When high tumor markers occur during or after chemotherapy for breast cancer, further tests are needed to evaluate the effectiveness of treatment and to confirm whether recurrence or metastasis has occurred. Tumor markers of the breast are of great clinical significance in evaluating the progression of the disease. If tumor markers are elevated during or after chemotherapy for breast cancer patients, it is necessary for professional doctors to evaluate the recent treatment in combination with the patient’s condition, consider whether the treatment at this stage is effective or not, and arrange for the patient to undergo a comprehensive imaging examination to find out whether the disease is progressing, whether the disease is recurring or metastasized, etc. After a clear understanding, the patient can take corresponding treatment plans in combination with the recurrence situation or metastatic site. If tumor markers are elevated, it is recommended to go to the hospital in time to clarify the condition and receive standardized treatment.