This study will include 80 subjects after radical breast cancer resection, collect blood samples of the above subjects, observe and quantify the characteristic changes of cfDNA in the blood of breast cancer subjects after surgery, and establish a computational biological model based on next generation sequencing to monitor breast cancer MRD;

This study will include 80 subjects after radical breast cancer resection. The results of CA15-3, CEA, color Doppler ultrasound and other traditional postoperative monitoring examinations for breast cancer, as well as 5ml of peripheral venous blood, were collected on the day of enrollment/the 7th day after adjuvant treatment/the 3rd, 6th, 9th, 12th, 15th, 18th, 21st, 24th, 30th and 36th months after surgery. We observe and quantify the characteristic changes of cfDNA in the blood of breast cancer subjects after surgery, and establish a computational biological model based on next generation sequencing to monitor breast cancer MRD;

Inclusion Criteria:

• 1. Age ≥ 18 years old, gender not limited; 2. Obtain plasma samples from the subjects during a 3-year follow-up period; 3. The subjects fully understand the study and voluntarily sign the informed consent form; 4. Able to cooperate with a 3-year follow-up visit to the hospital; 5. The physical fitness status score (ZPS) of the ECOG scoring criteria for the subjects must be ≤ 1; 6. Life expectancy ≥ 5 years; 7. Subjects who meet the following criteria:

  1. Histopathology confirmed primary breast cancer (unlimited molecular type);
  2. Radical breast cancer resection is expected;
  3. Adopting postoperative adjuvant therapy or preoperative neoadjuvant therapy;

Exclusion Criteria:

• 1. The subject is pregnant or breastfeeding; 2. Serious mental illness or drug abuse; 3. Unable to obtain the subject's plasma during this period; 4. If the subject has a non primary malignant tumor of the breast with a clear pathological diagnosis within 5 years before enrollment: 5. If the subject has suspected non breast malignant tumors (such as B-ultrasound, CT, etc.) on imaging within the past year of enrollment, but without pathological confirmation; 6. Clinical suspicion of distant metastatic lesions; 7. The subject has received any blood product infusion therapy within the past 30 days; 8. Known carriers of pathogenic genetic mutations;

Eighty patients with breast cancer were diagnosed in the Second Affiliated Hospital of Zhejiang University School of Medicine.