1.Stomach cancer early symptoms of cancer: Sudden appearance of unexplained indigestion symptoms, which are relatively stubborn and fast progressing; the prominent manifestations are rapid decrease in appetite, abdominal fullness and distension and discomfort after eating, as well as significant weight loss. In addition, people who did not have stomach pain (“heartburn”) in the past suddenly have recurrent stomach pain; although they had stomach pain in the past, the intensity, nature and duration of the pain suddenly change recently, and the drugs that were effective in treatment become ineffective or unsatisfactory. 2.Esophageal cancer early symptom: the feeling of delayed swallowing food, stagnation or slight choking, which can subside by itself, but can appear again after several days, recurring and gradually worsening. Or when swallowing or eating, it always feels like there is localized pain in the sternum. Usually, it feels like there is a foreign body in the esophagus and it is not related to eating, it persists, and drinking water and swallowing food cannot make it disappear. 3.Early symptoms of cancer – liver cancer: Early liver cancer has no specific symptoms, if there are any, they are mostly some complex manifestations of pre-cancerous diseases. However, patients with chronic hepatitis or cirrhosis should be highly alert if they have stabbing pain or increased pain in the right upper abdomen or liver area, physical discomfort, loss of appetite, progressive indigestion, accompanied by persistent diarrhea and significant weight loss. 4.Early symptoms of cancer of rectal cancer: Anyone over 30 years old who has abdominal discomfort, hidden pain, bloating, change in stool habit, constipation, diarrhea or alternately, feeling of falling, and ambassador with blood, followed by anemia, fatigue and weakness, and a lump in the abdomen, should consider the possibility of colorectal cancer. The first alarm signal of colon cancer is the limited and intermittent hidden pain along the colon area. The first alarm signal of colon cancer is the intermittent vague pain along the colon, and the obvious falling sensation with blood in the stool is a signal of rectal cancer (colon cancer includes colon cancer and rectal cancer).