Understanding Kidney Cancer

Signs and Symptoms of Kidney Cancer

Last updated and reviewed on June 7, 2026.

A symptom is something you feel or notice yourself, like pain, tiredness, or blood in your urine. A sign is something a doctor can see or measure, like an abnormal result on a lab test or an image from a scan. Kidney cancer can cause both signs and symptoms, but one of the most important things to know is that it often causes no symptoms at all in its early stages. In fact, many kidney cancers are found by accident when a person gets a CT scan or ultrasound for a completely different reason, like abdominal pain or a back injury. This is sometimes called an incidental finding.

What Are the Signs and Symptoms of Kidney Cancer?

Symptoms of kidney cancer can be divided into the more common symptoms that may appear as the tumor grows, and the less common or more serious symptoms that appear if the cancer is advanced or has spread. The earlier kidney cancer is caught, the more treatment options are available and the better the chances of a good outcome. Because early-stage kidney cancer usually causes no symptoms, any new or unexplained urinary or back symptoms are worth reporting to a doctor.

What Are the Most Common Symptoms of Kidney Cancer?

Blood in the urine (hematuria). This is the most recognized symptom of kidney cancer. Blood can make the urine look pink, orange, red, or dark brown, like tea or rust-colored water. Sometimes the amount of blood is so small it cannot be seen with the naked eye and is only found during a routine urine test (urinalysis). Even if the blood comes and goes and seems to stop on its own, it should always be checked by a doctor. Blood in the urine should never be ignored or assumed to be a minor problem.

Pain in the back or side (flank pain). A dull ache or persistent pain on one side of the back, below the ribs, is another common symptom. This pain is caused by the growing tumor pressing on nearby tissues or nerves. Many people first mistake this for a muscle strain or back problem, which is why the diagnosis of kidney cancer is sometimes delayed. If back or side pain does not improve with rest or over-the-counter pain medications, or if it is combined with other urinary symptoms, it is important to see a doctor.

A lump or mass in the side or back. Sometimes a kidney tumor grows large enough to be felt as a lump in the flank area (the side of the body between the lower ribs and the hip). This is more common with larger tumors and is less likely with small, early-stage cancers.

What Are the Less Common Symptoms of Kidney Cancer?

Beyond the classic signs of blood in the urine, flank pain, and a flank mass, kidney cancer can cause a range of less obvious symptoms. These may appear before the typical symptoms, or they may be the only signs of the disease, especially if the tumor is in an area of the kidney that does not easily affect the urinary tract.

• Fatigue (unusual tiredness): Feeling more tired than normal, even with adequate sleep, is common with many cancers. In kidney cancer, fatigue can be caused by anemia (a low red blood cell count) because the kidneys help regulate red blood cell production.
• Unexplained weight loss: Losing weight without trying, especially more than 10 pounds, can be a sign that the body is fighting a serious illness.
• Fever: A persistent, low-grade fever that is not explained by an infection. Some kidney tumors release substances that cause the body to run a fever.
• Anemia: Because kidneys produce a hormone (erythropoietin) that signals the bone marrow to make red blood cells, a tumor can interfere with this process and cause anemia, leading to pallor, fatigue, and shortness of breath.
• High blood pressure (hypertension): The kidneys play a key role in regulating blood pressure. A kidney tumor can disrupt this process and cause blood pressure to rise.
• High calcium in the blood (hypercalcemia): Some kidney cancers release hormones that cause calcium levels in the blood to rise. This can cause symptoms like nausea, confusion, weakness, and constipation.
• Swelling in the legs or ankles (edema): Can occur if the tumor presses on nearby veins or lymph nodes that drain fluid from the legs.
• A cluster of enlarged veins around a testicle (varicocele): In men, a kidney tumor on the left side can block the vein that drains blood from the left testicle, causing a varicocele — a cluster of swollen veins in the scrotum — that appears suddenly.

These symptoms are called paraneoplastic syndromes when they are caused by the tumor releasing substances that affect other parts of the body, rather than by direct tumor invasion. About 20% of people with kidney cancer experience some form of paraneoplastic syndrome.

What Are the Symptoms of Advanced (Metastatic) Kidney Cancer?

When kidney cancer has spread beyond the kidney to other parts of the body, it is called metastatic or advanced kidney cancer. At this stage, symptoms can be more widespread and more serious. Kidney cancer most commonly spreads to the lungs, bones, brain, liver, and adrenal glands. The symptoms a person experiences depend heavily on which organs are affected.

• Lung metastases can cause a persistent cough, shortness of breath, coughing up blood, or chest pain.
• Bone metastases can cause deep, aching bone pain, especially in the spine, hips, or ribs. The bones may also become brittle and break more easily.
• Brain metastases can cause headaches, dizziness, vision changes, weakness on one side of the body, or seizures.
• Liver metastases can cause pain in the upper right abdomen, jaundice (yellowing of the skin and eyes), or a swollen belly.
• General symptoms of advanced cancer include significant unintentional weight loss, severe fatigue, loss of appetite, and feeling generally unwell.

If you experience any of these symptoms, especially in combination, it is important to talk to your doctor promptly. Many of these symptoms have other explanations, but when several occur together, they deserve careful evaluation.

 Sources:

1. Kidney Cancer Association. Symptoms of Kidney Cancer. https://www.kidneycancer.org/knowledge/learn/kidney-cancer-symptoms/