Renal cancer – Diagnostics – Overview of Information and Clinical Research

Finding kidney cancer early can make a big difference in treatment success. Because this disease often doesn’t cause symptoms in its early stages, knowing when to get checked and understanding the tests available is important for anyone at risk.

Introduction: Who Should Undergo Diagnostics

Kidney cancer, also called renal cancer or renal cell carcinoma, is one of the most common cancers affecting adults. The challenge with this disease is that it often develops quietly, without obvious warning signs in the beginning. More than half of all people with kidney cancer have no symptoms at all when their tumor is discovered. This means many cases are found by accident when someone has a scan for a completely different reason^[1]^[2].

Because of this silent nature, certain groups of people should be more alert about getting diagnostic tests. If you notice blood in your urine (which doctors call hematuria), this is an important warning sign that needs immediate attention. Even if it only happens once or the blood is barely visible, you should see a doctor^[2]^[9]. Other symptoms that should prompt you to seek medical care include pain in your side or lower back that isn’t from an injury, a lump or mass you can feel in your abdomen or side, unexplained weight loss, persistent tiredness, fever that keeps coming back without being caused by a cold or flu, and loss of appetite^[1]^[2].

People with certain risk factors should also be more vigilant. If you smoke tobacco, are significantly overweight, have high blood pressure, undergo long-term dialysis, or have family members who had kidney cancer, your risk is higher^[1]^[9]. Workers exposed to a chemical called trichloroethylene in their jobs—such as mechanics, dry cleaners, and certain manufacturing workers—face increased risk as well^[5]^[9]. People with inherited conditions like von Hippel-Lindau disease need regular monitoring because they have a much higher chance of developing kidney cancer^[5]^[9].

⚠️ Important

Kidney cancer is most commonly diagnosed in people between ages 65 and 74, though it can occur at any age. Men develop it about twice as often as women. The disease is also more common in Native American and Black populations. If you’re older than 35 and notice any blood in your urine—even without pain—you should have imaging tests done to check your kidneys^[2]^[19].

Diagnostic Methods for Identifying Kidney Cancer

Physical Examination and Medical History

When you first visit your doctor with concerns about kidney cancer, they will begin with a thorough medical history and physical examination^[11]. During the physical exam, your doctor will check for lumps or masses in your abdomen and kidney area. They will also look for signs like swelling in your ankles or legs, check your blood pressure, and feel your lymph nodes. This initial assessment helps guide what tests should come next.

Laboratory Tests

Blood and urine tests are fundamental parts of diagnosing kidney cancer. A urinalysis examines your urine under a microscope to look for blood, which may not always be visible to the naked eye^[11]. Your doctor will also order blood tests to check how well your kidneys are working, measure red blood cell counts to look for anemia, and check calcium levels in your blood—high calcium can sometimes indicate kidney cancer^[2]^[11].

These laboratory tests cannot confirm kidney cancer on their own, but they provide important clues. If your blood shows decreased kidney function or your urine contains blood, your doctor will recommend imaging tests to see what’s happening inside your kidneys.

Imaging Tests

Imaging tests are the most important tools for detecting kidney cancer. The gold standard is a computed tomography scan, commonly called a CT scan. When diagnosing kidney masses, doctors prefer a special type called contrast-enhanced, triple-phase CT^[19]. This test involves injecting a contrast dye into your vein, then taking images at three different time points as the dye moves through your body. This helps doctors see the difference between healthy kidney tissue and cancerous tumors.

Magnetic resonance imaging (MRI) is another powerful imaging tool that uses magnets and radio waves instead of radiation to create detailed pictures of your kidneys^[11]. MRI scans are particularly helpful when doctors need to see how a tumor relates to blood vessels or if someone cannot have the contrast dye used in CT scans because of kidney problems or allergies.

Ultrasound is often used as a first imaging test because it’s quick, doesn’t use radiation, and can clearly show whether a kidney mass is solid or filled with fluid^[11]. However, ultrasound alone usually isn’t enough to fully diagnose kidney cancer. If an ultrasound finds something suspicious, your doctor will likely order a CT or MRI scan for more detailed information.

An intravenous pyelogram (IVP) is an older test where contrast dye is injected into a vein and X-rays are taken as the dye travels through your kidneys, ureters, and bladder^[10]. This test can detect tumors, kidney stones, and blockages. While not used as commonly today because CT scans provide more information, it’s still performed in some situations.

Classification of Kidney Masses

When imaging tests find a cyst—a fluid-filled sac in the kidney—doctors use a system called the Bosniak classification to describe how worrisome it looks^[19]. Simple cysts are harmless and need no treatment. More complex cysts are rated from category I (definitely benign) to category IV (very likely to be cancer). If you have a Bosniak category III or IV cyst, or certain category IIF cysts, your doctor will recommend seeing a urologist for further evaluation and possible treatment.

Biopsy

Unlike many other cancers, kidney cancer often doesn’t require a biopsy—taking a small sample of tissue for examination under a microscope—before treatment^[11]. This is because imaging tests can usually provide enough information to make treatment decisions. However, biopsies are sometimes performed when the diagnosis is uncertain, when a tumor is very small, or when a doctor needs to know the exact type of kidney cancer before choosing systemic treatment for advanced disease^[5].

When a biopsy is done, it’s usually performed as a needle biopsy, where a thin needle is inserted through your skin into the tumor while using ultrasound or CT imaging for guidance. The tissue sample is then examined by a specialist called a pathologist, who can identify cancer cells and determine what type of kidney cancer is present.

Additional Tests for Cancer Spread

If imaging shows you likely have kidney cancer, your doctor will order tests to see if the cancer has spread beyond the kidney. A chest X-ray or CT scan of the chest checks for spread to the lungs^[11]. A bone scan might be ordered if you have bone pain or elevated calcium levels in your blood, as these could indicate the cancer has spread to bones^[5].

For more advanced cases, a positron emission tomography scan (PET scan) might be used. This test involves injecting a small amount of radioactive sugar into your vein. Cancer cells, which use more energy than normal cells, absorb more of this sugar and show up as bright spots on the scan^[11].

Diagnostics for Clinical Trial Qualification

Clinical trials are research studies that test new treatments or combinations of treatments for kidney cancer. If you’re considering joining a clinical trial, you’ll need to undergo specific diagnostic tests to determine if you’re eligible. These tests help researchers ensure the study includes the right patients and that the experimental treatment is safe for you^[12].

Imaging Requirements

Most kidney cancer clinical trials require recent imaging scans—usually a CT or MRI—performed within a few weeks before you enroll. These baseline images document the size and location of all tumors in your body. During the trial, you’ll have repeat scans at regular intervals so researchers can measure whether the experimental treatment is shrinking your tumors. The imaging must be done following specific protocols so that all patients in the study have comparable scans.

Tissue Analysis and Biomarkers

Many modern clinical trials require tissue from your tumor for analysis. If you had surgery to remove your kidney or part of it, stored tissue from that operation might be tested. Otherwise, you may need a fresh biopsy. Researchers examine the tissue to identify the exact type of kidney cancer you have and to look for specific proteins or genetic changes called biomarkers^[5].

For example, most kidney cancer cells have changes in a gene called VHL, which causes production of a protein called vascular endothelial growth factor (VEGF) that helps tumors grow new blood vessels^[5]^[16]. Some clinical trials test drugs that specifically block VEGF, so they only enroll patients whose tumors have this characteristic. Other trials might look for different biomarkers depending on what treatment is being studied.

Blood and Organ Function Tests

Clinical trials have strict requirements about your overall health and how well your organs are working. You’ll need blood tests to check your kidney function, liver function, blood cell counts, and other factors^[12]. These tests ensure the experimental treatment won’t be too dangerous for you if your organs aren’t working well enough to handle it. For instance, if a trial is testing a drug that’s processed by the kidneys, you need sufficient remaining kidney function to safely clear the drug from your body.

You might also need an electrocardiogram (ECG or EKG) to check your heart’s electrical activity, or an echocardiogram to see how well your heart is pumping. Some cancer treatments can affect the heart, so trials testing these medications only accept patients whose hearts are healthy enough.

Performance Status Assessment

Clinical trials assess your overall physical condition using scoring systems like the ECOG performance status or Karnofsky performance score. These simple scales measure how well you can perform daily activities. For example, a score might indicate whether you can work and be fully active, need to spend some time resting during the day, or require help with self-care. Many trials only accept patients with good performance status because they’re more likely to tolerate intensive treatments.

Staging Determination

Your cancer must be staged—meaning doctors determine how far it has spread—to qualify for most clinical trials. Staging combines information from physical exams, imaging tests, and sometimes surgical findings^[12]. Some trials only accept patients with early-stage, localized disease, while others specifically study advanced or metastatic cancer that has spread to other organs. The staging information from your diagnostic tests determines which trials might be appropriate for you.

⚠️ Important

If you’re interested in clinical trials, talk with your medical team early in your treatment journey. Some trials are only available to patients who haven’t yet received certain treatments, while others are specifically for people whose cancer has progressed despite previous therapy. Your doctors can help identify trials that match your situation and ensure you have the proper diagnostic tests completed^[13].

Prognosis and Survival Rate

Prognosis

The outlook for people with kidney cancer depends heavily on several factors, with the most important being the stage at which the cancer is discovered. Early detection makes an enormous difference in outcomes. The cancer’s stage tells doctors how large the tumor is and whether it has spread beyond the kidney to nearby structures or distant parts of the body. People whose kidney cancer is found while still confined to the kidney generally have excellent prospects, while those with cancer that has spread to other organs face greater challenges^[9]^[12].

Your functional status—meaning how well you can carry out normal daily activities—also affects prognosis. People who remain active and can take care of themselves tend to respond better to treatment and have better outcomes than those who are weak or require significant assistance^[5]. Other factors that influence prognosis include the specific type and grade of kidney cancer you have (how abnormal the cancer cells look under a microscope), your age and overall health, how well your remaining kidney is functioning, and whether you have other medical conditions like diabetes or heart disease.

It’s important to understand that kidney cancer is highly treatable, especially when caught early. Even for people with more advanced disease, new treatments developed in recent years have significantly improved outcomes and extended survival^[1]^[16]. Treatments targeting specific proteins on cancer cells and therapies that help your immune system fight cancer have changed the landscape dramatically. Many people with metastatic kidney cancer now live for years with good quality of life, something that wasn’t possible just a decade or two ago.

Survival rate

Survival statistics provide a general picture of outcomes, but remember that every person’s situation is unique. These numbers come from large groups of patients and represent averages—your individual outcome may be better or worse depending on your specific circumstances. When kidney cancer is diagnosed while still localized to the kidney, the five-year survival rate is approximately 93 percent, meaning that 93 out of 100 people are still alive five years after diagnosis^[16]. This high survival rate reflects both the effectiveness of surgery to remove kidney tumors and the fact that many people can live normal, healthy lives with one kidney or even part of a kidney remaining^[26].

When kidney cancer has spread to nearby lymph nodes or structures around the kidney but hasn’t reached distant organs (called regional spread), survival rates decrease but remain substantial. The five-year survival rate for kidney cancer that has metastasized to distant parts of the body—such as the lungs, bones, liver, or brain—is approximately 12 percent^[16]. While this number might seem discouraging, it’s important to know that many of the newer treatments weren’t available when these statistics were calculated, and outcomes are improving as treatment options expand.

These survival rates are based on how far the cancer has spread, but other factors matter too. The type of kidney cancer affects outcomes—clear cell kidney cancer, which accounts for about 70 to 80 percent of cases, tends to be discovered at more advanced stages and has different survival patterns than papillary or chromophobe types^[5]^[8]. Your response to treatment is also crucial. Some people’s cancers respond remarkably well to targeted therapies or immunotherapy, leading to long-term control of the disease even when it has spread.

#1 Clinical Trials Search in Europe