Associations between adjuvant radiotherapy and different causes of death in a German breast cancer cohort

A nested case-control study on radiation dose-response for cardiac events in breast cancer patients in Germany

Background

Previous studies with the majority of breast cancer (BC) patients treated up to 2000 provided evidence that radiation dose to the heart from radiotherapy (RT) was linearly associated with increasing risk for long-term cardiac disease. RT techniques changed substantially over time. This study aimed to investigate the dose-dependent cardiac risk in German BC patients treated with more contemporary RT.

Methods

In a cohort of 11,982 BC patients diagnosed in 1998–2008, we identified 494 women treated with 3D-conformal RT who subsequently developed a cardiac event. Within a nested case-control approach, these cases were matched to 988 controls. Controls were patients without a cardiac event after RT until the index date of the corresponding case. Separate multivariable conditional logistic regression models were used to assess the association of radiation to the complete heart and to the left anterior heart wall (LAHW) with cardiac events.

Results

Mean dose to the heart for cases with left-sided BC was 4.27 Gy and 1.64 Gy for cases with right-sided BC. For controls, corresponding values were 4.31 Gy and 1.66 Gy, respectively. The odds ratio (OR) per 1 Gy increase in dose to the complete heart was 0.99 (95% confidence interval (CI): 0.94–1.05, P = .72). The OR per 1 Gy increase in LAHW dose was 1.00 (95% CI: 0.98–1.01, P = .68).

Conclusions

Contrary to previous studies, our study provided no evidence that radiation dose to the heart from 3D-conformal RT for BC patients treated between 1998 and 2008 was associated with risk of cardiac events.

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Dose-response analysis on cardiac late effects in irradiated breast cancer patients.

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Nested case-control study with individual retrospective heart dosimetry.

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Included 494 cases and 988 controls treated in 1998–2008 in Germany.

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No association for cardiac late effects of 3D-conformal radiotherapy observed.

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No association for the complete heart and left anterior heart wall observed.

Association Between Radiotherapy and Death From Cardiovascular Disease Among Patients With Cancer: A Large Population‐Based Cohort Study

Background

This study aimed to investigate the association between radiotherapy for cancer and cardiovascular disease (CVD) deaths and evaluate the relative risk for CVD deaths in the general population and among patients with cancer treated with radiotherapy.

Methods and Results

The statistics of cancers from 16 sites were extracted from the Surveillance, Epidemiology, and End Results database and evaluated. Multivariable Cox proportional hazards regression analysis was used to analyze the association between radiotherapy and cardiovascular‐specific survival. The standardized mortality ratio for CVD deaths was estimated by comparing the observed deaths of patients with cancer treated with radiotherapy to the expected deaths of the general population. Of the 2 214 944 patients identified from the database, 292 102 (13.19%) died from CVD. Multivariable Cox proportional hazards regression analyses demonstrated that radiotherapy was an independent risk factor for cardiovascular‐specific survival among patients with lung and bronchus, cervix uteri, corpus uteri, and urinary bladder cancers. The long‐term cardiovascular‐specific survival of patients with cancer who underwent radiotherapy was significantly lower than that of patients who did not undergo radiotherapy. The incidence of CVD deaths among patients with lung and bronchus, cervix uteri, corpus uteri, and urinary bladder cancers who underwent radiotherapy was higher than that among the general population. Standardized mortality ratio significantly decreased with increasing age at cancer diagnosis, gradually decreased within 10 years of diagnosis and increased after 10 years of diagnosis.

Conclusions

Radiotherapy is associated with worse cardiovascular‐specific survival in patients with lung and bronchus, cervix uteri, corpus uteri, and urinary bladder cancers. Long‐term surveillance of cardiovascular conditions should be performed after radiotherapy.

Cardiac late effects after modern 3D-conformal radiotherapy in breast cancer patients: a retrospective cohort study in Germany (ESCaRa)

Purpose

Radiotherapy (RT) was identified as a risk factor for long-term cardiac effects in breast cancer patients treated until the 1990s. However, modern techniques reduce radiation exposure of the heart, but some exposure remains unavoidable. In a retrospective cohort study, we investigated cardiac mortality and morbidity of breast cancer survivors treated with recent RT in Germany.

Methods

A total of 11,982 breast cancer patients treated between 1998 and 2008 were included. A mortality follow-up was conducted until 06/2018. In order to assess cardiac morbidity occurring after breast cancer treatment, a questionnaire was sent out in 2014 and 2019. The effect of breast cancer laterality on cardiac mortality and morbidity was investigated as a proxy for radiation exposure. We used Cox Proportional Hazards regression analysis, taking potential confounders into account.

Results

After a median follow-up time of 11.1 years, there was no significant association of tumor laterality with cardiac mortality in irradiated patients (hazard ratio (HR) for left-sided versus right-sided tumor 1.09; 95% confidence interval (CI) 0.85–1.41). Furthermore, tumor laterality was not identified as a significant risk factor for cardiac morbidity (HR = 1.05; 95%CI 0.88–1.25).

Conclusions

Even though RT for left-sided breast cancer on average incurs higher radiation dose to the heart than RT for right-sided tumors, we found no evidence that laterality is a strong risk factor for cardiac disease after contemporary RT. However, larger sample sizes, longer follow-up, detailed information on individual risk factors and heart dose are needed to assess clinically manifest late effects of current cancer therapy.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10549-021-06412-3.

Breast Radiation and the Heart: Cardiac Toxicity and Cardiac Avoidance

The purpose of this invited review is to discuss the most recent and relevant outcome studies assessing the risk of late cardiac toxicity in women treated with radiotherapy for breast cancer and to describe the evidence-based technical factors associated with late cardiac toxicity. This review will also discuss the common radiation techniques for reducing radiation dose to the heart, which will lead to better outcomes and lower rates of late toxicity that can cause morbidity and mortality in women who have been cured of their breast cancer.

Aromatase inhibitors and risk of cardiovascular events in breast cancer patients: a systematic review and meta-analysis

BACKGROUND

Cardiovascular events (CVEs) was considered as one of the primary cause to reduce the quality of life in breast cancer patients with aromatase inhibitors (AIs) treatment, which has not been sufficiently addressed. The aim of this study was to assess the correlation between risk of CVEs and AIs in patients with breast cancer.

METHODS

Included studies were obtained from the databases of Embase, Pubmed, Cochrane Library, Clinical Trials.gov, and reference lists. The main outcome measures were overall incidence, odds ratios (ORs), and 95% confidence intervals (CIs). Furthermore, the association and the risk differences among different tumor types, AIs,ages,or treatment regimens were conducted. Fixed-effect or random-effect models were applied in the statistical analyses according to the heterogeneity. Our analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement.

RESULTS

Seventeen studies, which included 44,411 subjects, were included in our analyses. The overall incidence of CVEs in AIs group was 13.02% (95% CI: 8.15-20.17%) and almost all of the high-grade CVEs occurred in patients treated with AIs. The pooled ORs of CVEs was 0.9940 (95% CI: 0.8545-1.1562). Under sub-group analysis, the incidence of CVEs related to exemestane was higher than that of controls (OR = 1.1564, 95% CI: 1.0656-1.2549), but no statistical differences in risk of CVEs were found in other sub-group analysis. No evidence of publication bias was found for incidence of CVEs in our meta-analysis by a funnel plot.

CONCLUSIONS

These results suggest that patients with breast cancer treated with AIs do not have a significant risk of developing CVEs in comparison with the controls, and exemestane might not be considered as the alternative AI to the breast cancer patients from the perspective of CVEs. Further studies are recommended to investigate this association and the risk differences among different tumor types, AIs or treatment regimens.

Effects of radioactive 125I on apoptosis of HGC-27 gastric cancer cells

Effects of radioactive ¹²⁵I particles at different doses on apoptosis of HGC-27 gastric cancer cells were investigated. HGC-27 gastric cancer cell suspension was used to establish a tumor-bearing mouse model. The model was reared for approximately 3 weeks and then divided into the control group (implanted with blank particles), the low dose group (implanted with 1.48×10^-7 Bq ¹²⁵I particles), the medium dose group (implanted with 2.22×10^-7 Bq ¹²⁵I particles) and the high dose group (implanted with 2.96×10^-7 Bq ¹²⁵I particles) (n=15 per group). Six nude mice were randomly sacrificed to collect the tumor tissue and measure tumor volume and mass. TUNEL (TdT-mediated dUTP nick-end labeling) was used for detecting apoptosis of tumor cells, and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) for detecting the relative expression of Bax, caspase-3 and caspase-8. On the 28th day after implantation, the apoptotic rate in the low, medium and high dose groups was significantly higher than that in the control group, which in the medium and high dose groups was significantly lower than that in the low dose group (P<0.05). On the 28th day after implantation, the relative expression of Bax, caspase-3 and caspase-8 mRNA in the control group was significantly lower than that in the low, medium and high dose groups (P<0.05), which in the low dose group was significantly higher than that in the medium and high dose groups (P<0.05). ¹²⁵I particles can inhibit the growth of HGC-27 gastric cancer cell transplants and promote the expression of Bax, caspase-3 and caspase-8 mRNA in the tumor tissue. Low-dose ¹²⁵I particles are significantly more effective than medium- or high-dose ¹²⁵I particles.

Effect of radiotherapy on the expression of cardiovascular disease-related miRNA-146a, -155, -221 and -222 in blood of women with breast cancer

Breast cancer (BC) is one of the most important neoplasias among women. Many patients receive radiotherapy (RT), which involves radiation exposure of the thoracic zone, including the heart and blood vessels, leading to the development of cardiovascular disease (CVD) as a long-term side effect. The severity of CVD-related pathologies leads research on assessing novel CVD biomarkers as diagnostic, prognostic or therapeutic agents. Currently, the possible candidates include blood microRNAs (miRNAs). Previous studies have supported a role for miRNA-146a, -155, -221, and -222 in the progression of CVD. Our purpose was to evaluate the RT-induced modulation of the expression of these miRNAs in the blood of women with BC. Pre-RT control and post-RT blood samples were collected, and after miRNA isolation and reverse transcription, the levels of the selected miRNAs were measured by real-time PCR. Our results showed that miRNA-155 exhibited the lowest expression, while miRNA-222 exhibited the highest expression, followed by miRNA-221. The expression of each individual miRNA was positively correlated with that of the others both pre-RT control and post-RT and inversely correlated with age before RT. Furthermore, RT promoted the overexpression of the selected miRNAs. Their levels were also affected by CVD-linked clinical parameters, treatment and BC side. Modulation of the expression of the selected miRNAs together with other risk factors might be associated with the development of future cardiovascular pathologies. Further confirmatory studies are needed to assess their potential as possible biomarkers in the progression of or as therapeutic targets for RT-induced CVD in BC patients.

Crude Edible Fig (Ficus carica) Leaf Extract Prevents Diethylstilbestrol (DES)-Induced DNA Strand Breaks in Single-Cell Gel Electrophoresis (SCGE)/Comet Assay: Literature Review and Pilot Study

Fig (Ficus carica) trees are among the oldest plants on earth. The chemopreventive properties of constituent polyphenols and fiber that implicate figs in having a functional role in averting cancer have not been fully elucidated. We therefore hypothesized that fig leaf extract would inhibit (or attenuate) DES-induced DNA single-strand breakage in MCF10A human breast epithelial cells. To test this hypothesis, MCF10A cells were treated with DES (1, 10, 100 μM), crude fig leaf extract (5, 10, 15 μL), or concomitant doses of DES (100 μM)/fig leaf extract (5, 10, 15 μL). The cells were analyzed for DNA strand breakage using the SCGE/COMET assay with mean olive tail moment as a marker of DNA damage. DES induced DNA strand breaks at all treatment levels compared to DMSO and non-treatment controls. DES at concentrations of 1, 10, and 100 μM produced mean olive tail moments of 1.2082 (177.6%), 1.2702 (186.7%), and 1.1275 (165.7%), respectively, which were statistically significantly (p<0.05) higher than the DMSO control value (0.6803). Exposure to fig leaf extract produced no DNA damage. Rather, a desirable dose-dependent reduction in DES-induced DNA strand breaks was observed. Composite treatment of MCF10A cells with DES and fig leaf extract attenuated DES-induced DNA strand breaks. Taken together, these results suggest a potential mechanism for cancer chemoprevention. Additional studies are necessary to identify relevant active ingredients, confirm the mechanism of action, and further elucidate the therapeutic potential of fig leaf extract for early-stage breast cancer chemoprevention.

Overexpression of CLEC3A promotes tumor progression and poor prognosis in breast invasive ductal cancer

Introduction

The aim of this study was to evaluate the expression of C-type lectin domain family 3 member A (CLEC3A) and its clinical significance in breast invasive ductal cancer (IDC) as well as its effect on breast cancer (BC) cell proliferation and metastasis. In this study, the level of CLEC3A expression in The Cancer Genome Atlas (TCGA) datasets was analyzed.

Materials and methods

Clinical collected samples and BC cells were measured using quantitative reverse transcription polymerase chain reaction. Its correlations with patients’ clinicopathological characteristics were analyzed by Pearson’s chi-squared test. Overall survival (OS) analysis was performed by the Kaplan–Meier method and Cox’s proportional-hazards model. BC cell proliferation, migration, and invasion by CLEC3A knockdown were assessed using Cell Counting Kit-8 and colony formation assay, wound healing model and transwell assay, respectively, in BT474 cell line. Activities of survival factors and phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT) signaling were measured by testing key molecules using Western blot assay.

Results

CLEC3A expression was markedly higher in breast IDC tissues than normal breast tissues or adjacent normal tissue. Patients with high CLEC3A expression related to higher lymph node and poorer OS of breast IDC. CLEC3A knockdown by siRNA could inhibit the BC cells BT474 proliferation, migration, and invasion, together with a decrease in expression of key proteins in survival factors and PI3K/AKT signaling pathway.

Conclusion

Elevated CLEC3A expression may correlate with breast IDC metastatic potential and indicated a poor prognosis in breast IDC. CLEC3A knockdown inhibited BC cell growth and metastasis might be through suppressing PI3K/AKT signaling activity. These findings unravel that CLEC3A is a promising therapeutic target for BC in the future.