Cancer is a word with a very high rate of occurrence in today’s society, and it is also an important factor that affects the happiness and harmony of millions of families, and most people are “scared of talking about cancer”. In fact, as the saying goes, three feet of ice is not cold in a day. Cancer does not come without a cause and signs. Cancer undergoes three stages in the process of development: precancerous lesions, carcinoma in situ and invasive carcinoma. Many cancers can be nipped in the bud if attention is paid and treatment is given to them in the precancerous stage. Therefore, it is necessary for people to know some common knowledge about precancerous lesions to protect their own health and that of their family members. The so-called “precancerous lesion” refers to the intermediate state between normal tissues and cancer, which is a kind of abnormal phenomenon and clinical manifestation different from both normal tissues and cancer, such as mucous membrane leukoplakia, chronic atrophic gastritis, uterine cervical erosion, multiple adenomatous polyps in colorectum, some benign tumors, junctional nevus, etc. Some of them may develop into cancer after several years, and some of them may become cancerous. Some of them may become cancerous after several years, and some of them may be reversed. At this time, active treatment and protective measures can avoid or reduce the occurrence of cancer. For precancerous lesions, some ambiguities must be clarified: (1) most of the precancerous lesions will not evolve into cancer, only some of them may evolve into cancer; (2) precancerous lesions are not cancerous, therefore, precancerous lesions should not be equated with cancer; (3) precancerous lesions should not be enlarged, and some lesions not belonging to precancerous lesions, such as general skin nevus, common peptic ulcer and chronic gastritis, should be treated as precancerous lesions. 1. Mucosal white spots Mucosal white spots are white patchy damages occurring on oral mucosa, with 50-60 years old as the peak of incidence, mostly occurring in males. White spots are often seen on both cheeks, tip of tongue and edge of tongue. If the white spots are soft and smooth, and the touch of fingers is not obvious, it is not yet a big problem, i.e. there is no possibility of cancer. If the color becomes white, the surface becomes rough, and once the phenomenon of cracks and ulcers appears, it suggests the possibility of cancer. Generally, the white spots of oral mucosa of middle-aged and old people aged 50 to 70 are most likely to become cancerous. Cancer prevention strategy: First of all, avoid the factors that induce oral mucous membrane leukoplakia, such as smoking, drinking a lot of alcohol, eating spicy food, not paying attention to oral hygiene, etc. In terms of treatment, topical application can be used. In terms of treatment, local application of vitamin A and oral intake of vitamin A or retinoic acid tablets can help eliminate hyperkeratosis of epithelium. Meanwhile, some traditional Chinese medicines can also be taken for identification. Surgical excision, or electrocoagulation, freezing and other therapies can be considered for patients with the possibility of cancer. Avoid using corrosive drugs to remove white spots, because corrosive drugs have the danger of promoting cancer. 2.Chronic atrophic gastritis Chronic atrophic gastritis is a common disease, and also the most important precancerous disease that increases with age. Statistics show that the incidence rate of gastric cancer in those who have suffered from this disease for more than 11 years is 7%~13%. The course of the disease is as follows: chronic superficial gastritis – gastric mucosal atrophy – intestinal epithelial hyperplasia – heterogeneous hyperplasia – gastric cancer. Therefore, it is very important to understand the diagnosis and treatment of chronic atrophic gastritis precancerous lesions to prevent gastric cancer. Cancer prevention strategy The first step is early detection. If there are symptoms such as loss of appetite, nausea, belching, epigastric fullness or dull pain, especially after eating, or even upper gastrointestinal bleeding, emaciation, anemia, brittle nails, lingual inflammation or atrophy of tongue papilla, it is recommended to do gastroscopy and pathological examination of gastric mucosa to make a clear diagnosis. Patients who have been diagnosed as precancerous lesions of gastric cancer have a significantly higher incidence of gastric cancer than normal people. If effective measures are taken in time at this time, gastric cancer can be prevented or delayed to a certain extent. Specific measures are as follows: (1) Eradicate Helicobacter pylori, protect gastric mucosa, supplement acid, vitamins and trace elements (vitamin C, vitamin E and selenium, etc.), and adjust immune function. (2) Food should be fresh and rich in nutrients, ensuring adequate protein, vitamin and iron intake. Eat on time, do not overeat, do not eat food that is too cold or too hot, and do not use or use less stimulating condiments. Abstain from drinking alcohol, do not smoke; avoid taking anti-inflammatory painkillers for a long time, such as aspirin and corticosteroid drugs, in order to reduce gastric mucosa damage. (3) Chinese medicine treatment. Traditional Chinese medicine can reduce or disappear intestinal chemosis and heterogeneous hyperplasia and prevent gastric cancer. (4) Regular examination, gastroscopy and gastric mucosa pathologic examination if necessary. Fibrocystic breast disease Fibrocystic breast disease is a common breast disease among women, commonly found in women aged 30 to 50 years old. Patients often have swelling and pain in one or both breasts, which is as mild as pins and needles, and can involve the shoulder, upper limbs or chest and back. The pain is usually obvious before the onset of menstruation and decreases or disappears after the onset of menstruation. On examination, there are scattered rounded nodules in the breast, varying in size, tough and sometimes tender. Epidemiologic studies suggest that patients with fibrocystic breast disease have two to four times the chance of developing breast cancer later in life than the normal population. If the disease is accompanied by epithelial atypical hyperplasia, especially in severe cases, it has a higher possibility of malignant transformation and belongs to pre-cancerous lesions. Cancer prevention strategy Fibrocystic breast disease can be treated with non-surgical treatment in most cases, but because of the possibility of cancer, it is important to follow up closely and have regular medical checkups. Usually pay attention to whether there is fluid overflow from the breast, skewed nipple, and whether there is orange peel-like change on the surface. 4.Multiple colon polyps Multiple colon polyps are important precancerous lesions of colorectal cancer. It is a kind of small droplet-like meat protrusions growing out to the intestinal cavity, with no obvious symptoms clinically, which can gradually grow up, increase, and finally fill up the colon and block the intestinal cavity. The disease mostly develops after the age of 20. If it is not treated with timely surgery, it can turn into cancer around 40 years old. Once multiple colon polyps are detected by physical examination, the best way is to operate in time, and those who cannot be operated for the time being should be followed up regularly to prevent the occurrence of complications. At the same time, we should change the bad dietary habits such as high fat, high protein, high salt, low fiber, lack of coarse grains, fruits and vegetables, and predominantly meat. Obesity caused by irrational diet structure and little exercise is also a factor contributing to the development of colorectal cancer. 5. Cervical erosion Cervical erosion is often caused by chronic inflammation, and chronic inflammation may form a kind of inner foundation of carcinogenesis, which is favorable to the invasion of carcinogenic factors, leading to the transformation of cervical epithelial cells and the occurrence of cervical cancer. It is found that the incidence of cervical cancer in women with celiac disease is 7 times higher than that in those without celiac disease. Cancer prevention strategies Patients with celiac disease should undergo regular gynecological examinations, cervical smears to look for cancer cells, and those with severe celiac disease should be treated thoroughly and in a timely manner. Physiotherapy is the most effective and shortest treatment for cervical erosion. It is suitable for cases with larger erosion surface and deeper infiltration of inflammation, and can be cured with only one treatment. Physical therapy includes electrocoagulation, cryotherapy, laser therapy, microwave therapy, infrared condensation therapy, each with its own advantages and disadvantages. 6.Junctional nevus Junctional nevus is a brown or black rash, which may be slightly elevated, 2～8mm, round, with clear boundary, uniform color, smooth and hairless surface. It can occur in any part. Those occurring on palm and plantar and external genitalia are mostly junctional nevi. Junctional nevus is characterized by nevus cell activity at the junction of epidermis and dermis, and has a tendency of malignant transformation, especially the junctional nevus that grows on the palms of the hands, soles of the feet and other parts that are easily irritated should be more vigilant. Clinical findings show that some junctional nevi and mixed nevi may undergo malignant transformation and become malignant melanoma under the stimulation of certain factors. Cancer prevention strategy Although junctional nevi and mixed nevi have been proved to have a tendency to become malignant, the number of those that actually develop into malignant tumors is very small. At present, it is believed that repeated friction, needle picking and other stimuli, incomplete excision, light, electrocautery, corrosion with drugs and one’s own endocrine disorders may be the triggering factors to stimulate the malignant transformation of junctional nevus or mixed nevus into melanoma. When a nevus becomes malignant, there are some abnormal manifestations, which should attract special attention: (1) the growth speed is suddenly accelerated, and it is obviously enlarged in a short period of time; (2) there is a hard knot in the center of the nevus, or there are tiny pigmented spots or nodules scattered around the nevus in the form of satellites; (3) the color is obviously deepened compared with the previous one, or the color becomes uneven; (4) the surface of the nevus is moist or scabbed; (5) there is vesiculation, ulceration, hemorrhage and inflammation on the surface of the nevus; (6) the nevus has localized itching and pain; (7) the edge of the nevus was originally itchy and painful. (7) The edge of the mole is originally clear, but suddenly expands to the surrounding area with irregular edges and unclear boundaries with normal skin, or there is a reddish halo around the mole. If the above signs are found or malignant tendency is suspected, it is necessary to go to the hospital for examination as early as possible. Generally, the examination should adopt excision surgery, which is to remove the whole piece of the lesion together with the surrounding 0.5~lcm normal skin and subcutaneous fat and then do pathological examination. If it is confirmed that the lesion is malignant, then according to the depth of infiltration, it will be decided whether supplementary wide excision is needed. Once precancerous lesions are detected, one should not be alarmed, but should adopt a correct attitude, if surgical treatment is needed, surgery should be actively performed; if regular review is needed, regular review should be initiated. Do not be worried and carry a heavy burden of thought. Long-term mental tension can lower the immunity of the body and even prompt the normal cells in the body to become cancerous. Therefore, if we pay attention to diet, live a healthy and regular life, have early checkups when we find discomfort, and participate in regular medical checkups, we will be able to realize the three early signs of cancer: early discovery, early diagnosis, and early treatment, so as to truly prevent cancer before it occurs, and walk with happiness.