The essential definition of cancer and tumors, and an in-depth analysis of sub-health high-risk groups and precancerous diseases.

Chapter 5 Cancer, Tumors, and Sub-health What is cancer? In medicine, malignant tumors originating from epithelial tissue are called cancer. Squamous cell carcinoma, which occurs in squamous epithelial cells, is commonly found in areas of the body originally covered by squamous epithelium, such as the skin, mouth, lips, cervix, vagina, esophagus, larynx, and penis. Adenocarcinoma, which occurs in glandular epithelial cells, is commonly found in the stomach, intestines, breast, liver, thyroid gland, salivary glands, bronchi, and uterus. Cancer is a common name for all malignant tumors. When malignant tumors grow in these organs, they are respectively called skin cancer, stomach cancer, esophageal cancer, and intestinal cancer. Cancer is more common in middle-aged and elderly people over 40 years old. In terms of metastasis, cancer often metastasizes via the lymphatic system. What is a tumor? A tumor is a new growth formed by the excessive proliferation or abnormal differentiation of normal cells that are developing or maturing in the body under the long-term influence of certain adverse factors, forming a mass in a localized area. Unlike normal tissues and cells, malignant tumor cells do not grow according to the normal metabolic patterns of cells. Instead, they become unrestrained and uncontrolled, and do not die normally. This leads to abnormal cell morphology, function, and metabolism, which can damage the structure and function of normal tissues and organs. Malignant tumor cells can also infiltrate and spread to surrounding areas, and even metastasize to other organs and tissues, continuing to multiply and posing a great threat to human health or life.

Section 1 High-risk groups for cancer are sub-healthy groups for cancer. I. High-risk groups for cancer are sub-healthy groups for cancer. "High-risk" groups refer to some people in society who have a high risk of developing a certain type of cancer. However, it must be pointed out that not all high-risk groups will develop cancer, nor does it mean that people who are not high-risk groups will not develop cancer. Due to certain reasons, the incidence of a certain type of cancer in this group is many times higher than that in the general population. Therefore, this group becomes the key target for the prevention of a certain type of cancer. (1) Those who have long been engaged in or in contact with the following jobs are considered high-risk groups, such as asbestos, benzene, cadmium, chromium, nickel, arsenic, wood chips, radiation, radon, ultraviolet rays, alkylating agents, aromatic amines, polycyclic aromatic hydrocarbons, diethylstilbestrol, vinyl chloride, 4-aminobiphenyl, dichloromethyl ether, soot and tar, pesticides, rubber, metallurgy, furniture manufacturing, etc. (2) People with a family history of cancer and people with precancerous diseases. (3) Heavy or long-term smokers, passive smokers, alcoholics, and people with other special habits. (4) Other conditions, such as hepatitis B and C, AIDS, obesity, infertility, not breastfeeding, early sexual intercourse, multiple sexual partners, homosexuality, chronic schistosomiasis, etc.

II. Common Precancerous Diseases: Early detection and treatment of precancerous diseases in sub-healthy individuals can reduce the incidence of cancer. Precancerous diseases refer to certain diseases in the body, some of which may later develop into cancer. Therefore, prevention and treatment of precancerous diseases are of great significance in cancer prevention. Currently, the following categories of precancerous diseases are generally recognized: (I) Skin and Mucous Membrane Diseases: Senile keratosis, often occurring on the face and arms; leukoplakia, often occurring in the mouth, esophagus, vulva, vagina, cervix, etc.; chronic ulcers and fistulas that do not heal for a long time, often occurring in the mouth, stomach, lower legs, anus, etc.; pigmented nevi in ​​areas prone to friction, such as pigmented nevi growing on the palms, soles, neck, waist, etc. (II) Breast Diseases: Fibrocystic breast disease, fibroadenoma, intraductal papilloma. (III) Gastrointestinal diseases: Chronic gastric ulcers that are difficult to cure, especially callous ulcers, single or multiple polypoid adenomas of the gastrointestinal tract, chronic atrophic gastritis, residual stomach, and severe esophageal epithelial hyperplasia. (IV) Urogenital system diseases: Cervical erosion, ectopic testis, undescended testis or cryptorchidism, phimosis or paraphimosis, and hydatidiform mole. (V) Infectious diseases and parasitic diseases: Chronic and persistent viral hepatitis and cirrhosis; Schistosomiasis japonica, Schistosomiasis haematobium, Clonorchiasis sinensis; AIDS (Acquired Immunodeficiency Syndrome). (VI) Certain hereditary diseases: Familial polyposis colon, ataxia-telangiectasia, and xeroderma pigmentosum. (VII) Certain benign tumors.