This study will prospectively monitor cancer patients receiving chemotherapy (including molecular targeted therapies) for cardiovascular adverse events using biomarkers and imaging. The goal is to develop a predictive model for major adverse cardiovascular events (MACE) in this population by integrating both local factors (e.g. central venous catheter-related thrombosis) and systemic factors (e.g. age, comorbidities, genetic predisposition). An active surveillance system employing periodic cardiac evaluations (ECG, echocardiography) and biomarker measurements (troponin T, NT-proBNP) will enable early detection of cardiotoxic effects. The impact of these adverse events and the monitoring strategy on patients' quality of life will also be assessed.

Cancer patients are at heightened risk of cardiovascular complications due to both their disease and its treatments. Many chemotherapeutic and targeted agents (e.g. anthracyclines, trastuzumab, bevacizumab, tyrosine kinase inhibitors) carry cardiotoxic potential, leading to diverse manifestations of MACE such as heart failure, arrhythmias, ischemic heart disease, valvular dysfunction, hypertension, thromboembolism, and others. As cancer survival improves and newer therapies are widely used, the incidence of treatment-related cardiac toxicity continues to rise. Early cardiotoxic changes are often subclinical, making proactive monitoring essential. Research has shown that cardiac biomarkers can rise before left ventricular ejection fraction declines, enabling "pre-symptomatic" detection of cardiotoxicity. By quantitatively analyzing the predictive value of each indicator for MACE, the study aims to construct a comprehensive risk prediction model for precise cardiovascular risk evaluation in cancer patients. Both local risk factors (e.g., indwelling catheter-related thrombosis) and systemic factors (e.g., age, hypercoagulability, body mass index) will be incorporated, reflecting the interplay of factors contributing to MACE. Genetic biomarkers will also be explored: blood samples are collected for genomic analysis (such as SNP genotyping and whole genome sequencing) to identify genetic polymorphisms associated with increased susceptibility to therapy-related MACE. By comparing patients who develop cardiovascular events to those who do not, we will characterize the incidence, timing, affected organs, and clinical presentation of MACE in cancer patients. Patient-reported quality of life will be evaluated using validated questionnaires, to determine how the occurrence of adverse cardiovascular events (and the implementation of active monitoring) affects daily functioning and overall well-being. Ultimately, this study's findings will provide a scientific basis for individualized risk stratification and preventive interventions in cardio-oncology, supporting optimized clinical strategies to mitigate cardiovascular risk without compromising effective cancer treatment.

Inclusion Criteria:

1.Adults (age > 18 years) with a pathologically confirmed malignant tumor (any type of cancer); 2.Currently receiving or planning to receive chemotherapy (including regimens containing molecular targeted drugs) as adjuvant treatment for cancer; 3.Willing and able to participate in the study with provision of informed consent, and agreeable to provide required clinical data and biological samples.

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Exclusion Criteria:

1. Incomplete basic patient information or medical records (missing key data necessary for the study);
2. Failure to complete the full course of planned chemotherapy at the study center (e.g., patient did not adhere to or finish all cycles of adjuvant chemotherapy at our institution);
3. History of severe acute cardiovascular or cerebrovascular events within 6 months prior to enrollment, including acute heart failure, acute myocardial infarction, acute intracerebral hemorrhage (stroke), malignant arrhythmia, or New York Heart Association (NYHA) Class IV/V heart failure;
4. Missing essential pre- or post-chemotherapy evaluations: patients who did not undergo complete baseline or end-of-treatment assessments (such as blood routine, hepatic/renal function, coagulation profile, cardiac enzymes (troponin T), NT-proBNP (or BNP), 12-lead ECG, and echocardiogram)

The study population comprises adult cancer patients receiving adjuvant chemotherapy (including those receiving molecular targeted agents as part of therapy) at included centers (and collaborating centers) between June 1, 2025 and June 30, 2027. Eligible patients include those with any malignant solid tumor or hematologic malignancy who are starting a planned course of postoperative (adjuvant) chemotherapy. Enrollment will be consecutive and non-selective - all patients meeting inclusion criteria (and no exclusion criteria) in the participating centers during the accrual window will be invited to participate. Patients are typically enrolled at the time of initiation of chemotherapy, with baseline cardiovascular assessments performed prior to or at the first cycle of treatment. The cohort will be followed prospectively through their chemotherapy course and for up to 6 months after completion of therapy.