Renal cancer is cancer that starts in the kidney. The most common type, renal cell carcinoma, accounts for the vast majority of cases and originates in the small tubes that filter waste from your blood. About 93.6% of people diagnosed when the cancer is still confined to the kidney survive at least five years, but that number drops sharply if the disease has spread to distant organs.
Types of Renal Cell Carcinoma
Not all kidney cancers behave the same way. The tumor’s cell type affects how aggressive it is and which treatments work best. Three subtypes make up more than 90% of all renal cell carcinomas.
Clear cell is by far the most common, representing 70% to 75% of cases. It gets its name from the way the cells look under a microscope: pale and clear. Clear cell tumors tend to respond well to newer targeted and immunotherapy treatments, but they can also be aggressive.
Papillary carcinoma is the second most common subtype at roughly 10% of cases. It grows in finger-like projections inside the tumor and generally carries a somewhat better prognosis than clear cell when caught at a similar stage.
Chromophobe renal cell carcinoma accounts for about 5% of cases, most often appearing in people in their 60s. It tends to grow more slowly and is less likely to spread than clear cell carcinoma.
Risk Factors
Three modifiable risk factors stand out above the rest: high blood pressure, excess body weight, and smoking. Current smokers face roughly 75% higher risk of dying from kidney cancer compared to nonsmokers. The relationship between weight and kidney cancer follows a clear dose-response pattern. Compared to people with a normal BMI, those with a BMI of 30 to 35 have about 40% higher risk, while those with a BMI above 40 have more than double the risk.
High blood pressure raises kidney cancer risk independently of weight. People with systolic readings above 160 have nearly twice the risk of those with readings below 120, and the risk climbs in a step-by-step fashion as blood pressure goes up. Managing blood pressure and maintaining a healthy weight are two of the most concrete things you can do to lower your risk.
Hereditary Kidney Cancer Syndromes
A small percentage of kidney cancers run in families, caused by inherited gene mutations that significantly raise risk. The best-known is von Hippel-Lindau disease (VHL), caused by mutations in the VHL gene. People with VHL can develop tumors in the kidneys, brain, spinal cord, and other organs throughout their lives and typically need regular screening starting at a young age.
Other inherited syndromes include Birt-Hogg-Dubé syndrome, linked to mutations in the FLCN gene, and hereditary papillary renal cancer, caused by changes in the MET gene. A syndrome called hereditary leiomyomatosis and renal cell cancer involves mutations in the FH gene and can produce particularly aggressive kidney tumors. All of these follow an autosomal dominant inheritance pattern, meaning a child has a 50% chance of inheriting the mutation if one parent carries it. If kidney cancer appears in multiple close relatives, especially at younger ages, genetic counseling can help clarify whether a hereditary syndrome is involved.
Symptoms and How It’s Found
Kidney cancer is often called a “silent” disease because early-stage tumors rarely cause noticeable symptoms. Many cases are discovered incidentally, when an imaging scan is done for an unrelated reason.
When symptoms do appear, blood in the urine is the most common, occurring in over 50% of patients. It can be visible to the naked eye or detectable only under a microscope. Flank pain and a palpable mass in the abdomen are other possible signs, but the classic combination of all three typically indicates advanced disease and shows up in fewer than 10% of patients at diagnosis.
Kidney cancer can also produce a range of less obvious effects. Up to 40% of patients develop anemia that isn’t explained by blood loss. Around 20% develop fevers caused by substances the tumor releases. Some patients experience unexplained weight loss, fatigue, or elevated calcium levels. These “whole-body” effects can sometimes appear before any local symptoms in the kidney, which is part of what makes early detection challenging.
How It’s Diagnosed
When a kidney mass is suspected, imaging is the first step. A CT scan with contrast dye is the standard initial test, offering about 85% sensitivity for detecting cancerous masses. MRI performs slightly better, with roughly 91% sensitivity, and is particularly useful for evaluating smaller masses or when CT results are inconclusive. MRI also avoids radiation exposure, which can matter for patients who need repeated scans over time.
Unlike many other cancers, kidney tumors are often treated based on imaging alone, without a biopsy. The combination of a mass’s size, appearance, and how it absorbs contrast dye gives doctors enough information to recommend surgery in most cases. Biopsies are sometimes used for smaller or ambiguous masses, or when a patient isn’t a candidate for surgery.
Stages of Kidney Cancer
Staging describes how far the cancer has grown and whether it has spread. The system uses tumor size and extent as the primary markers.
- Stage I: The tumor is 7 cm or smaller (roughly the size of a tennis ball) and is confined entirely to the kidney.
- Stage II: The tumor is larger than 7 cm but still contained within the kidney.
- Stage III: The cancer has grown into major veins near the kidney, into surrounding fat tissue, or has reached nearby lymph nodes.
- Stage IV: The tumor has broken through the kidney’s outer covering, spread to the adjacent adrenal gland, or metastasized to distant organs like the lungs, bones, or brain.
Stage at diagnosis is the single strongest predictor of outcome. Localized disease (Stages I and II) carries a 93.6% five-year survival rate. Regional spread drops that to 77.6%, and distant metastasis brings it down to 20.3%.
Surgical Treatment
Surgery is the primary treatment for kidney cancer that hasn’t spread to distant sites. The two main options are removing the entire kidney (radical nephrectomy) or removing only the tumor and a margin of healthy tissue while preserving the rest of the organ (partial nephrectomy).
Current guidelines favor partial nephrectomy whenever technically feasible, regardless of tumor size. This approach preserves more kidney function, which lowers the long-term risk of chronic kidney disease and the cardiovascular problems that come with it. For tumors 4 cm or smaller, partial nephrectomy is the standard recommendation. For tumors between 4 and 7 cm, it’s still preferred when the tumor’s location allows it. Radical nephrectomy remains the better option for very large tumors or those in difficult positions that make partial removal unsafe.
For small, slow-growing tumors in older patients or those with other serious health conditions, active surveillance with regular imaging is sometimes chosen instead of immediate surgery.
Treatment for Advanced Disease
The treatment landscape for metastatic kidney cancer has changed dramatically over the past two decades. Traditional chemotherapy has little effect on renal cell carcinoma, but two newer categories of drugs have significantly improved outcomes.
Targeted therapies work by blocking a protein that tumors use to build new blood vessels. By cutting off the tumor’s blood supply, these drugs can slow or shrink the cancer. They are taken as daily pills and were the first major breakthrough in treating advanced kidney cancer.
Immunotherapy drugs called checkpoint inhibitors work differently. They remove the “brakes” that cancer cells put on the immune system, allowing the body to recognize and attack the tumor. In 2015, the checkpoint inhibitor nivolumab became the first immunotherapy approved for kidney cancer that had progressed after initial treatment. By 2018 and 2019, combinations of immunotherapy drugs, or immunotherapy paired with targeted therapy, became the standard first-line treatment for advanced disease. These combinations have produced longer survival and, in some patients, durable remissions lasting years.
The choice between different drug combinations depends on the tumor’s risk profile, the cancer subtype, and how well you tolerate side effects. Immunotherapy side effects can include fatigue, skin rashes, and inflammation in various organs, though most patients manage them well enough to continue treatment.