Coronary Artery Disease and Breast Radiation Therapy

Radiation-induced coronary artery disease during immune checkpoint inhibitor therapy: a case report

Radiation-induced coronary artery disease (RICAD) poses a serious concern for cancer patients post radiotherapy, typically emerging after over a decade. Immune checkpoint inhibitors (ICIs), known for cardiotoxicity, are increasingly recognized for causing cardiovascular complications. Here we report the case of a 63-year-old man with metastatic lung cancer who developed coronary artery disease during his third-line therapy with an ICI (nivolumab) and an antiangiogenic agent (bevacizumab), 3 years post chest radiotherapy. Angiography revealed relatively isolated stenosis in the left main coronary artery ostium, consistent with the radiotherapy site, with no other risk factors, suggesting RICAD. The potential for ICIs to accelerate RICAD development should be considered and necessitates careful surveillance in patients receiving both radiotherapy and ICIs.

IL-33/soluble ST2 axis is associated with radiation-induced cardiac injury

Radiotherapy for treating breast cancer is associated with cardiac damage. This study aimed to investigate the role of the interleukin (IL)-33/soluble receptor ST2 (sST2) axis in radiation-induced cardiac injury. Expressions of IL-33 and sST2 were detected in breast cancer patients following radiotherapy, radiation-induced cardiac damaged mice model, and cardiomyocytes using quantitative real-time PCR (qRT-PCR) and immunohistochemical assay. Cardiac injury was evaluated through an ultrasound imaging system and hematoxylin & eosin staining. The transcriptional factor was assessed using dual-luciferase reporter assay and chromatin immunoprecipitation. The results indicated that IL-33 and sST2 were highly expressed in breast cancer patients, which further elevated post-6 months but reduced after 12 months of radiotherapy. Radiation induces cardiac dysfunction and elevated IL-33 and sST2 levels in a time-dependent manner. However, silencing of IL-33 decreased sST2 expression to alleviate radiation-induced cardiac dysfunction. The IL-33 could be transcriptional activated by TCF7L2 by binding to IL33 promoter sites, which mutation alleviated cardiomyocyte injury caused by radiation. Additionally, radiation treatment resulted in higher levels of TCF7L2, IL-33, and sST2 in cardiomyocytes, and TCF7L2 knockdown reduced IL-33 and sST2 expression. In conclusion, TCF7L2 transcriptional-activated IL-33 mediated sST2 to regulate radiation-induced cardiac damage, providing novel insights into radiotherapy-induced cardiac damage.

Surface-guided DIBH radiotherapy for left breast cancer: impact of different thresholds on intrafractional motion monitoring and DIBH stability

PURPOSE

To compare two left breast cancer patient cohorts (tangential vs. locoregional deep-inspiration breath-hold - DIBH treatment) with different predefined beam gating thresholds and to evaluate their impact on motion management and DIBH stability.

METHODS

An SGRT-based clinical workflow was adopted for the DIBH treatment. Intrafractional monitoring was performed by tracking both the respiratory signal and the real-time displacement between the isocenter on the daily reference surface and on the live surface ("SGRT shift"). Beam gating tolerances were 5 mm/4 mm for the SGRT shifts and 5 mm/3 mm for the gating window amplitude for breast tangential and breast + lymph nodes locoregional treatments, respectively. A total of 24 patients, 12 treated with a tangential technique and 12 with a locoregional technique, were evaluated for a total number of 684 fractions. Statistical distributions of SGRT shift and respiratory signal for each treatment fraction, for each patient treatment, and for the two population samples were generated.

RESULTS

Lateral cumulative distributions of SGRT shifts for both locoregional and tangential samples were consistent with a null shift, whereas longitudinal and vertical ones were slightly negative (mean values < 1 mm). The distribution of the percentage of beam on time with SGRT shift > 3 mm, > 4 mm, or > 5 mm was extended toward higher values for the tangential sample than for the locoregional sample. The variability in the DIBH respiration signal was significantly greater for the tangential sample.

CONCLUSION

Different beam gating thresholds for surface-guided DIBH treatment of left breast cancer can impact motion management and DIBH stability by reducing the frequency of the maximum SGRT shift and increasing respiration signal stability when tighter thresholds are adopted.

Is radiation-induced arteriopathy in long-term breast cancer survivors an underdiagnosed situation?: Critical and pragmatic review of available literature

PURPOSE

Although considered exceptional, radiation-induced arteriopathy in long-term breast cancer survivors involves three main arterial domains in the irradiated volume, namely axillary-subclavian, coronary, and carotid. Stenosis of medium-large arteries is caused by "accelerated" atherosclerosis, particularly beyond 10 years after long-forgotten radiotherapy. The present review aims at summarizing what is known about arteriopathy, as well as the state of the art in terms of diagnosis and therapeutic management.

DIAGNOSIS

Pauci-symptomatic over years, the usual clinical presentation of arteriopathy involves arm pain with coldness due to subacute or critical ischemia (arterial occlusion), wrongly attributed to an exclusive neurological disorder, and more rarely transient ischemic accident or angina. Evaluation of the supra-aortic trunks by computed tomography and/or magnetic resonance angiography visualizes artery lesions, while Doppler ultrasonography in expert hands assesses diagnosis and downstream functional impact. In severe cases, more invasive angiography directly visualizes long irregular arterial stenosis (full-field radiotherapy), allowing accurate prognosis and treatment.

MANAGEMENT

Requires early diagnosis to enable initiation of medical treatment that increases blood flow (aspirin) as soon as moderate stenosis is detected, combined with correction of vascular risk factors. In intermediate cases, these therapeutic measures are completed by revascularization strategies using transluminal angioplasty-stenting (wall thickness). Antifibrotic treatment is useful in advanced cases with combined radiation injuries.

CONCLUSION

In follow-up of long-term breast cancer survivors with node irradiation, myocardial infarction is treated even if radiotherapy is forgotten, while recognition and diagnosis of chronic arm ischemia due to subclavian artery stenosis needs to be improved for appropriate therapeutic management.

Does deep inspiration breath hold reduce plan complexity? Multicentric experience of left breast cancer radiotherapy with volumetric modulated arc therapy

PURPOSE

Volumetric modulated arc therapy (VMAT) for left breast treatments allows heart sparing without compromising PTV coverage. However, this technique may require highly complex plans. Deep Inspiration Breath Hold (DIBH) procedure increases the heart-to-breast distance, facilitating the dose sparing of the heart. The aim of the present work was to investigate if the cardiac-sparing benefits of the DIBH technique were achieved with lower plan modulation and complexity than Free Breathing (FB) treatments.

METHODS AND MATERIALS

Ten left side breast cases were considered by two centers with different treatment planning systems (TPS) and Linacs. VMAT plans were elaborated in FB and DIBH according to the same protocol. Plan complexity was evaluated by scoring several complexity indices. A new global score index accounting for both plan quality and dosimetric parameters was defined. Pre-treatment QA was performed for all VMAT plans using EPID and Epiqa software.

RESULTS

DIBH-VMAT plans were associated with significant PTV coverage improvement and mean heart dose reduction (p < 0.003), increasing the resulting global score index. All the evaluated complexity indices showed lower plan complexity for DIBH plans than FB ones, but only in few cases the results were statistically significant. All plans passed the gamma analysis with the selected criteria.

CONCLUSIONS

The DIBH technique is superior to the FB technique when the heart needs further sparing, allowing a reduction of the doses to OARs with a slightly lower degree of plan complexity and without compromising plan deliverability. These benefits were achieved regardless of the technological scenarios adopted.

Radiation dose to the left anterior descending coronary artery during interstitial pulsed-dose-rate brachytherapy used as a boost in breast cancer patients undergoing organ-sparing treatment

Purpose

To assess dose received by the left anterior descending (LAD) coronary artery during interstitial pulsed-dose-rate brachytherapy (PDR-BT) boost for left-sided breast cancer patients undergoing organ-sparing treatment.

Material and methods

Thirty consecutive pT1-3N0-1M0 breast cancer patients boosted between 2014 and 2015 with 10 Gy/10 pulses/hour PDR-BT following a computed tomography (CT) simulation with the multi-catheter implant were included. The most common localization of primary tumor were upper quadrants. Patients were implanted with rigid tubes following breast conserving surgery and whole breast external beam irradiation (40 Gy/15 or 50 Gy/25 fractions). Computed tomography scans were retrospectively reviewed and LADs were contoured without and with margin of 5 mm (LAD_5mm). Standard treatment plan encompassed tumor bed determined by the surgical clips with margin of 2 cm. Dosimetric parameters were extracted from the dose-volume histograms.

Results

The mean D₉₀ and V₁₀₀ were 10.3 Gy (range: 6.6-13.3), and 42.0 cc (range: 15.3-109.3), respectively. The median dose non-uniformity ratio (DNR) was 0.50 (range: 0.27-0.82). The mean doses to LAD and LAD_5mm were 1.0 Gy and 0.96 Gy, and maximal doses were 1.57 Gy and 1.99 Gy, respectively. Dose to the 0.1 cc of the LAD and LAD_5mm were 1.42 Gy and 1.85 Gy (range: 0.01-4.98 Gy and 0.1-6.89 Gy), respectively.

Conclusions

Interstitial multi-catheter PDR-BT used as a boost for left-sided breast cancer is generally associated with low dose to the LAD. However, higher dose in individual cases may require alternative approaches.

Cardio-Oncology: An Update on Cardiotoxicity of Cancer-Related Treatment

Through the success of basic and disease-specific research, cancer survivors are one of the largest growing subsets of individuals accessing the healthcare system. Interestingly, cardiovascular disease is the second leading cause of morbidity and mortality in cancer survivors after recurrent malignancy. This recognition has helped stimulate a collaboration between oncology and cardiology practitioners and researchers, and the portmanteau cardio-oncology (also known as onco-cardiology) can now be found in many medical centers. This collaboration promises new insights into how cancer therapies impact cardiovascular homeostasis and long-term effects on cancer survivors. In this review, we will discuss the most recent views on the cardiotoxicity related to various classes of chemotherapy agents and radiation. We will also discuss broadly the current strategies for treating and preventing cardiovascular effects of cancer therapy.