A Prospective Study to Observe Clinical Outcomes in Patients Receiving Antiplatelet or Anticoagulant Therapy for Cancer-Associated Acute Ischemic Stroke

The goal of this observational study is to learn about the effectiveness and safety of antiplatelet and anticoagulant treatments in people with a history of cancer who have acute ischemic stroke. The main questions it aims to answer are: * Are there differences in the risk of another stroke between people receiving antiplatelet treatment and those receiving anticoagulant treatment? * Are there differences in the risk of bleeding between the treatment groups? * Which clinical characteristics, imaging findings, cancer-related factors, and blood test results are associated with treatment outcomes? Participants will: * Receive antiplatelet treatment, anticoagulant treatment, or a combination of both, as selected by their treating physicians during routine clinical care. * Provide clinical information and blood samples for the study. * Complete follow-up assessments approximately 30, 90, 180, and 360 days after the stroke. Researchers will compare recurrent stroke, bleeding, other blood clot-related events, functional recovery, and survival among participants receiving different antithrombotic treatments. The study will not assign or change participants' treatments.

Inclusion Criteria: * Age 18 years or older. * Diagnosis of acute ischemic stroke confirmed by clinical evaluation and brain imaging. * Enrollment within 7 days after symptom onset or the time the participant was last known to be well. * History of a malignant tumor, regardless of whether the cancer is currently active or inactive. * Written informed consent provided by the participant or the participant's legally authorized representative. Exclusion Criteria: * Hematologic malignancy. * Primary intracerebral hemorrhage, subarachnoid hemorrhage, or another non-ischemic type of stroke. * Transient ischemic attack without evidence of acute ischemic stroke. * Pregnancy or breastfeeding. * Known severe congenital coagulation disorder. * Collection of research blood samples would delay intravenous thrombolysis, mechanical thrombectomy, or other necessary treatment. * Blood samples that do not meet the prespecified collection requirements or show severe hemolysis. * Inability to obtain reliable medical history or outcome information from the participant, medical records, or an authorized representative.