Can rectal cancer be contagious? The answer is no. There are four ways of metastasis, namely, direct spread, lymphatic metastasis, blood metastasis and implantation metastasis, which are not infectious by other ways. However, when the skin is damaged, the cancer cells will be implanted when it comes into contact with it. Therefore, there is no evidence to show that rectal cancer is contagious. Generally speaking, viruses are contagious, but the strength of each virus varies. After virus infection, only one percent of people have clinical disease, and many more people do not have disease and are in the state of recessive infection. Whether a virus infection develops or not has an important relationship with the body’s defense function. If the body’s defense function is strong after rectal cancer surgery, even if there is a viral infection, the disease may not occur for life. It has been established that there are more than 100 viruses that can cause more than 30 kinds of tumors in animals. Some viruses can also cause tumors in humans. Thus, there is an objective material basis for the possible transmission of tumors. Viruses or particles of such viruses have been found in human Burkitt’s lymphoma, leukemia, nasopharyngeal carcinoma, breast cancer, cervical cancer, and melanoma. As to whether rectal cancer is contagious, foreign medical doctors have made long-term observations of patients in malignant cancer sanatoriums and found that patients with cancer with ulcers, and patients without ulcers with cancer, who have been together for a long time, have never had mutual contagion among them. On the other hand, there are numerous cancer patients treated by doctors, but the cancer rate of doctors is not higher than that of the general population. It is a widespread and abundant fact that animals with cancer and healthy animals live together in the same room, and no direct cases of transmission have been found. In hospitals where patients with different types of cancer have been living in the same room for a long time, no mutual transmission has been found for many years. In addition, in experiments on animals, blood from the spleen of chickens with filtered sarcoma was injected into healthy chickens, which also developed filtered sarcoma. Others had fleas that had sucked the blood of mice with breast cancer and then bit healthy mice, and they succeeded in inoculating the tumors on healthy mice. These facts show that tumors in general are not contagious, and general contact with tumor patients is not contagious. Therefore, until today, all hospitals do not adopt isolation system for tumor patients.