The cause of kidney cancer, like other cancers, is not known and may be related to many factors, chief among them being genetic and environmental factors.
Genetic factors
Heredity means that there are mutations in specific genes that can cause kidney cancer and that these mutations can be passed from generation to generation. Hereditary kidney cancers are also thought to be familial because they spread through the family. However, only 3-4% of kidney cancers are in fact familial, and the rest are considered to be disseminated. Sporadic refers to patients who have no family history of kidney cancer and whose cancer develops and grows in an unpredictable way.
Surveys have found a tendency for some kidney cancers to run in families, such as two brothers both having kidney cancer, or three to five people in a family successively having kidney cancer. Some hereditary diseases such as tuberous sclerosis and multiple neurofibromas can be combined with renal cell carcinoma; there are familial renal cancers with retinal hemangioma, which can be multifocal or intracapsular; and mutations in the VHL gene are also a cause of renal cancer.
A variety of genes have been found to be strongly associated with the development of hereditary kidney cancer, such as the VHL gene, c-MET gene, FH gene, and BHD gene. Therefore, those with a family history of kidney cancer should be especially vigilant.
Environmental factors
Smoking
The chemicals in the smoke inhaled by smoking enter the bloodstream, which can reach many organs and tissues, increasing the risk of many cancers, including kidney cancer. Studies show that the relative risk of kidney cancer increases by 54% in men and 22% in women who smoke, and the risk increases significantly with the amount smoked, and the longer you smoke, the higher your risk of cancer.
And smoking cessation campaigns are expected to reduce the incidence of kidney cancer in the coming years. There is no definitive answer to the relationship between kidney cancer and industrial carcinogens, but male smokers who are regularly exposed to cadmium industrial environments are significantly more likely to develop kidney cancer than the general population.
Obesity
Studies have shown that body mass index (BMI, a number derived by dividing weight in kilograms by height in meters squared) is associated with the development of kidney cancer, and that the higher the BMI, the higher the incidence of kidney cancer in people.
The study found that the high-fat, high-protein diet that most Americans are born with plays a major role in increasing the risk of kidney cancer; in contrast, a high intake of fruits and vegetables reduces this risk.
High blood pressure
Studies have shown that people with high blood pressure have an increased risk of kidney cancer, possibly because chronic high blood pressure causes kidney damage, making the kidneys more sensitive to associated carcinogens and thus more susceptible to kidney cancer.
High-risk groups
Based on the above risk factors, people with the following conditions may be at higher risk for kidney cancer than the general population, and early screening for kidney cancer is recommended:
- Patients with VHL (Von Hippel-Lindau syndrome) or other familial renal cancer syndromes and their immediate family members;
- Patients with end-stage renal failure usually have cysts (fluid cavities in the kidney), and 1% of these patients will eventually develop kidney cancer;
- Patients with tuberous sclerosis, a syndrome that causes benign skin damage, vascular damage to the brain and causes seizures or mental retardation, benign vascular lesions of the kidney (vascular smooth muscle lipomas), and kidney cancer.
These patients should have regular annual ultrasound and CT exams to rule out kidney cancer and practice good lifestyle habits to protect their kidney health.