For patients with adjuvant chemotherapy after cancer surgery, the frequency of chemotherapy is limited, and it is not necessary to continue chemotherapy, because excessive chemotherapy will bring serious side effects, which is not worth the candle. For patients with advanced tumor and palliative chemotherapy, long-term chemotherapy may be needed, so it is necessary to choose mild chemotherapy drugs with little side effects, such as long-term oral chemotherapy drugs, or targeted therapy and endocrine therapy with little side effects. The doctor will choose the appropriate chemotherapy scheme and cycle according to the patient's condition and physical condition, and must not overtreatment.
Because chemotherapy has toxic and side effects, doctors will decide the frequency and time interval of chemotherapy according to the metabolic characteristics of chemotherapy drugs, the size of side effects and the tolerance of people. The toxic and side effects of many chemotherapy drugs are superimposed and have dose limits. If it exceeds a certain cumulative dose, it can't be used again. For patients with postoperative adjuvant chemotherapy, chemotherapy is generally done for about half a year. Different tumors, different chemotherapy drugs and different chemotherapy time will be different.
If the tumor has metastasized in a large area, there is no cure and only palliative chemotherapy can be done. For patients with palliative chemotherapy, the role of chemotherapy is to control tumor growth, or try to slow down tumor growth and metastasis. The tumor is very cunning, and it will develop drug resistance after a certain period of use, so it is necessary to constantly change the chemotherapy regimen. We call it first-line chemotherapy. First-line chemotherapy cannot be changed into second-line chemotherapy, and second-line chemotherapy cannot be changed into third-line chemotherapy.
The question of "how long is chemotherapy" should be "different from person to person and from illness", and it cannot be generalized. But the general principles are "individualization" and "pertinence", that is to say, the design and treatment should be based on each patient's own situation. On the one hand, it is necessary to ensure the maximum killing of tumor cells, on the other hand, it is necessary to try not to add extra pain to patients. At the same time, it is necessary to prevent patients from being extremely weak, leading to recurrence and metastasis.