Many cancers have early signs, yet people often think they are minor and ignore them, missing the best time for treatment. Generally speaking, if an abnormal body condition persists for 3-6 months without remission or even continues to worsen, then it is definitely time to see a doctor. Especially, people with family history of cancer, smokers and drinkers need to pay extra attention. 1. Recurrent fever Fever is usually a common symptom caused by infection, but unexplained fever may be a dangerous sign. When cancer spreads to other organs in the body, it usually leads to fever. Blood cancers such as lymphoma and leukemia also have fever symptoms. Necessary tests include: X-ray chest, CT scan, MRI, etc. 2. Skin abnormalities Skin cancer may occur in people of all ages, and is especially dangerous for people who are often exposed to the sun. Skin cancer usually initially manifests as specific moles. For example, junctional nevus may be a precancerous lesion of melanoma. Some junctional and mixed nevi of the skin can become malignant and malignant melanoma when stimulated by certain factors. Although junctional nevi and mixed nevi have been shown to have a tendency to become malignant, very few actually develop into malignant tumors. It should be noted that repeated irritation such as friction and needle picking, incomplete excision, erosion with drugs and one’s own endocrine disorder may be the triggers to stimulate the malignant transformation of junctional or mixed nevi into melanoma. In addition, painless skin keratinization may also be an early sign of skin cancer. The general specific symptoms include: round rash-like abnormal changes in the skin, local flattening or bulging, brownish yellow or black scabs on the surface, and patients do not feel pain, mostly on the face and back of hands. 3.Fatigue and weakness Feeling fatigue and weakness around the body is a common manifestation of cancer development, but for leukemia, intestinal cancer and stomach cancer, fatigue may be felt at the early stage of development. Fatigue is also seen in normal people. Fatigue weakness of cancer is different from ordinary fatigue, which will disappear after a rest, while fatigue of cancer will find it hard to improve no matter how to rest. 4. Continuous cough or hoarseness Continuous and incessant cough may be the precursor of lung cancer, especially for smokers. And hoarseness may be a sign of head or neck tumors, as tumors in these areas may compress the vocal cords or damage the nerves that control them. The increasing incidence of head or neck tumors in young people today warrants attention. 5. Painless lymph node enlargement Lymphoma most often has enlarged lymph glands (nodes) as the first symptom, especially in the neck, underarm or groin. If there are swollen lymph nodes in one or more places with hard texture but no pain, you should be concerned about lymphoma, and it is better to go to the hospital for examination in time. Change in bowel habits Prostate cancer may lead to frequent urination, while colon cancer may lead to long-term constipation, diarrhea, or change in stool appearance (e.g. thinning of stool). Prostate and colon cancers are genetically related, so people with a family history of such cancers should pay extra attention. 7. Weight loss If you have neither increased exercise nor reduced diet, but your weight has inexplicably dropped, you should seek medical attention promptly. This is because tumors can affect metabolism, reduce the body’s ability to absorb nutrients such as protein and calories, and consume muscle and fat. Alcoholics and people with family history of the disease should pay extra attention. 8.Unexplained pain If pain occurs in a certain part of the body and lasts for more than a week, the cause should be identified as soon as possible, because unexplained pain may be a sign of cancer. Long-term abdominal pain is a symptom of liver cancer, stomach cancer, pancreatic cancer and colorectal cancer, chest pain is a symptom of esophageal cancer and lung cancer, and bone pain is a symptom of cancer metastasis. 9.Abnormal bleeding Blood in sputum may be a sign of lung cancer; blood in stool is likely to be a symptom of bowel cancer except for hemorrhoids (besides blood in stool, if the tumor grows near the anus, it may also show symptoms such as thinning of stool and increasing frequency, or even cause difficulty in stool); blood in urine without pain or difficulty in urination, excluding stones or inflammation, should be alert to bladder cancer or kidney cancer; bleeding from skin may be skin cancer. 10.Uncured ulcers Oral ulcers that do not heal for a long time may be a sign of oral cancer. People who smoke, drink alcohol and are infected with HPV (human papillomavirus) have a higher chance of developing oral cancer. If the ulcer does not heal in 3-6 months, it is time to see a doctor. 11.Difficulty in swallowing Long-term difficulty in swallowing, pain behind the sternum when eating, foreign body feeling in the esophagus and indigestion may be signs of laryngeal cancer, esophageal cancer and gastric cancer, so you should receive X-ray chest or gastroscopy as soon as possible. 12.Atypical hyperplasia of breast Atypical hyperplasia of breast may be a precancerous lesion of breast cancer. Simple breast hyperplasia is not cancerous, but if the ductal epithelium is highly hyperplastic and atypical, it may be a precancerous lesion. Atypical hyperplasia of breast tissue, intraductal papilloma and cystic hyperplasia of breast are generally regarded as precancerous lesions of breast cancer. If women find lumps in the breast, they should consult a doctor in time for further examination to clarify the cause. 13.Chronic atrophic gastritis Chronic atrophic gastritis may be a precancerous lesion of gastric cancer. Most of the patients with chronic gastritis can receive timely treatment with combination of Chinese and Western medicine, and the effect is relatively good and will not cause cancer. However, some gastric cancers coexist with or occur on the basis of certain benign lesions such as chronic atrophic gastritis, and most of these gastric diseases have existed for a long time, which makes patients relax their vigilance of gastric cancer more easily. To confirm the diagnosis of stomach cancer, gastroscopy must be performed. 14. Virus-induced celiac disease Virus-induced celiac disease may be a precancerous lesion of cervical cancer. “Cervical erosion” is a phenomenon on the surface of the cervix, not a disease. If there is no specific clinical manifestation, it usually does not require treatment. The symptoms of early cervical cancer and precancerous lesions are similar to those of “cervical erosion”, so blind treatment may cause the spread of cancer. women after the age of 21 should undergo cervical smear examination once a year, and after the age of 30, HPV (human papillomavirus) examination can be combined. 15. Lung nodules Most of the lung nodules are benign and only a small percentage belong to precancerous lesions or lung cancer. If a lung nodule is found, do not be overly alarmed and do not ignore it. They should be diagnosed in time to clarify their nature and be observed or treated according to the actual situation. Lung nodules are in many cases only inflammatory lesions. This disease is more prevalent in people over 40 years of age, so this group, or those at high risk with a family history of the disease, should try to have low-dose spiral CT screening for early lung cancer once a year.