BACKGROUND:~Invasion and metastasis are the main reason of death in metastatic cancer, and abundant evidence find circulating tumor cells(CTCs) take the core position in breast and colorectal cancer metastasis.~Platelets play multiple role to facilitate the epithelial to mesenchymal transition of tumor cells and protect CTCs to survival in the circulation, which enrolled in the whole process of metastasis.~Several clinical trials and observational study have validate the primary and secondary prevention effect of aspirin to both breast and colorectal cancer.~OBJECTIVES:~Determine the effect of aspirin on CTC number of metastatic breast and colorectal cancer;~Determine the effect of aspirin on CTC subtype (epithelial/mesenchymal/mixed type) of metastatic breast and colorectal cancer.~ELIGIBILITY:~Adults age from 18-75 years old.~Patients were diagnosed for metastatic breast or colorectal cancer by pathology.~Patients who were not currently receiving intravenous chemotherapy , oral administrated with capecitabine was permitted. Concurrent endocrine therapy ( for at least 2 months before enrollment), bisphosphonate therapy, and/or monoclonal targeted therapy were permitted.~No disease of hemorrhagic tendency or history of non-steroid drug allergy.~CTCs≥5 / 7.5ml blood~STUDY DESIGN:~Aspirin will be administered orally once a day in 28-day cycles.~The CTC was evaluated every 28 days for 2 months.
The purpose of this study is to determine whether Aspirin could affect the number and subtype of circulating tumor cells of metastatic breast cancer and colorectal cancer.