Are stomach cancer, lung cancer and rectal cancer contagious?

Are gastric cancer, lung cancer, and colorectal cancer contagious? In principle, they are not contagious, but they may be related to infectious diseases during their occurrence and development. For example, hepatitis B itself is contagious. In my country, it is an important cause of liver cancer, and many liver cancer patients have hepatitis B in the early stages. We can say that some tumors are caused by infectious diseases, but direct transmission of tumors generally does not exist.

Cancer is a common disease that is preventable and treatable. It is indeed difficult to treat, especially in the middle and late stages, but if detected and treated early, most tumors can be cured.
While treating patients' physical pain, oncologists have the obligation to help patients recover psychologically and build up confidence in overcoming the disease. People have various attitudes and psychological activities when they are sick. Some people are open-minded and optimistic, while many are fragile and desperate. For the same symptoms and the same stage of illness, the former has a better prognosis than the latter because their immune status is different. Even if the drug enters the body, it can only work if the patient actively mobilizes it. It can be seen that the patient's mental state plays a very important role.