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

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.

Comparison of partial-breast irradiation and intraoperative radiation to whole-breast irradiation in early-stage breast cancer patients: a Kaplan-Meier-derived patient data meta-analysis

PURPOSE

Partial breast irradiation (PBI) and intraoperative radiation (IORT) represent alternatives to whole breast irradiation (WBI) following breast conserving surgery. However, data is mixed regarding outcomes. We therefore performed a pooled analysis of Kaplan-Meier-derived patient data from randomized trials to evaluate the hypothesis that PBI and IORT have comparable long-term rates of ipsilateral breast tumor recurrence as WBI.

METHODS

In February, 2023, PubMed, EMBASE and Cochrane Central were systematically searched for randomized phase 3 trials of early-stage breast cancer patients undergoing breast-conserving surgery with PBI or IORT as compared to WBI. Time-to-event outcomes of interest included ipsilateral breast tumor recurrence (IBTR), overall survival (OS) and distant disease-free survival (DDFS). Statistical analysis was performed with R Statistical Software.

RESULTS

Eleven randomized trials comprising 15,460 patients were included; 7,675 (49.6%) patients were treated with standard or moderately hypofractionated WBI, 5,413 (35%) with PBI and 2,372 (15.3%) with IORT. Median follow-up was 9 years. PBI demonstrated comparable IBTR risk compared with WBI (HR 1.20; 95% CI 0.95-1.52; p = 0.12) with no differences in OS (HR 1.02; 95% CI 0.90-1.16; p = 0.70) or DDFS (HR 1.15; 95% CI 0.81-1.64; p = 0.43). In contrast, patients treated with IORT had a higher IBTR risk (HR 1.46; 95% CI 1.23-1.72; p < 0.01) compared with WBI with no difference in OS (HR 0.98; 95% CI 0.84-1.14; p = 0.81) or DDFS (HR 0.91; 95% CI 0.76-1.09; p = 0.31).

CONCLUSION

For patients with early-stage breast cancer following breast-conserving surgery, PBI demonstrated no difference in IBTR as compared to WBI while IORT was inferior to WBI with respect to IBTR.

Impact of breath hold on regional nodal irradiation and heart volume in field in left breast cancer adjuvant irradiation

PURPOSE

Compared to the free-breathing technique, adjuvant left breast irradiation after breast-conserving surgery or mastectomy using the breath-hold method significantly reduces the heart mean dose, Left anterior descending artery, and ipsilateral lung doses. Movement with deep inspiration may also reduce heart volume in the field and regional node doses.

MATERIALS AND METHODS

Pre-radiotherapy planning CT was performed in the free-breathing, and breath-hold techniques using RPM, demographic information, clinicopathological data, heart volume in the field, heart mean dose, LAD mean dose, and regional nodal doses were calculated in both free breathing and DIBH. Fifty patients with left breast cancer receiving left breast adjuvant radiation were enrolled.

RESULTS

There was no significant difference in axillary LN coverage between the two techniques, except for SCL maximum dose, Axilla I node maximum dose, and Axilla II minimum dose in favor of the breath hold technique. The mean age was 47.54 years, 78% had GII IDC, 66% had positive LVSI results, and 74% of patients had T2. The breath hold strategy resulted in considerably decreased mean heart dose (p = 0.000), LAD dose (p = 0.000), ipsilateral lung mean dose (p = 0.012), and heart volume if the field (p = 0.013). The mean cardiac dosage and the dose of the LAD were significantly correlated (p = 0.000, R = 0.673). Heart volume in the field and heart mean dosage was not significantly correlated (p = 0.285, r = - 0.108).

CONCLUSION

When compared to free breathing scans, DIBH procedures result in considerably reduced dosage to the OAR and no appreciable changes in dose exposure to regional lymph node stations in patients with left-sided breast cancer.

Comparison of adverse events in partial- or whole breast radiotherapy: investigation of cosmesis, toxicities and quality of life in a meta-analysis of randomized trials

PURPOSE/OBJECTIVE

Adjuvant whole breast radiotherapy and systemic therapy are part of the current evidence-based treatment protocols for early breast cancer, after breast-conserving surgery. Numerous randomized trials have investigated the therapeutic effects of partial breast irradiation (PBI) compared to whole breast irradiation (WBI), limiting the treated breast tissue. These trials were designed to achieve equal control of the disease with possible reduction in adverse events, improvements in cosmesis and quality of life (QoL). In this meta-analysis, we aimed to investigate the differences between PBI and WBI in side effects and QoL.

MATERIAL/METHODS

We performed a systematic literature review searching for randomized trials comparing WBI and PBI in early-stage breast cancer with publication dates after 2009. The meta-analysis was performed using the published event rates and the effect-sizes for available acute and late adverse events. Additionally, we evaluated cosmetic outcomes as well as general and breast-specific QoL using the EORTC QLQ-C30 and QLQ-BR23 questionnaires.

RESULTS

Sixteen studies were identified (n = 19,085 patients). PBI was associated with a lower prevalence in any grade 1 + acute toxicity and grade 2 + skin toxicity (OR = 0.12; 95% CI 0.09-0.18; p < 0.001); (OR = 0.16; 95% CI 0.07-0.41; p < 0.001). There was neither a significant difference in late adverse events between the two treatments, nor in any unfavorable cosmetic outcomes, rated by either medical professionals or patients. PBI-technique using EBRT with twice-daily fractionation schedules resulted in worse cosmesis rated by patients (n = 3215; OR = 2.08; 95% CI 1.22-3.54; p = 0.007) compared to WBI. Maximum once-daily EBRT schedules (n = 2071; OR = 0.60; 95% CI 0.45-0.79; p < 0.001) and IORT (p = 0.042) resulted in better cosmetic results grade by medical professionals. Functional- and symptom-based QoL in the C30-scale was not different between PBI and WBI. Breast-specific QoL was superior after PBI in the subdomains of "systemic therapy side effects" as well as "breast-" and "arm symptoms".

CONCLUSION

The analysis of multiple randomized trials demonstrate a superiority of PBI in acute toxicity as well breast-specific quality of life, when compared with WBI. Overall, late toxicities and cosmetic results were similar. PBI-technique with a fractionation of twice-daily schedules resulted in worse cosmesis rated by patients.

Association of HOTAIR gene rs920778 (C > T) and rs4759314 (A > G) polymorphism with breast cancer in Egyptian women

BACKGROUND

Hox transcript antisense RNA (HOTAIR) is considered an oncogene associated with the initiation and progression of many malignancies. Previous studies have examined the connection between HOTAIR SNPs rs4759314 and rs920778 for breast cancer (BC), getting variable results in multiple ethnicities. Therefore, this study was designed to evaluate the connection between these two SNPs and disease vulnerability, clinic-laboratory, and hormonal parameters, featuring status associations with the BC risk in an Egyptian woman sample.

METHODS AND RESULTS

In this case-control study, DNA was taken from the blood of 100 BC patients and 100 unrelated healthy Egyptian females. The characterization of rs4759314 was genotyped using the T-ARMS-PCR method and rs920778 using the SNP-RFLP technique for all participants. The frequency of the rs4759314 A > G variation revealed a statistically significant increase in BC risk with dominant (p = 0.013, OR = 1.592, 95% Cl = 1.105-2.293), co-dominant (p = 0.006, OR = 2.314, 95%Cl = 1.278-4.191) and overdominant (p = 0.002, OR = 2.571, 95% Cl = 1.430-4.624) genetic models. On the other hand, the rs920778 C > T polymorphism was not significantly associated with BC. ER/PR positivity with HER2 negativity was significantly associated with the AA genotype compared to the AG genotype. Otherwise, no significant associations between the two SNPs and clinical stage or hormonal features could be found. In conclusion, the rs4759314 A > G SNP in the HOTAIR gene is strongly associated with BC, which might warrant its determination among affected families for prevention and early treatment.

Real de-escalation or escalation in disguise?

The past two decades have seen an unprecedented trend towards de-escalation of surgical therapy in the setting of early BC, the most prominent examples being the reduction of re-excision rates for close surgical margins after breast-conserving surgery and replacing axillary lymph node dissection by less radical procedures such as sentinel lymph node biopsy (SLNB). Numerous studies confirmed that reducing the extent of surgery in the upfront surgery setting does not impact locoregional recurrences and overall outcome. In the setting of primary systemic treatment, there is an increased use of less invasive staging strategies reaching from SLNB and targeted lymph node biopsy (TLNB) to targeted axillary dissection (TAD). Omission of any axillary surgery in the presence of pathological complete response in the breast is currently being investigated in clinical trials. On the other hand, concerns have been raised that surgical de-escalation might induce an escalation of other treatment modalities such as radiation therapy. Since most trials on surgical de-escalation did not include standardized protocols for adjuvant radiotherapy, it remains unclear, whether the effect of surgical de-escalation was valid in itself or if radiotherapy compensated for the decreased surgical extent. Uncertainties in scientific evidence may therefore lead to escalation of radiotherapy in some settings of surgical de-escalation. Further, the increasing rate of mastectomies including contralateral procedures in patients without genetic risk is alarming. Future studies of locoregional treatment strategies need to include an interdisciplinary approach to integrate de-escalation approaches combining surgery and radiotherapy in a way that promotes optimal quality of life and shared decision-making.

Feasibility Study on the Radiation Dose by Radioactive Magnetic Core-Shell Nanoparticles for Open-Source Brachytherapy

BACKGROUND

Treatment of early-stage breast cancer currently includes surgical removal of the tumor and (partial) breast irradiation of the tumor site performed at fractionated dose. Although highly effective, this treatment is exhaustive for both patient and clinic. In this study, the theoretical potential of an alternative treatment combining thermal ablation with low dose rate (LDR) brachytherapy using radioactive magnetic nanoparticles (RMNPs) containing 103-palladium was researched.

METHODS

The radiation dose characteristics and emission spectra of a single RMNP were calculated, and dose distributions of a commercial brachytherapy seed and an RMNP brachytherapy seed were simulated using Geant4 Monte Carlo toolkit.

RESULTS

It was found that the RMNP seeds deliver a therapeutic dose similar to currently used commercial seed, while the dose distribution shows a spherical fall off compared to the more inhomogeneous dose distribution of the commercial seed. Changes in shell thickness only changed the dose profile between 2 × 10^-4 mm and 3 × 10^-4 mm radial distance to the RMNP, not effecting long-range dose.

CONCLUSION

The dose distribution of the RMNP seed is comparable with current commercial brachytherapy seeds, while anisotropy of the dose distribution is reduced. Because this reduces the dependency of the dose distribution on the orientation of the seed, their surgical placement is easier. This supports the feasibility of the clinical application of the proposed novel treatment modality.

Incidental irradiation of the regional lymph nodes during deep inspiration breath-hold radiation therapy in left-sided breast cancer patients: a dosimetric analysis

Background

Radiotherapy using the deep inspiration breath-hold (DIBH) technique compared with free breathing (FB) can achieve substantial reduction of heart and lung doses in left-sided breast cancer cases. The anatomical organ movement in deep inspiration also cause unintended exposure of locoregional lymph nodes to the irradiation field.

Methods

From 2017–2020, 148 patients with left-sided breast cancer underwent breast conserving surgery (BCS) or mastectomy (ME) with axillary lymph node staging, followed by adjuvant irradiation in DIBH technique. Neoadjuvant or adjuvant systemic therapy was administered depending on hormone receptor and HER2-status.

CT scans in FB and DIBH position with individual coaching and determination of the breathing amplitude during the radiation planning CT were performed for all patients. Intrafractional 3D position monitoring of the patient surface in deep inspiration and gating was performed using Sentinel and Catalyst HD 3D surface scanning systems (C-RAD, Catalyst, C-RAD AB, Uppsala, Sweden). Three-dimensional treatment planning was performed using standard tangential treatment portals (6 or 18 MV). The delineation of ipsilateral locoregional lymph nodes was done on the FB and the DIBH CT-scan according to the RTOG recommendations.

Results

The mean doses (D_mean) in axillary lymph node (AL) level I, II and III in DIBH were 32.28 Gy (range 2.87–51.7), 20.1 Gy (range 0.44–53.84) and 3.84 Gy (range 0.25–39.23) vs. 34.93 Gy (range 10.52–50.40), 16.40 Gy (range 0.38–52.40) and 3.06 Gy (range 0.21–40.48) in FB (p < 0.0001). Accordingly, in DIBH the D_mean for AL level I were reduced by 7.59%, whereas for AL level II and III increased by 22.56% and 25.49%, respectively.

The D_mean for the supraclavicular lymph nodes (SC) in DIBH was 0.82 Gy (range 0.23–4.11), as compared to 0.84 Gy (range 0.22–10.80) with FB (p = 0.002). This results in a mean dose reduction of 2.38% in DIBH.

The D_mean for internal mammary lymph nodes (IM) was 12.77 Gy (range 1.45–39.09) in DIBH vs. 11.17 Gy (range 1.34–44.24) in FB (p = 0.005). This yields a mean dose increase of 14.32% in DIBH.

Conclusions

The DIBH technique may result in changes in the incidental dose exposure of regional lymph node areas.

Implantable Bioresponsive Hydrogel Prevents Local Recurrence of Breast Cancer by Enhancing Radiosensitivity

Breast cancer is one of the most common types of cancer. Patients are often concerned about regional recurrence after breast cancer surgery. Radiotherapy plays a vital role in reducing recurrence and prolonging the survival of patients undergoing breast-conserving surgery and high-risk mastectomy. However, 8–15% of patients still have disease progression due to radiation resistance. Therefore, new strategies for combination radiotherapy sensitization must be investigated. In this study, an implantable drug loading system, sunitinib nanoparticles @ matrix metalloproteinases -response hydrogel (NSMRH), uses enzyme-sensitive hydrogel as a carrier to load sunitinib nanoparticles, was identified. The releasing profile demonstrated that sunitinib nanoparticles may be continuously released from the hydrogels. Functional experiments revealed that, when paired with NSMRH, radiation may significantly inhibit tumor cell proliferation, migration, and invasion in vitro. Further animal experiments showed that NSMRH combined with radiotherapy could more effectively control the recurrence of subcutaneous xenograft tumors, prolong the survival time, and have no obvious toxicity in nude mice. Finally, by studying the molecular mechanism of NSMRH, it was hypothesized that in breast cancer cells, NSMRH cooperated with sensitized radiotherapy, mainly due to significantly blocking the G2/M phase, reducing the DNA repair efficiency, inhibiting tumor angiogenesis, promoting apoptosis, and reversing the abnormal expression of platelet-derived growth factor receptor alpha (PDGFRA) after radiotherapy. These findings suggest that NSMRH’s radiation sensitization and anti-tumor activity may aid in the development of a novel method in future clinical applications.

Implementation of accelerated partial breast irradiation at the Oncology Institute of Vojvodina

Introduction. Early breast cancer is usually treated with breast conserving surgery followed by radiation treatment. Whole breast irradiation is standard of care so far, but currently there is an increasement in accelerated partial breast irradiation for selected patients which showed many advantages. The aim of this paper is to present the implementation of the accelerated partial breast irradiation in Oncology Institute of Vojvodina. Case outline. A 54-year-old woman was referred to radiotherapy after breast conserving surgery. After she met all of the inclusion criteria, she underwent accelerated partial breast irradiation with 38.5 Gy in 10 fractions. Active breathing control device was used during the treatment and cone beam computed tomography was performed before each fraction for purpose of target position control. She terminated therapy in good health condition with only adverse effect of mild radiation dermatitis of irradiated area. On the first follow up, she was without any symptom or sign of disease or complication. Conclusion. Accelerated partial breast irradiation is safe and effective. Radiation oncologist should be encouraged to implement this technique.