The kidneys are located in the upper posterior part of the abdominal cavity, or the lumbar back, and have two left and two right sides, shaped like broad beans and protected by the posterior ribs. The function of the kidneys is to filter the waste and excess water and salt from the blood. This function is accomplished by the glomeruli within the kidneys. The glomerulus consists of a cluster of tiny blood vessels coiled into a spherical shape and surrounded by a peritoneal membrane. When blood enters the glomerulus, the water, salts and small molecules can be filtered out, while large particles such as red blood cells, white blood cells and proteins cannot be filtered out of the blood. Each glomerulus is connected to a renal tubule at the end, and the filtered material is concentrated and reabsorbed in the tubule to form urine. Urine flows from the kidneys through the ureters and into the bladder. Despite the importance of the kidneys, half a kidney is fully capable of performing its excretory function. In the United States, 1% of the population has only one kidney, but they live a normal life. Some people’s kidneys have even lost their functions and live on hemodialysis. I. Pathogenesis Kidney cancer is the cancer of the cells in the kidney. Renal cell carcinoma is the most common type of kidney malignant tumor, accounting for 85%. It ranks second among urological tumors, with a male to female ratio of 2:1. The incidence rate is higher in urban than in rural areas, and it is more likely to occur between 50 and 70 years old. Migratory cell carcinoma accounts for 6%-7% of renal malignancies, which originate from the union of kidney and ureter, that is, the renal pelvis. In addition, 5% to 6% of renal malignancies are seen in pediatric patients and are nephroblast carcinomas. If the tumor cells originate from the connective tissue of the kidney, it is called renal sarcoma. Renal cell carcinoma is usually a single mass. Sometimes multiple tumors can be present in one kidney or both kidneys at the same time, with an incidence of 2% to 3%. Kidney cancer can metastasize through blood or lymphatic tract, and once metastasis occurs, it is not easy to cure. Risk factors The factors that can induce tumors are called cancer-causing risk factors, including environmental and work risk factors. 1.Smoking: 30% of men and 25% of women with kidney cancer are caused by smoking. The risk of kidney cancer in smokers is twice as high as that in nonsmokers. Migratory cell carcinoma is especially associated with smoking. 2.Some occupations such as leather, asbestos, cadmium industry. 3.Genetic factors: Kidney cancer has a familial tendency to develop, and the number of brothers with the same disease or in the same family can be as high as 3~5 people. Genetic mutations can lead to certain diseases, such as tuberous sclerosis and multiple neurofibromas. 4.Bad lifestyle, such as high-fat diet, alcohol consumption, overweight, etc. 5.Coffee may increase the chance of kidney cancer in women. 6.Related drugs: long-term use of painkillers containing finasteride, abuse or overuse of compounded aspirin (painkillers) or diuretics. 7, History of blood transfusion, long-term hemodialysis, economic and cultural background. 8.High estrogen level, generally men have 2 times more kidney cancer than women. Abnormal manifestations Kidney cancer develops insidiously, and about 25% of patients have metastasis when they visit the doctor. There are almost no symptoms in the early stage of kidney cancer, and some patients are discovered during physical examination or ultrasound. More than half of the patients first appear symptoms other than urinary tract, such as weakness, poor mental health, loss of appetite, emaciation, anemia, abnormal liver function, hypertension, hypoglycemia, etc. The typical symptoms of kidney cancer are not manifested until late stage, and the main symptoms are: 1. Hematuria is the most common, accounting for 60%~70%, which is manifested as intermittent, painless hematuria in the whole process of the naked eye, mostly accompanied by streaky blood clots. Hematuria is caused by tumor invasion into renal pelvis and calyces and tumor surface rupture and bleeding. 2.Lower back pain About 50% of patients have dull pain or hidden pain in the back of the affected side, which can be gradually aggravated and is persistent. When tumor tissue necrosis, detachment or blood clots pass through ureter, it can cause unbearable severe colic. 3.Mass can be palpated in the posterior lumbar region or upper abdomen in about 10% of cases. The mass is hard, with uneven surface or nodules, often without pressure pain, and can move up and down with breathing. When the tumor invades adjacent organs and lumbar muscle, the mass is fixed. 4.Fever is a common early manifestation of kidney cancer, which can be low fever or high fever, and the body temperature can reach 39~40℃ in high fever and persistently does not subside. There are 2%~3% of patients only have fever. The fever may be cancer fever. Most of the patients can gradually return to normal body temperature after kidney tumor removal. 5. Anemia accounts for about 30%. Anemia is caused by tumor toxin or destruction of large amount of kidney tissue, which inhibits hematopoietic function and hematuria. 6.The manifestation of internal division thou disorder is the characteristic of renal cell carcinoma, which manifests as hypertension (40% appear), hypoglycemia, male breast development, decreased libido, hirsutism, amenorrhea and so on. These symptoms may disappear after kidney cancer resection. If the above symptoms do not disappear after kidney cancer surgery, it indicates poor prognosis. Preventive health care 1. Actively carry out cancer prevention education, popularize cancer prevention knowledge, understand the early signals and symptoms of kidney tumor, early diagnosis and early treatment. 2. Quit smoking, avoid radiation and use hormones carefully. 3.Workers in cadmium and lead industrial environment should pay attention to protection and regular physical examination. 4.Cultivate good dietary habits, do not eat moldy, rotten, smoked or pickled food, preferably into light food, appropriate intake of fish, eggs and a small amount of animal meat. Properly control the intake of sugar and salt. 5, life should be regular, the elderly should be appropriate exercise according to the physical condition. 6.People who take medicine for a long time must pay attention to drinking more water to reduce the damage to kidney. 7.During the treatment of kidney cancer, pay attention to dietary adjustment and reasonably supplement certain tonic products that can improve the immune function of the body. 8.Patients over 40 years old who have painless hematuria should go to a specialized hospital for examination as soon as possible. 9.Patients with family history of kidney cancer should pay attention to regular physical examination. 10.Avoid strenuous activities and weight-bearing for 3 months after kidney cancer surgery to prevent secondary bleeding. Keep the bowel movement smooth and use drugs carefully to avoid damaging kidney function. 11.Review: review every 1-3 months, and review every six months to a year if the condition is good, and adhere to comprehensive treatment. 12.It is important to insist on physical examination for early detection of kidney cancer. The kidney is deeply located and surrounded by other organs than the abdomen. Early kidney tumors are not easy to show symptoms, therefore, after the age of 40, it is better to have a health checkup once a year. Ultrasound examination of abdomen can detect tumors with diameter of 1cm and above. Advanced awareness and good habits can enable early detection and treatment of diseases.