People usually find it hard to understand why doctors ask patients to undergo chemotherapy after they have been cut off from a tumor, but it seems that they have not yet come to terms with it. Whenever we talk about chemotherapy, many people first associate it with vomiting, hair loss, and mental depression, or decreased resistance, and they feel scared of the side effects of chemotherapy. Isn’t chemotherapy a bit hard to accept for patients who have just recovered from surgery? Why do doctors recommend us to receive chemotherapy soon after tumor removal? Characteristics of malignant tumors Malignant tumors are systemic diseases. Tumors usually grow up in the primary foci, and local infiltration and distant metastasis will occur with the prolongation of the tumor growth time, including metastasis through lymphatic vessels, or metastasis to various organs such as the liver, lungs, brain, and bones through the blood circulation, so as to lose the chance of surgical resection by operation. The most common discussion about tumors is can the tumor be cut? Is the tumor cut? Yes, the current treatment principle for most tumors is: surgical resection as the core comprehensive treatment. For middle and late-stage tumors, it is often difficult to achieve the best results by surgery alone, and chemotherapy is the most important adjuvant treatment. If the tumor is detected early and limited to the local organs (CT or MRI does not find local or distant metastasis), the surgeon still has the chance to “finish off” the locally developed tumor through local excision and scavenging. However, the problem is that many patients with tumors that have not yet developed distant metastases after detailed examination are confirmed to have developed distant metastases one or two years after surgical resection. Since the primary lesion has been removed, where did the metastasis come from? In fact, most of these metastatic lesions develop from microscopic metastases that existed before surgery but could not be detected by clinical examination. These small metastatic lesions, which exist but cannot be detected by examination, can be called subclinical metastases. It is because of the existence of such potential metastases that some of the patients’ tumors “recur and metastasize” after a period of time after surgery. The fact is that most of the tumors have been more or less metastasized when they are found. Because of the existence of such potential metastatic foci, the probability of tumor recurrence after surgery is very high if there is no postoperative review or chemotherapy. The frightening thing about tumor cells is that they are tenacious, and only individual microscopic tumor cells can develop into a mass of metastatic foci, which can be described as a spark that can start a prairie fire. The value of chemotherapy How to deal with these tiny metastatic foci lurking in the body? In order to eliminate these small portion of “escaped” tumor cells, doctors draw on the experience of non-solid tumor treatment and use chemotherapy to eliminate these tiny cancer cells. Postoperative adjuvant chemotherapy has been proven to be beneficial in improving the survival rate of most tumors, especially for patients with intermediate and advanced tumors. The later the tumor is found, the higher the probability of metastasis, therefore, for patients with advanced stage, doctors usually recommend systemic chemotherapy in a timely manner after surgery, in order to eliminate or control these tiny metastatic foci that may exist. Practical tests have proved that chemotherapy is of great value in preventing tumor recurrence and metastasis after surgery. In view of the rapid growth of tumor cells, people have screened out the most commonly used chemotherapeutic drugs from practice. These chemotherapeutic drugs have the strongest killing effect on the vigorously growing cells and kill the rapidly growing tumor cells as well as some cells in our body, such as the cells of gastrointestinal tract, hair follicle cells and hematopoietic cells, etc. Therefore, the traditional cytotoxic chemotherapeutic drugs have the strongest killing effect on the rapidly growing tumor cells. Therefore, the most common effects of traditional cytotoxic chemotherapy drugs after chemotherapy are vomiting, diarrhea, hair loss, anemia, and low resistance. A New Look at Chemotherapy Most people are impressed by the side effects of chemotherapy through movies and TV shows: vomiting until you vomit bile, losing hair until there is none left, and all kinds of discomfort all over the body. But the reality is not like this, not everyone will have such a serious reaction. Each of us has a different body type, and the side effects of chemotherapy vary greatly. Not everyone will have such a severe reaction to chemotherapy, and you can see many people in the hospital who do not lose their hair as they do during chemotherapy, and who take walks as they do during chemotherapy, so how to minimize the side effects of chemotherapy is a subject of learning, so there is no need to hold phobia of chemotherapy, and we should encourage and help the patient to divert their attention to minimize the discomfort of chemotherapy. Traditional chemotherapeutic agents can be compared to “indiscriminate explosives”, which have a strong killing effect on both normal cells and tumor cells, and can be said to hurt the enemy a thousand times and harm themselves eight hundred times. In recent years, molecular targeting drugs have received good results in tumor treatment, they can kill tumor cells in a targeted manner and retain normal cells, which is called “missiles that distinguish between enemy and self”. For patients with economic conditions, molecular targeted drug therapy can be used to kill tumor cells in a targeted manner and reduce the damage of chemotherapeutic drugs on normal cells. In a word, malignant tumor is a systemic disease, surgery can eliminate the large force or nest of tumor, but it can’t do anything for the scattered and sporadic cancer cells, while the effect of chemotherapeutic drugs is systemic, and postoperative adjuvant chemotherapy can kill them, so that the patients can survive for a long time, or even be cured. Chemotherapy is valuable in preventing tumor recurrence and metastasis after surgery. We need to weigh the pros and cons and consider them comprehensively to see whether we can bear the side effects of chemotherapy after surgery.