Cancer, also known as malignant tumor, is a disease caused by malfunctioning mechanisms that control cell growth and proliferation. As one of the major public health problems in the world, cancer greatly jeopardizes human health and will become the number one killer of human beings in the new century. Due to the different occurrence sites, pathological forms and development stages of cancer, the symptoms of various cancer patients will be different. In order to achieve the goal of early detection, early diagnosis and early treatment, according to the characteristics of the incidence of cancer in China, we summarize the common symptoms of 11 kinds of cancers and the high-risk groups for the reference of patients. Gastrointestinal Tumor–Stomach Cancer More than 70% of early stomach cancers have no obvious symptoms, with the development of the disease, indigestion symptoms of unknown cause will suddenly appear, and it is more stubborn and fast progressing; the prominent manifestation is the rapid decrease of appetite, the feeling of fullness and discomfort in the abdomen after eating, which will be accompanied by a significant reduction of body weight, or there is no stomach pain (“heartburn”) in the past, or there is no stomach pain in the past. Or people who did not have stomach pain (“heart pain”) in the past suddenly have recurrent stomach pain; although they used to have stomach pain, the intensity, nature and duration of pain suddenly change recently, and the drugs that were effective in treating the pain become ineffective or inefficient, which need to be noted and observed. Colorectal cancer Above 30 years old, if there are abdominal discomfort, hidden pain, abdominal distension, change of bowel habit, constipation, diarrhea or alternating, feeling of falling down, blood in stools, followed by anemia, fatigue and weakness, and a lump is felt in the abdomen, colorectal cancer should be considered. Early symptoms are mainly painless blood in stools, which is red or bright red, very similar to the symptoms of early internal hemorrhoids, and in the late stage, the blood in stools is mostly dark red, mixed with mucus blood stools or pus blood stools in feces. Hepatobiliary and Pancreatic Tumors–Liver Cancer Liver cancer has a relatively insidious onset, and there are no specific symptoms in the early stage. When the patients have obvious clinical symptoms, the condition often belongs to the middle or late stage. However, if patients with chronic hepatitis or liver cirrhosis have tingling or worsening pain in the right upper abdomen or liver area, discomfort, loss of appetite, progressive dyspepsia, accompanied by persistent diarrhea and obvious weight loss, they should be highly alerted. Lung Cancer Cough is the most common incipient symptom of lung cancer, which mainly consists of paroxysmal irritating dry cough, no sputum or only a small amount of white foamy sputum, and pus sputum may appear secondary to infection. If there is no improvement after 2 weeks of anti-inflammatory treatment, one should be alert to the possibility of lung cancer. If there is no improvement after 2 weeks of anti-inflammatory treatment, one should be alerted to the possibility of lung cancer. Or if there is a change in the nature of cough on the basis of the original chronic cough, or even accompanied by “tracheal ringing” and “shortness of breath”, one should pay attention to it. Another warning sign of lung cancer is intermittent recurrence of small amount of bloody sputum, or sputum with blood. Head and neck tumor–Thyroid cancer Thyroid cancer lacks characteristic clinical manifestations in early stage, but more than 95% of patients have anterior neck nodule (or mass). Children and women over 40 years old should be especially alerted when they have isolated, irregular, hard mass in front of their necks with unclear boundary and poor mobility. Breast tumor – breast cancer Abnormal changes in the breast, such as palpation of breast lump, distension, micro-concavity (“dimple sign”), thickening and reddening of the skin, nipple deformation, retraction, or scaling, pain or tenderness, and enlargement of axillary lymph nodes, etc., in non-lactating women. Sudden onset of unilateral nipple drainage (milky, bloody, watery fluid). Gynecological tumor – cervical cancer Common symptoms of cervical cancer include: vaginal contact bleeding, vaginal discharge out of a large amount of rice soup-like, purulent or pus-blood fluid with malodor, frequency of urination, urgency of urination, anal swelling, constipation, lower abdominal pain, sciatica, swelling and pain in the lower limbs in the late stage. The focus is on irregular vaginal bleeding, contact bleeding and excessive leukorrhea. Urological system tumor – prostate cancer Most of the early stage have no symptoms, middle and late stage can show lower urethral obstruction symptoms such as urinary frequency, urinary urgency, dysuria and other compression symptoms, and bone pain, spinal nerve compression passes, accompanied by anemia, swelling of the lower limbs and other metastatic symptoms. Leukemia Acute leukemia in children and adolescents is often of acute onset. Common first symptoms include fever, progressive anemia, significant bleeding tendency or bone and joint pain. The slow onset of the disease is common in the elderly and some young patients, and the disease progresses gradually. In addition, a few patients may have convulsions, blindness, toothache, swollen gums, pericardial effusion, paraplegia of both lower limbs as the first symptoms. Lymphoma Lymphoma is a malignant tumor originated from lymphohematopoietic system, which mainly manifests as painless enlarged lymph nodes, enlarged liver and spleen, and all tissues and organs of the whole body can be involved, accompanied by systemic symptoms such as fever, night sweating, emaciation and itching.