Radiation techniques and toxicities for locally advanced breast cancer

Diagnosis and treatment status of inoperable locally advanced breast cancer and the application value of inorganic nanomaterials

Locally advanced breast cancer (LABC) is a heterogeneous group of breast cancer that accounts for 10-30% of breast cancer cases. Despite the ongoing development of current treatment methods, LABC remains a severe and complex public health concern around the world, thus prompting the urgent requirement for innovative diagnosis and treatment strategies. The primary treatment challenges are inoperable clinical status and ineffective local control methods. With the rapid advancement of nanotechnology, inorganic nanoparticles (INPs) exhibit a potential application prospect in diagnosing and treating breast cancer. Due to the unique inherent characteristics of INPs, different functions can be performed via appropriate modifications and constructions, thus making them suitable for different imaging technology strategies and treatment schemes. INPs can improve the efficacy of conventional local radiotherapy treatment. In the face of inoperable LABC, INPs have proposed new local therapeutic methods and fostered the evolution of novel strategies such as photothermal and photodynamic therapy, magnetothermal therapy, sonodynamic therapy, and multifunctional inorganic nanoplatform. This article reviews the advances of INPs in local accurate imaging and breast cancer treatment and offers insights to overcome the existing clinical difficulties in LABC management.

Elevated Levels of Serum Biomarkers Associated with Damage to the CNS Neurons and Endothelial Cells Are Linked with Changes in Brain Connectivity in Breast Cancer Patients with Vestibulo-Atactic Syndrome

Vestibulo-atactic syndrome (VAS), which represents a combination of motor and vestibular disorders, can be manifested as a clinical complication of breast cancer treatment and has a significant impact on patients' quality of life. The identification of novel potential biomarkers that might help to predict the onset of VAS and its progression could improve the management of this group of patients. In the current study, the levels of intercellular cell adhesion molecule 1 (ICAM-1), platelet/endothelial cell adhesion molecule 1 (PECAM-1), NSE (neuron-specific enolase), and the antibodies recognizing NR-2 subunit of NMDA receptor (NR-2-ab) were measured in the blood serum of BC survivor patients with vestibulo-atactic syndrome (VAS) and associated with the brain connectome data obtained via functional magnetic resonance imaging (fMRI) studies. A total of 21 patients were registered in this open, single-center trial and compared to age-matched healthy female volunteers (control group) (n = 17). BC patients with VAS demonstrated higher serum levels of ICAM-1, PECAM-1, and NSE and a lower value of NR-2-ab, with values of 654.7 ± 184.8, 115.3 ± 37.03, 49.9 ± 103.9, and 0.5 ± 0.3 pg/mL, respectively, as compared to the healthy volunteers, with 230.2 ± 44.8, 62.8 ± 15.6, 15.5 ± 6.4, and 1.4 ± 0.7 pg/mL. According to the fMRI data (employing seed-to-voxel and ROI-to-ROI methods), in BC patients with VAS, significant changes were detected in the functional connectivity in the areas involved in the regulation of postural-tonic reflexes, the coordination of movements, and the regulation of balance. In conclusion, the detected elevated levels of serum biomarkers may reveal damage to the CNS neurons and endothelial cells that is, in turn, associated with the change in the brain connectivity in this group of patients.

Benefit of Deep Inspiratory Breath Hold for Right Breast Cancer When Regional Lymph Nodes Are Irradiated

BACKGROUND

Although deep inspiratory breath-hold (DIBH) is routinely used for left-sided breast cancers, its benefits for right-sided breast cancer (rBC) have yet to be established. We compared free-breathing (FB) and DIBH treatment plans for a cohort of rBC undergoing regional nodal irradiation (RNI) to determine its potential benefits.

METHODS AND MATERIALS

rBC patients considered for RNI (internal mammary nodal chains, supraclavicular field, with or without axilla) from October 2017 to May 2020 were included in this analysis. For each patient, FB versus DIBH plans were generated and dose volume histograms evaluated the following parameters: mean lung dose, ipsilateral lung V₂₀/V₅ (volumes of lung receiving 20 Gy and 5 Gy, respectively); mean heart dose and heart V₅ (volumes of heart receiving 5 Gy); liver V_{20 absolute} /V_{30 absolute} (absolute volume of liver receiving 20 Gy and 30 Gy, respectively), liver D_max, and total liver volume irradiated (TVI_liver). The dosimetric parameters were compared using Wilcoxon signed-rank testing.

RESULTS

Fifty-four patients were eligible for analysis, comparing 108 FB and DIBH plans. DIBH significantly decreased all lung and liver parameters: mean lung dose (19.7 Gy-16.2 Gy, P < .001), lung V₂₀ (40.7%-31.7%, P < .001), lung V₅ (61.2%-54.5%, P < .001), TVI_liver (1446 cc vs 1264 cc; P = .006) liver D_max (50.2 Gy vs 48.9 Gy; P = .023), liver V₂₀ (78.8-23.9 cc, P < .001), and liver V₃₀ (58.1-14.6 cc, P < .001) compared with FB. DIBH use did not significantly improve heart parameters, although the V_5Heart trended on significance (1.25-0.6, P = .067).

CONCLUSIONS

This is the largest cohort to date analyzing DIBH for RNI-rBC. Our findings demonstrate significant improvement in all lung and liver parameters with DIBH, supporting its routine consideration for rBC patients undergoing comprehensive RNI.

Standard Tangential Radiation Fields Do Not Provide Incidental Coverage to the Internal Mammary Nodes

PURPOSE

The purpose of the study was to evaluate the incidental dose delivered to the internal mammary nodes (IMNs) in patients treated with tangential 3-dimensional conformal radiation therapy and to identify potential parameters that may affect the IMN mean dose.

METHODS AND MATERIALS

The study cohort consisted of 362 consecutively treated patients with breast cancer in our center between January 2015 and July 2017 who had received adjuvant whole-breast radiation therapy or postmastectomy radiation with or without a supraclavicular ± axillary field and without intentional inclusion of the IMN chain. The clinical target volume (CTV) for the IMNs was contoured per the Radiation Therapy Oncology Group 3509/3510 protocol and was then divided into 3 subregions: upper, mid, and lower thirds. The planning target volume for the IMNs was generated by adding 5 mm to the CTV. The primary endpoint was to assess the V40 (volume receiving 40 Gy) to the IMN planning target volume and its potential influencing parameters using a linear regression model.

RESULTS

The mean (±standard deviation) dose to the CTV IMN chain was 36% ± 28.7%. The Kruskal-Wallis test demonstrated significant differences in the median dose delivered to each level: upper third (7.2%), mid third (21.5%), and lower third (41.7%) (P < .001). The mean V40 IMN planning target volume was 14.2% (standard deviation, 18.7%). Presternal fat thickness (regression coefficient [RC] = -16.4; P < .001), postmastectomy radiation (RC = 24; P < .001), reconstruction after mastectomy (RC = -22.4; P < .001), and the addition of a supraclavicular field (RC = 8.8; P = .03) were all significantly associated with IMN mean dose.

CONCLUSIONS

For patients receiving standard breast/chest wall tangential radiation fields, the IMN chain is not incidentally covered with therapeutic doses in the vast majority of cases. Therefore, if regional nodal radiation is intended to include the IMNs, contouring and careful plan review are necessary to ensure adequate therapeutic coverage.

The effect of lateral pectoral nerve sparing technique and radiotherapy on the pectoralis major muscle applied with modified radical mastectomy

BACKGROUND/OBJECTIVE

The aim of this study was to evaluate with electromyography (EMG) the effect of lateral pectoral nerve sparing technique (LPNST) and radiotherapy (RT) on the lateral pectoral nerve (LPN) in patients applied with modified radical mastectomy (MRM).

METHODS

The study included 66 patients who underwent MRM surgery. The patients were separated into 2 groups as those applied with LPNST and those who underwent standard surgery (Control group). Within these 2 groups, patients were again separated as those who received or did not receive RT. The EMG evaluations were made by a neurology specialist blinded to the patient groups.

RESULTS

The mean age of the patients was 53.3 ± 10.6 years. Standard surgery was applied to 33 (50%) patients and LPNST to 33 (50%) patients, RT was applied to 32 (48.5%) patients and not to 34 (51.5%) patients. In the EMG evaluation, latency was 2.1 ms (1.4-3.2) in the LPNST and 3.7 ms (1.9-12.4) in the control (p <0.001) and amplitude values were 9650 mV (3120-36900) in the LPNST and 4780 mV (510-12.4) in the control (p <0.001). The latency values in the Control receiving and not receiving RT were 4.0 ms (1.9-12.4) and 2.6 ms (1.9-6.2) respectively (p <0.05). The latency values of the patients receiving and not receiving RT in the LPNST were 2.2 ms (1.8-3.2) and 2.0 ms (1.4-2.4) respectively (p <0.05). In the Control and LPNST Group, no significant difference was determined between receiving and not receiving RT groups in respect of amplitude values (p >0.05).

CONCLUSION

The results of this study demonstrated that electromyographically the latency and amplitude values were better protected in the LPNST group. It was also seen that RT increased the formation of nerve damage in both groups.

Advancements and Personalization of Breast Cancer Treatment Strategies in Radiation Therapy

Significant technologic advances in radiation treatment delivery now allow for more personalized delivery considerations which incorporate individual patient characteristics (such as tumor location and patient anatomy) and more precise delivery in the breast conservation or post-mastectomy setting. The combined advancements with other treatment modalities (i.e., systemic therapy, surgical management) have had direct effects on local-regional management and outcomes such that currently, local-regional relapses after definitive treatment for localized disease are now rarely experienced. Recent advances in the radiation therapy field have come from careful patient selection for a variety of three-dimensional treatment delivery techniques and alternatives to conventional tangential radiation. These advances have been demonstrated to diminished acute/long-term toxicity, minimized dose to surrounding normal tissue structures such as the heart and lung, and ultimately result in an improvement in the therapeutic ratio for radiation treatment. This chapter discusses recent radiation innovations and appropriate patient selection for their application, for a more personalized approach to radiation therapy for breast cancer patients.

TGF-β1 Is Present at High Levels in Wound Fluid from Breast Cancer Patients Immediately Post-Surgery, and Is Not Increased by Intraoperative Radiation Therapy (IORT)

In patients with low-risk breast cancer, intraoperative radiotherapy (IORT) during breast-conserving surgery is a novel and convenient treatment option for delivering a single high dose of irradiation directly to the tumour bed. However, edema and fibrosis can develop after surgery and radiotherapy, which can subsequently impair quality of life. TGF- β is a strong inducer of the extracellular matrix component hyaluronan (HA). TGF-β expression and HA metabolism can be modulated by irradiation experimentally, and are involved in edema and fibrosis. We therefore hypothesized that IORT may regulate these factors.Wound fluid (WF) draining from breast lumpectomy sites was collected and levels of TGF-β1 and HA were determined by ELISA. Proliferation and marker expression was analyzed in primary lymphatic endothelial cells (LECs) treated with recombinant TGF-β or WF. Our results show that IORT does not change TGF-β1 or HA levels in wound fluid draining from breast lumpectomy sites, and does not lead to accumulation of sHA oligosaccharides. Nevertheless, concentrations of TGF-β1 were high in WF from patients regardless of IORT, at concentrations well above those associated with fibrosis and the suppression of LEC identity. Consistently, we found that TGF-β in WF is active and inhibits LEC proliferation. Furthermore, all three TGF-β isoforms inhibited LEC proliferation and suppressed LEC marker expression at pathophysiologically relevant concentrations.

Given that TGF-β contributes to edema and plays a role in the regulation of LEC identity, we suggest that inhibition of TGF-β directly after surgery might prevent the development of side effects such as edema and fibrosis.

Influence of Individualized Stabilization on the Consistency of Supraclavicular Fossa Positioning in Breast Radiation Therapy: A Retrospective Study

INTRODUCTION

The accurate stabilization of breast patients who are also undergoing supraclavicular fossa treatment is essential and can be challenging. Discrepancy in setup error for these patients often lies with the position of the clavicle in relationship with other anatomic structures. This study was performed to assess how individualized stabilization can improve patient's stability and reproducibility.

METHODS

Thirty patients stabilized with an individualized vacfix located on a Civco wing board (Civco Medical Solutions, Kalona, IA) were compared with 30 patients stabilized in the traditional manner on a Civco breast board (Civco Medical Solutions). Each of these patients underwent daily imaging using the Varian Clinac iX On-board Imaging System (Varian Medical Systems, Palo Alto, CA), and image mismatch data for each session were collected. Additionally, the relationship between the clavicle and vertebrae was assessed for each stabilization solution on a daily basis. Statistical analysis of this data was then performed using a mixed effects approach to take account of data grouping by patient specifically for the displacement error in each direction.

RESULTS

The use of an individualized vacfix decreased the overall systematic and random setup errors and displayed a reduction in the standard deviation of setup error. Patients positioned using breast board stabilization with the clavicle as the match method were exposed in the longitudinal direction to a systematic error of a 95% confidence interval (CI) of 2.6-4.5 mm and a random error of a 95% CI of 2.7-3.2 mm. This was significantly reduced for vacfix stabilization with a systematic error of a 95% CI of 1.2-2.3 mm and a random error of a 95% CI of 1.8-2.3 mm. These data amount to a reduction of the systematic error by 40% (P = .02) and a random error by 25% (P = .003) when using the vacfix method compared with the breast board. The data displaying the relationship between the clavicle and other anatomy within the treatment volume appear to be more consistent with the individualized vacfix approach.

CONCLUSIONS

Reproducible and consistent stabilization for the breast/supraclavicular fossa technique is vital in terms of ensuring accurate patient position. Analysis of the setup error for clavicle and spinous process matching strongly indicates a reduction in both the systematic and random setup error achieved by the vacfix. This illustrates the increased stability and reproducibility of patient positioning when an individualized vacfix is used.

Is Ki-67 expression prognostic for local relapse in early-stage breast cancer patients treated with breast conservation therapy (BCT)?

PURPOSE

Ki-67 is a human nuclear protein whose expression is strongly up-regulated in proliferating cells and can be used to determine the growth fraction in clonal cell populations. Although there are some data to suggest that Ki-67 overexpression may be prognostic for endpoints such as survival or postmastectomy recurrence, further elucidation of its prognostic significance is warranted. Specifically after breast conservation therapy (BCT) (defined in this setting as breast-conserving surgery and adjuvant radiation therapy), whether Ki-67 predicts for locoregional recurrence has not been investigated. The purpose of this study was to assess Ki-67 expression in a cohort of early-stage breast cancer patients to determine whether a significant independent association between Ki-67 and locoregional relapse exists.

METHODS AND MATERIALS

Ki-67 staining was conducted on a tissue microarray of 438 patients previously treated with BCT, and expression was analyzed with clinicopathologic features and outcomes from our database.

RESULTS

Ki-67 expression was more prevalent in black patients (37% of black patients vs 17% of white patients, P<.01), younger patients (27% of patients aged ≤50 years vs 15% of patients aged >50 years, P<.01), estrogen receptor (ER)-negative tumors (25% of ER-negative tumors vs 17% of ER-positive tumors, P=.04), human epidermal growth factor receptor 2 (HER2)/neu-positive tumors (35% of HER2-positive tumors vs 18% of HER2-negative tumors, P=.01), and larger tumors (26% of T2 tumors vs 16% of T1 tumors, P=.03). On univariate/multivariate analysis, Ki-67 did not predict for overall survival (74.4% vs 72.6%), cause-specific survival (82.9% vs 82.1%), local relapse-free survival (83.6% vs 88.5%), distant metastasis-free survival (76.1% vs 81.4%), recurrence-free survival (65.5% vs 74.6%), and locoregional recurrence-free survival (81.6% vs 84.7%): P>.05 for all.

CONCLUSIONS

Ki-67 appears to be a surrogate marker for aggressive disease and significantly correlates with known prognostic features such as age, race, hormone receptor status, and HER2 status but independently does not predict for locoregional outcomes after BCT when these other prognostic clinicopathologic features are taken into consideration. The independent associations of Ki-67 with race and age appear to be novel to our study.

UHRF1 confers radioresistance to human breast cancer cells

PURPOSE

To investigate the effect of ubiquitin-like with plant homeodomain (PHD) and ring finger domains 1 (UHRF1) overexpression on radiosensitivity to X-rays in human breast cancer MDA-MB-231 cells.

MATERIALS AND METHODS

Cell survival was determined by colony formation assay; cell cycle distribution was measured by flow cytometry; apoptosis was evaluated by DNA fragmentation assay and Annexin V apoptosis detection kit; protein expression was analysed by Western blot assay; chromosome aberrations (centric rings and dicentrics) were assayed by conventional chromosome analysis.

RESULTS

A significant decrease of radiosensitivity to X-rays was observed in MDA-MB-231 cells transfected with a full-length of human UHRF1 cDNA (MDA-MB-231/UHRF1) compared to the control cells (MDA-MB-231/parental and MDA-MB-231/pcDNA3 [mammalian expression vector]), and the similar results were observed in MDA-MB-468 cells. In contrast, a decreased expression of UHRF1 by a specific UHRF1-small interfering RNA (siRNA) significantly enhanced cell radiosensitivity. The UHRF1-mediated radioresistance was correlated with a G2(Ra)/M arrest, a decreased induction of apoptosis, a down-regulation of the pro-apoptotic protein anti-B cell lymphoma/leukemia 2 (bcl-2) associated X protein (Bax) and a up-regulation of the DNA damage repair proteins Lupus Ku autoantigen protein p70 (Ku-70) and Lupus Ku autoantigen protein p80 (Ku-80). Furthermore, chromosomal aberrations (centric rings and dicentrics) by X-rays were less in MDA-MB-231/UHRF1 than in MDA-MB-231/parental and MDA-MB-231/pcDNA3 control cells.

CONCLUSIONS

These results suggested that UHRF1 may be a new target in the radiotherapy of breast cancer via affecting apoptosis and DNA damage repair.

Tumor senescence and radioresistant tumor-initiating cells (TICs): let sleeping dogs lie!

Preclinical data from cell lines and experimental tumors support the concept that breast cancer-derived tumor-initiating cells (TICs) are relatively resistant to ionizing radiation and chemotherapy. This could be a major determinant of tumor recurrence following treatment. Increased clonogenic survival is observed in CD24^-/low/CD44⁺ TICs derived from mammosphere cultures and is associated with (a) reduced production of reactive oxygen species, (b) attenuated activation of γH2AX and CHK2-p53 DNA damage signaling pathways, (c) reduced propensity for ionizing radiation-induced apoptosis, and (d) altered DNA double-strand or DNA single-strand break repair. However, recent data have shed further light on TIC radioresistance as irradiated TICs are resistant to tumor cell senescence following DNA damage. Taken together, the cumulative data support a model in which DNA damage signaling and repair pathways are altered in TICs and lead to an altered mode of cell death with unique consequences for long-term clonogen survival. The study of TIC senescence lays the foundation for future experiments in isogenic models designed to directly test the capacity for senescence and local control (that is, not solely local regression) and spontaneous metastases following treatment in vivo. The study also supports the targeting of tumor cell senescence pathways to increase TIC clonogen kill if the targeting also maintains the therapeutic ratio.