Metastatic renal cell carcinoma is kidney cancer that has spread beyond the original tumor to other parts of the body. While this advanced stage presents serious challenges, understanding the diagnostic process can help patients and their families navigate the journey with greater confidence and clarity.

Introduction: Who Should Undergo Diagnostics

Diagnosing metastatic renal cell carcinoma often begins unexpectedly. In many cases, kidney tumors are discovered by accident when doctors are looking for something else entirely. About half of kidney tumors are found during a CT scan (a detailed imaging test that uses X-rays) or regular X-ray performed for unrelated reasons. This type of discovery is sometimes called an incidental finding.^[6]

Some people may notice symptoms that prompt them to seek medical attention. These warning signs can include blood in the urine, which is one of the most common symptoms of kidney cancer. Other symptoms might include persistent pain in the back or side that doesn’t go away, a lump in the belly area, unexplained weight loss, fever that comes and goes, night sweats severe enough to require changing clothes or sheets, and general feelings of tiredness or not wanting to eat much. If the cancer has already spread to other parts of the body, symptoms may appear in those locations too. For example, if cancer has reached the bones, it might cause bone pain. If it has traveled to the lungs, it could lead to coughing or difficulty breathing.^[1][2]

Anyone experiencing these symptoms should see their doctor promptly. However, it’s important to understand that in its early stages, kidney cancer typically has no symptoms at all. This is why many tumors go undetected until they are found by chance or have already grown larger or spread.^[11]

People with certain risk factors should be particularly aware of the importance of regular medical checkups. Risk factors for kidney cancer include smoking tobacco, misusing certain pain medicines over a long time (including some over-the-counter medications), having excess body weight, having high blood pressure, and having a family history of kidney cancer. Certain genetic conditions also increase risk, such as von Hippel-Lindau disease or hereditary papillary renal cancer.^[3]

Diagnostic Methods for Identifying Metastatic Renal Cell Carcinoma

When doctors suspect kidney cancer, they use a variety of tests to confirm the diagnosis, determine the size and location of the tumor, and find out if cancer cells have spread to other parts of the body. The diagnostic process is thorough and may involve several different types of examinations and imaging studies.^[6]

Physical Examination and Medical History

The diagnostic journey typically begins with a physical exam to check overall health. During this exam, your doctor will check vital signs like blood pressure, temperature, weight, and pulse. These basic measurements help doctors understand your general health status. Your healthcare team will also take a complete medical and family history. They’ll ask about medicines you take, any other health conditions you have, and results of previous health tests. They’ll want to know if any family members have had kidney cancer or other diseases, since some kidney cancers can run in families.^[6]

Blood Tests

Blood tests are an essential part of diagnosing metastatic renal cell carcinoma. Your healthcare team will take samples of your blood to check how well your kidneys are working and assess your overall health. A Complete Blood Count (CBC) test measures the number of different types of cells in your blood, such as red blood cells, white blood cells, and platelets. Blood chemistry tests look at how well your liver and kidneys are working, and they check levels of important substances like sodium and potassium in your body. These tests can also reveal certain abnormalities that may suggest cancer has spread.^[6]

Urinalysis

A urinalysis is a test of your urine (pee) that looks for blood, extra proteins, or signs of infection. Blood in the urine is one of the most common signs of kidney cancer, although it can also be caused by other conditions. This simple test provides valuable information about what’s happening in your kidneys and urinary system.^[6]

Imaging Tests

Imaging tests are crucial for diagnosing metastatic renal cell carcinoma and determining how far the cancer has spread. These tests create detailed pictures of the inside of your body, allowing doctors to see tumors and assess whether cancer has reached other organs.

A Computed Tomography (CT) scan is one of the most important imaging tests for kidney cancer. This test uses X-rays to create detailed, cross-sectional images of certain areas of your body. Doctors will scan your abdomen (belly) and pelvis to show your kidneys and nearby areas, which helps them see if the cancer has spread. Before your scan, you may receive contrast material—a substance that you either drink or that is injected into a vein—to improve the quality of the images. If you’ve ever had a reaction to contrast material or iodine in the past, it’s important to tell your doctor.^[6]

Magnetic Resonance Imaging (MRI) uses radio waves and powerful magnets to take detailed pictures of your body. An MRI is particularly useful for checking if kidney cancer has spread to major blood vessels or the brain. During an MRI, you’ll need to lie still in an enclosed space for 15 to 90 minutes. If you feel anxious about being in enclosed spaces, tell your doctor beforehand—they may have options to make you more comfortable. If you have any metal in your body, such as a hip replacement or pacemaker, you must inform your doctor, as these can interfere with the MRI.^[6]

A chest X-ray is an imaging test used to see if the cancer has spread to your lungs. The lungs are one of the most common places where kidney cancer spreads. If something suspicious shows up on the X-ray, your doctor may order a CT scan of your chest for a more detailed look.^[6]

A bone scan is an imaging test that can show if cancer has spread to your bones. Before the scan, a small amount of radioactive material is injected into a vein. It takes about three hours for this material to travel through your blood and into your bones. Then doctors use a special camera to take pictures that show where the radioactive material has collected in your bones, which can indicate areas where cancer may have spread.^[6]

Biopsy

A biopsy is a procedure where a doctor removes a small sample of tissue from the tumor so it can be examined under a microscope. This is the only way to definitively confirm whether a growth is cancerous. During a biopsy for kidney cancer, a doctor may use a needle to remove tissue, often guided by imaging technology to ensure they’re sampling the right area. While biopsies are not always necessary for kidney cancer diagnosis—sometimes imaging tests provide enough information—they can be very helpful in certain situations, especially when doctors need to determine the exact type of kidney cancer.^[6]

Distinguishing Metastatic Renal Cell Carcinoma from Other Conditions

Metastatic renal cell carcinoma is kidney cancer that has spread beyond the lymph nodes to other areas of the body such as the lungs or bones. It’s also called stage IV kidney cancer. Patients with renal cell cancer develop metastatic spread in approximately 33% of cases. Common sites where the cancer spreads include the lung, liver, bone, brain, and adrenal gland. More than one organ system is often involved in the spreading process.^[4][5]

Understanding how cancer spreads helps doctors know where to look. As a kidney tumor grows, it spreads into fat or major blood vessels around the kidney. It may also creep into the adrenal gland, which sits right on top of the organ. From there, cancer cells can spread farther through your blood or lymph system. The lymph system is a network that runs throughout your body, much like your blood vessels, and helps you fight disease. But cancer cells that get into lymph nodes can hitch a ride to other organs. Cancer cells that enter blood vessels can travel to many body parts through your veins and arteries.^[1]

Because kidney cancer often has no symptoms early on, it can spread before anyone even knows it’s there. If the cancer is found early but treatment doesn’t eliminate all the cancer cells, it can come back in the kidney or somewhere else in the body.^[1]

Diagnostics for Clinical Trial Qualification

When patients with metastatic renal cell carcinoma are being considered for clinical trials, additional diagnostic tests and assessments may be required. Clinical trials are research studies that test new treatments or combinations of treatments to see if they work better than current options.

Risk Stratification

A critical first step in determining eligibility for certain clinical trials and therapeutic decision-making for patients who require systemic therapy for advanced or metastatic renal cell carcinoma is risk stratification. This means categorizing patients based on how aggressive their cancer is likely to be and how well they might respond to treatment.^[7]

The most widely used tool for risk stratification is based on information from the International Metastatic Renal Cell Carcinoma Database Consortium (IMDC). This classification uses six specific criteria to predict patient outcomes. The IMDC criteria include: whether less than one year has passed from the time of diagnosis to when systemic therapy begins; whether the patient’s performance status (ability to carry out daily activities) is reduced; whether hemoglobin (a protein in red blood cells) is below the lower limit of normal; whether corrected calcium is above the upper limit of normal; whether neutrophils (a type of white blood cell) are above the upper limit of normal; and whether platelets (blood cells that help with clotting) are above the upper limit of normal.^[7]

Based on how many of these criteria a patient meets, they are classified into one of three risk groups: favorable risk (0 criteria), intermediate risk (1-2 criteria), or poor risk (3-6 criteria). This classification is not only a tool to estimate survival but also helps determine eligibility for certain treatments and clinical trials. Many clinical trials specifically enroll patients based on their IMDC risk category.^[7]

Performance Status Assessment

Clinical trials often have specific requirements regarding a patient’s performance status. This is a measure of how well you can perform ordinary daily activities and how the cancer and its symptoms are affecting your daily life. One common measurement is the Karnofsky Performance Status, which is part of the IMDC criteria. A lower performance status may affect eligibility for certain trials, as many studies require patients to be well enough to tolerate experimental treatments.^[7]

Multidisciplinary Evaluation

Patients being considered for clinical trials typically undergo evaluation by a multidisciplinary team. This team might include oncologists (cancer doctors), urologists (doctors who specialize in urinary system conditions), nurses with special training in cancer care, dietitians, and pharmacists. A multidisciplinary team approach ensures that all aspects of a patient’s health are considered when determining whether they’re a good candidate for a clinical trial.^[7]

The team will review all diagnostic test results, including imaging studies, blood tests, and biopsy results if available. They’ll also consider the patient’s medical history, current medications, other health conditions, and personal circumstances. This comprehensive evaluation helps ensure that patients enrolled in clinical trials are likely to benefit and can safely participate in the research.

Baseline Testing

Before enrolling in a clinical trial, patients typically need comprehensive baseline testing. This establishes a starting point that researchers can use to measure how well the experimental treatment works. Baseline testing usually includes repeated imaging studies, detailed blood work, kidney function tests, and assessments of any symptoms or side effects the patient is experiencing. These baseline measurements are then repeated at regular intervals throughout the trial to track progress and detect any changes.