It is possible that cancer patients may not survive for a long time if they cannot eat, but it is not certain how long they can live, and it depends on whether they have done other treatments. If the patient cannot eat but apply intravenous nutrition support or enteral nutrition tube for enteral nutrition support, it is possible to survive for a longer period of time, such as more than one month or even longer, which can only be seen while treatment. If you can’t eat and don’t do other nutritional support treatment, most of the survival time is less than half a month, but it is not easy to determine the exact days, and it depends on whether the patient has multi-organ failure. Generally, the main cause of death in advanced cancer patients is organ failure, and of course, severe malnutrition will aggravate organ failure. When cancer reaches the end stage, there is no good treatment, only to strengthen the companionship, apply nutritional support, pain relief and other medications.