I often encounter tumor patients from all over the country in my outpatient clinics. Recently, I met a patient from Henan Province, a young man in his thirties, who is an IT professional. He originally had hepatitis B, but never had any hepatitis. Due to his busy work schedule, he often works overtime and stays up late, and does not take medical checkups. Recently, he kept feeling weak in walking, not eating well, and lying in bed at night, his right abdomen also felt a bit bloated. After examination in a local hospital, a tumor of the size of a “doll’s head” was found, and lymph node metastasis appeared, and liver cancer was diagnosed. Such a big tumor is obviously not open to surgery, what should we do? He played his professional strengths, researched various information on the Internet and decided to use the latest “immunotherapy”. He told me that the experience he gained from his research was that immunotherapy “has no side effects and is effective”. So, he took two injections of PD-1 antibody locally. Three days ago, he was thinking about getting the third shot, but when he looked in the mirror in the morning, he noticed that his eyes were a little yellow, so he went to the hospital to have his blood drawn, and his liver function index bilirubin exceeded 3 times and transaminase exceeded 5 times. The tumor not only did not shrink, but also grew 2 cm larger. Is immunotherapy really “no side effects” and “good effect”? Today, I will talk with you about the misconceptions of tumor immunotherapy. Misconception 1: Immunotherapy is to improve immunity, there is no side effect. This is the “experience talk” of my old patients in the outpatient waiting area and new patients to exchange immunotherapy. It’s true that many patients get a PD-1 antibody shot every two or three weeks, and feel good about themselves when they can drive home after a one-hour drip. In fact, immunotherapy drugs have side effects just like other anti-tumor drugs. Moreover, the side effects of immunotherapy are more widespread and insidious than other anti-tumor drugs. Why are the side effects of immunotherapy more widespread? It starts from the principle of how immunotherapy works. Immunotherapy drugs represented by PD-1 inhibitors work because they specifically activate our own immune cells to kill the “bad molecules – tumor cells”. If the body’s immune system remains in balance after PD-1 treatment, it can kill bad bacteria, viruses and cancer cells without affecting the body’s normal cells. However, once the immune cells are “over-activated”, they can become “unrecognizable” and cause damage to the cells of normal human tissues, which results in side effects. You may have heard of lupus erythematosus and rheumatoid arthritis, which belong to the category of “autoimmune diseases”. The essence of autoimmune diseases is that the immune system is over-activated and starts to attack normal cells and organs. As you can see here, the core of tumor immunotherapy is usually a short-term activation of the immune system, so there are more or less side effects. Common toxicities associated with the use of PD-1 antibodies include skin toxicity, thyroid toxicity, gastrointestinal toxicity, hepatotoxicity, pulmonary toxicity, etc. The most serious one is cardiotoxicity, and its use requires strict monitoring and standardized management of adverse side effects. However, I still want to emphasize that compared to chemotherapy, and even compared to many targeted drugs, the overall side effect rate of immunotherapy represented by PD-1 is low, so we do not need to panic too much. The young patient at the beginning of our article had hepatotoxicity – autoimmune hepatitis. The incidence of this condition in the total population of immunotherapy is about 5-10%, which is still relatively low. Myth 2: Simple blood check before immunotherapy, liver and kidney function can be injected As I have already emphasized, immunotherapy has a wide range of side effects, you can not just check the blood routine, liver and kidney function and then inject. In our daily treatment, several indexes need to be checked, including blood routine, liver and kidney function, autoantibodies, hormone level, and cardiopulmonary function assessment, and autoimmune diseases and serious cardiopulmonary dysfunction need to be excluded before immunotherapy can be initiated. In addition to the basic assessment before the first immunotherapy treatment, ECG, follow-up of blood test and comprehensive assessment of drug side effects should be performed before each injection. Once adverse reactions occur, they can be detected and intervened in time and usually do not cause serious consequences. If the drug is used blindly without standardized follow-up, the occurrence of autoimmune pneumonia, hepatitis or even myocarditis is very dangerous and can even be life-threatening. We have encountered PD-1-induced autoimmune myocarditis, which is rare, with an incidence of only a few per 10,000, but once it happens, the situation is very serious, causing heart failure and a mortality rate of up to 50%. Myth 3: Immunotherapy is so expensive, and the tumor can shrink after using it. This is another misconception. Although immunotherapy has achieved good efficacy and approved indications in many solid tumors in recent years, there is still a considerable difference in efficacy in different types of tumors. Taking primary liver cancer as an example (mainly referring to hepatocellular carcinoma), the therapeutic efficiency of single-agent application of PD-1, whether imported or domestic, does not exceed 20%, mostly ranging from 13%-17%. In other words, with single-agent PD-1 antibody, only 1 out of 5 patients may have tumor shrinkage after using it. Most patients need to be treated with a combination of targeted drugs, which can greatly improve the efficiency of immunotherapy. After a certain period of immunotherapy, there are still some patients with treatment resistance and tumor progression again. At this time, it is recommended to participate in clinical studies of new drugs, especially recommended to participate in international multicenter clinical studies, to be able to have the opportunity to use the most cutting-edge international anti-cancer drugs for treatment and maximize the survival. IV. Conclusion Tumor immunotherapy, as a powerful tool in cancer treatment, can have advantages and disadvantages. Its effectiveness against tumor is obvious to all of us, but its side effects should not be ignored and used blindly. The only way to bring the best survival benefit to tumor patients is to have a good understanding of the efficacy and side effects of immunotherapy, to carry out standardized treatment, and to follow up regularly.