High-grade ductal carcinoma in situ of the breast generally does not require chemotherapy, so there is usually no question of the length of chemotherapy. High-grade ductal carcinoma in situ of the breast, suggesting stage 0, does not need chemotherapy. The growth of carcinoma in situ does not break through the basement membrane, so after complete surgical resection, endocrine therapy can be chosen appropriately and chemotherapy is not needed to reduce the risk of metastasis. For patients with high-grade ductal carcinoma in situ of the breast, comparative statistics between chemotherapy and no chemotherapy found that there is almost no difference in survival rate and the probability of recurrence and metastasis between the two. Therefore, high-grade ductal carcinoma in situ of the breast is recommended not to undergo chemotherapy in order to avoid the side effects caused by chemotherapy. Patients with high-grade ductal carcinoma in situ of the breast are recommended to consult the breast surgery department of regular hospitals.