If chemotherapy can be tolerated for three times, it is still necessary to continue chemotherapy and cannot be discontinued arbitrarily. For postoperative chemotherapy, such as postoperative breast cancer, postoperative lung cancer, etc., 4-6 cycles of chemotherapy are needed, and if chemotherapy has been given for 3 cycles, sometimes it is not possible to achieve the best therapeutic effect, and there is a higher chance of recurrence and metastasis in the postoperative period. For postoperative chemotherapy of colorectal cancer, 8-12 cycles of chemotherapy are needed, and if only 3 cycles of chemotherapy are given, it is certainly far from enough. If it is advanced malignant tumor, 3 times of chemotherapy is also not enough, there is a possibility that the tumor will continue to grow in a short period of time after the termination of chemotherapy, and if the tumor has progressed and then continue chemotherapy, it may cause tumor resistance, and then the effective rate of chemotherapy will be greatly reduced.