although RPB was suitable in all patients receiving MIB-PBI, it was achieved in 74 patients (46.5%) receiving EB-PBI (p < 0.0001). The suitable RPB in patients with very small, small, and moderate to large breast was 32.1%, 55.9%, and 100%, respectively (p < 0.0001). Normal-tissue constraints for the other organs could be satisfied in patients with moderate to large breasts.

CONCLUSION

Although EB-PBI may be an appropriate option for patients with moderate to large breasts, MIB-PBI could still be a crucial technique, especially for patients with small breasts.