Background:

Breast cancer is the most common cancer in women, and advances in early detection and treatment have led to steadily improved survival rates. Today, nearly 80% of breast cancer survivors are over 50 years of age. With longer survival, comes a greater burden of chronic disease, particularly cardiovascular disease (CVD), which is more common in breast cancer survivors than in the general population. This elevated risk is driven by treatment-related effects, such as chemotherapy- and radiotherapy-induced cardiotoxicity, metabolic changes including (therapy-associated) weight gain, and shared lifestyle risk factors such as obesity and physical inactivity. In routine clinical care, approximately 65% of breast cancer patients undergo local radiotherapy (RT) and will receive a planning computed tomography (CT) scan. These scans, while intended for RT planning, also capture valuable information on coronary artery calcifications (CAC), a well-established marker risk factor of CVD risk.

The ARTILLERY-CarDI study is a multinational decision impact trial which will evaluate calculating CAC-based CVD risk (Agatston score) and communicating personalized, risk-based management recommendations to breast cancer patients.

Aims and outcomes:

In this study, CVD risk is estimated based on the manual CAC (Agatston) score using RT planning CT scans and a corresponding CVD risk-based recommendation is provided to breast cancer patients. The main aim of this study is to disclose this estimated CVD risk to treating physicians and patients and investigate how this risk affects:

1. breast cancer treatment (retrospectively) and cardiovascular care (i.e., no further action, recommendation for lifestyle changes, referral to a cardiologist or general practitioner (GP)), and
2. patients' satisfaction with their decision to receive their estimated CVD risk and the corresponding CVD risk-based management.

Secondary aims are to evaluate whether the knowledge of estimated CVD risk and corresponding CVD-risk based management impacts patients' decisions regarding their lifestyle and habits, decisional conflict regarding lifestyle decision changes, patient reported outcomes (PROs) and changes in CVD risk factors and CVD treatment.

Methods:

ARTILLERY-CarDI is a multinational, multicenter, prospective decision impact trial, designed as a within-subject trial in which participants serve as their own controls. A total of 1,000 patients with breast cancer will be enrolled over 1.5 years across five centers in four countries (the Netherlands with two participating centers, Germany, Portugal, and Denmark). Each participant will be followed for six months.

The intervention is the CVD risk estimation based on the CAC (Agatston) score using RT planning CT scans, and the subsequent disclosure of the estimated CVD risk and corresponding CVD risk-based management to the patient using the ARTILLERY manual. The CAC (Agatston) score will be measured after the RT planning CT scan is made, which is usually one or two weeks before the start of RT. The Agatston score is a validated method for CVD risk assessment using the amount of CAC. CVD risk is categorized in 5 groups with an Agatston score of 0, 1-10, 11-100, 101-400, and >400. In the current trial, endpoints will be analyzed according to low, moderate, and high-CVD-risk groups corresponding to score ranges 0-10, 11-100, and >100, respectively.

Following a study-specific manual , eligible patients will be referred to a cardiologist or GP if a previously unknown moderate to high risk of CVD according to CAC is determined (Agatston score >10). Thereafter, these patients will be treated accordingly as part of standard care. We expect that the timely measurement of estimated CVD risk by the amount of CAC on a planning CT scan and the disclosure of CVD risk-based management is beneficial for patients. The CVD risk measurement will lead to the identification of breast cancer patients with a previously unknown moderate to high estimated CVD risk and possibly undertreated cardiac conditions. The disclosure of CVD risk-based management is intended to empower patients to manage their own physical health and well-being. Also, we expect that the CVD risk measurement and CVD risk-based management will create more awareness among doctors and citizens about CVD risk in breast cancer patients. A potential side-effect of CAC- based CVD risk measurement and disclosure of CVD risk-based management is that, some patients may experience increased anxiety leading to dissatisfaction or regret about their decision to participate. The Satisfaction with Decision (SWD) questionnaire will be used to measure patients' satisfaction about their decision as one of the primary outcomes and the level of anxiety by the Hospital Anxiety and Depression Scale, at baseline, at one month and at six months after the intervention.

Inclusion Criteria:

• diagnosed with breast cancer or ductal carcinoma in situ
• Planned for radiotherapy
• From 35 years of age onwards

Exclusion Criteria:

• Pregnancy
• Breastfeeding