Kidney cancer develops when cells in the kidney, most often in the tiny tubes that filter your blood, accumulate DNA mutations that let them grow unchecked. Three modifiable risk factors, smoking, excess body weight, and high blood pressure, together account for roughly 49% of cases. The median age at diagnosis is 65, and men are diagnosed nearly twice as often as women, with 24.4 new cases per 100,000 men compared to 12.3 per 100,000 women each year.
How Kidney Cancer Starts
Most kidney cancers are renal cell carcinomas, and they originate in the proximal tubule cells of the nephron, the part of the kidney responsible for reabsorbing nutrients and water from filtered blood. The earliest and most common genetic event in these cancers is the loss of function of a tumor suppressor gene called VHL, located on chromosome 3. When VHL stops working, the cell loses a key brake on growth and blood vessel formation. Additional mutations in genes that regulate how DNA is read and repaired then accumulate, pushing the cell further toward uncontrolled division.
Smoking
Smokers have a 38% higher risk of kidney cancer than people who have never smoked, based on a meta-analysis of 24 studies. The risk climbs with the number of cigarettes. Men who smoked a pack or more per day had roughly double the risk compared to nonsmokers. For women, the increase was smaller but still significant at about 58% for heavy smokers. The risk decreases after quitting, though it takes years to approach the baseline of someone who never smoked.
Excess Body Weight
Obesity is one of the strongest and most well-documented drivers of kidney cancer. The connection runs through insulin. When you carry excess weight, your body becomes less responsive to insulin, so the pancreas produces more of it. Chronically elevated insulin reduces the proteins that normally keep a growth-promoting hormone called IGF-1 in check. With more IGF-1 circulating freely, cells receive persistent signals to grow, divide, and avoid the normal self-destruct sequence that clears out damaged cells.
IGF-1 also encourages new blood vessel growth, which tumors need to sustain themselves. Research has confirmed that kidney cancer cells produce both IGF-1 and its receptor, creating a self-reinforcing loop where the tumor essentially feeds its own growth signals. This makes obesity not just a trigger for cancer development but a factor that can accelerate tumor progression once it begins.
High Blood Pressure
Chronic high blood pressure is independently linked to kidney cancer, even after accounting for weight and smoking. A large population-based study found that the risk increases in a dose-dependent pattern starting at a systolic blood pressure of 120 mm Hg and climbing from there. The proposed explanation centers on what sustained pressure does to kidney tissue: it triggers chronic low-grade inflammation, damages the lining of blood vessels, and forces kidney cells into a state of oxygen deprivation. That oxygen-poor environment activates pathways that drive abnormal cell growth and new blood vessel formation, the same pathways disrupted by VHL mutations.
Interestingly, people taking blood pressure medications had a higher observed rate of kidney cancer than those with untreated hypertension (35.8 versus 14.6 cases per 100,000 person-years). This likely reflects the fact that medicated patients tend to have more severe or longer-standing hypertension rather than that the medications themselves cause cancer, though some classes of blood pressure drugs, particularly certain diuretics and beta-blockers, were associated with higher risk than others.
Chronic Kidney Disease and Dialysis
People on long-term dialysis face a substantially elevated risk. In the United States, dialysis patients develop kidney cancer at roughly 3.7 times the rate of the general population. In Australia and New Zealand, that number reaches nearly 10 times the expected rate. The damaged, scarred kidneys of someone with end-stage kidney disease create an environment prone to cyst formation and abnormal cell growth, and the longer someone remains on dialysis, the more time these changes have to accumulate.
Chemical and Workplace Exposures
Trichloroethylene (TCE), an industrial degreasing solvent, is a confirmed cause of kidney cancer. Workers who inhale TCE or absorb it through their skin during metal cleaning, electronics manufacturing, or equipment maintenance face prolonged exposure. Because the U.S. military used TCE extensively to degrease equipment, contaminated soil and groundwater surround many current and former military bases, putting nearby communities at risk as well.
Certain painkiller formulations containing phenacetin, a compound removed from most markets decades ago, have also been linked to cancers of the kidney and renal pelvis. Modern over-the-counter painkillers do not contain phenacetin, but people who used these older formulations heavily may carry residual risk.
Inherited Genetic Conditions
A small percentage of kidney cancers are hereditary. The best-known genetic syndrome is Von Hippel-Lindau (VHL) disease, caused by an inherited mutation in the same VHL tumor suppressor gene that is disrupted in most sporadic kidney cancers. People born with one faulty copy of VHL need only lose function of the remaining copy in a kidney cell for tumor development to begin, which is why they tend to develop kidney cancer at younger ages and sometimes in both kidneys. VHL disease also causes tumors and cysts in other organs, including the brain, spine, and eyes.
While VHL is the most recognized hereditary cause, other rare genetic syndromes also raise kidney cancer risk. If multiple close relatives have had kidney cancer, especially before age 50, a genetic basis is worth investigating.
Why Men Are at Higher Risk
Men develop kidney cancer at nearly double the rate of women. The reasons are partly behavioral: historically, men have had higher rates of smoking and occupational chemical exposure. But biology plays a role too. Hormonal differences, body composition patterns, and variations in how the kidneys metabolize certain compounds all contribute. Even in studies that adjust for smoking and weight, a gap between men and women persists.
How Physical Activity Lowers Risk
Regular exercise is one of the most effective ways to reduce kidney cancer risk, and the benefit is substantial. People who met standard physical activity guidelines through walking or running had a 61% lower risk of developing kidney cancer compared to those who exercised below recommended levels. Those who exercised at double the recommended amount saw a 76% reduction. Each additional hour of moderate activity per week reduced risk by about 2%.
Exercise likely works through several channels at once. It lowers circulating insulin and IGF-1, directly countering the growth signals that drive kidney tumors. It reduces body fat and blood pressure, addressing two major risk factors simultaneously. There is also evidence that regular physical activity decreases DNA damage from a process called lipid peroxidation, where unstable molecules attack kidney cell DNA. Maintaining a healthy weight, staying physically active, and not smoking collectively address nearly half of all kidney cancer risk.