Symptoms of Kidney Cancer

The signs and symptoms of kidney cancer that alert people and their doctors to its presence have changed dramatically in recent years. In the past, the classic triad of flank pain, blood in the urine, and a mass in the flank were most common. Today, the most common symptoms are anemia, fatigue, weight loss, loss of appetite, and a fever.

In addition, the spread of kidney cancer to other parts of the body (metastatic disease) gives to the first warning signs of the disease (such as a cough or bone pain) in 20 percent to 30 percent of people.

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© Verywell, 2018 

Frequent Symptoms

In the earliest stages of kidney cancer, there are usually few symptoms, and many diagnoses are now made based on lab and imaging studies before symptoms occur.

Anemia

Anemia is currently the most common presenting symptom of kidney cancer, and is present in 20 to 40 percent of people diagnosed. The kidneys make a protein called erythropoietin, which stimulates production of red blood cells in the bone marrow (in a process called erythropoiesis). With kidney cancer, decreased production of this protein results in a low number of red blood cells (anemia).

In contrast, some people may instead have a markedly elevated red blood cell count (erythrocytosis) due to increased production of erythropoietin by kidney cancer cells. This is referred to as a paraneoplastic syndrome—symptoms that occur due to substances or hormones produced by cancer cells (discussed below).

Blood in the Urine

Blood in the urine (hematuria) is a common symptom of kidney cancer, occurring in at least half of people who are diagnosed at some time. That said, only about 10 percent of people now have the classic triad symptoms of blood in the urine, flank pain, and a flank mass at the time of diagnosis, and when these are present, the tumor has usually already spread (metastasized).

Urine may be obviously bloody (referred to as "gross hematuria"), moderate, and causing only a pink tinge to the urine, or may be microscopic so that it is only seen on a urinalysis.

Flank Pain

Pain may occur in the back, side, or abdomen, and can vary from a subtle ache to a sharp, stabbing pain. Pain in the flank that occurs without an obvious injury should always be investigated. Roughly 40 percent of people with kidney cancer experience pain at some time during the course of their disease, but flank pain is becoming less common as the presenting symptom of the disease.

Flank Mass (Back, Side, or Abdomen)

A flank mass (a lump in the side, back, or abdomen) has been noted in up to 45 percent of people with kidney cancer in some studies, though it is less frequently found as an initial symptom than in the past. Any lumps in this region, even if you assume it is one of the common fatty tumors that arise with age, should be looked at by your physician.

Unintentional Weight Loss

Unintentional weight loss is a common symptom of kidney cancer, occurring in around a third of people at the time of diagnosis. It is defined as the loss of 5 percent or more of body weight over a 6 month to 12 month period of time. For example, a loss of 10 pounds in a 200 pounds man over a 6 month period of time, that occurs without a change in diet or exercise, would be considered unexpected or unintentional weight loss.

In addition to kidney cancer, there are a number of serious conditions associated with this symptom, and people should always see their doctor if they lose weight without trying.

Fatigue

Fatigue also occurs in around a third of people diagnosed with kidney cancer. Cancer fatigue, unlike ordinary tiredness, can be profound, and usually worsens over time. It's not the kind of fatigue that improves with a good night of sleep or a good cup of coffee.

Cachexia

Cachexia is a syndrome characterized by weight loss, loss of appetite, and loss of muscle mass. It's thought that cachexia is present in around 30 percent of people diagnosed with kidney cancer. In addition to being a presenting symptom, it is also believed to be the direct cause of death in around 20 percent of people with cancer and deserves your and your doctors' attention if present.

Loss of Appetite

Loss of appetite, with or without cachexia or weight loss, is a common symptom of kidney cancer. People may note that they are just not hungry, or instead, may feel full rapidly while eating.

Fever

A fever (a temperature over 100.4 degrees F) is a common symptom of kidney cancer, occurring in around a third of people at the time of diagnosis. The fever may be continuous, or instead, it may come and go, but occurs without any obvious signs of infection. A fever that does not have an explanation (fever of unknown origin) always deserves a visit to your doctor.

High Blood Pressure

The kidneys produce hormones that play an important role in regulating blood pressure. Persistent high blood pressure may be a symptom of kidney cancer. In turn, persistent high blood pressure can lead to further kidney damage.

Swelling in the Ankles and Legs

The kidneys also play a very important role in regulating fluid balance (and electrolytes) in the body. Kidney cancer (and other kidney diseases) can interfere with this regulation, leading to fluid retention that is observed as swelling in the feet, ankles, and legs.

Flushing

Flushing, or episodes in which the skin becomes red, along with a feeling of warmth (or even burning) of the face, neck, or extremities, is a potential symptom. There are several possible cancerous (malignant) causes of cutaneous flushing, one of which is kidney cancer. Note if this symptom occurs in addition to the others.

Symptoms of Metastases

It's very important to mention the possible symptoms of kidney cancer that has spread (metastasized) to other regions of the body, as symptoms related to these metastases are the presenting symptoms for 20 to 30 percent of people diagnosed with the disease.

Over 30 percent of people have metastases at the time of diagnosis. Kidney cancer most often spreads to the lungs, bones, and brain, and can lead to the following symptoms.

Cough

persistent cough is the most common symptom of cancer spread to the lungs. Other symptoms that may occur include wheezing, coughing up blood, or pain in the chest, shoulder, or back.

Shortness of Breath

Shortness of breath is a common symptom of kidney cancer, both as a symptom of a cancer that has spread to the lungs and due to anemia. Early on, shortness of breath may occur only with activity, and can easily be dismissed as due to being out of shape, weight gain, or aging.

Bone Pain

The bones are the second most common site of kidney cancer metastases (after the lungs). Bone pain from metastases can be severe, and is usually not associated with any form of injury. Sometimes the first sign of cancer is a fracture in the area of weakened bone.

Rare Symptoms

There are a few uncommon but unique symptoms associated with kidney cancer.

Varicocele

varicocele is an enlarged vein (varicose vein) that occurs in the scrotum or testicle. Symptoms may include swelling, pain, and shrinkage of the testicle. Most often occurring on the right side, a varicocele related to kidney cancer does not go away when a person lies down.

Paraneoplastic symptoms

Paraneoplastic syndromes are clusters of symptoms that occur due to the production of hormones or other substances by tumor cells. With kidney cancer, these syndromes may lead to a high calcium level in the blood with symptoms such as nausea and vomiting, weakness, and confusion, an elevated red blood cell count (erythrocytosis), and an increase in liver function tests even when a tumor hasn't spread to the liver (Stauffer syndrome).

Complications

There are a number of complications that may occur due to kidney cancer. At times, these may occur even before diagnosis, but most often are found when the tumor is advanced. They may occur due to the tumor itself, due to treatments of the tumor, or due to metastatic disease.

Keep in mind that most people do not experience all of these complications, and many people do not experience any of these. They are discussed here so that people can be empowered in their health care and aware of potential concerns.

Gross Hematuria

Urine that is frankly bloody occurs less often as a first symptom of kidney cancer, but happens eventually for almost half of people. It can be very frightening to suddenly urinate large amounts of blood, but prompt treatment can usually control the bleeding.

Pleural Effusion

When kidney cancer spreads to the lungs or the lining of the lungs, it may cause the build-up of fluid between the membranes lining the lungs (the pleura). When cancer cells are present, this is referred to as a malignant pleural effusion. Sometimes a large amount of fluid (several liters) accumulates, causing significant shortness of breath.

A procedure called a thoracentesis involves placing a fine needle through the skin on the chest wall and into the pleural cavity to withdraw fluid. Pleural effusions frequently recur and can be treated with either an indwelling pleural catheter (a shunt that allows for continuous drainage of the fluid) or a procedure in which an irritating substance (talc) is placed between the membranes causing them to scar together so that fluid can no longer accumulate (pleurodesis).

Pathological Fractures

Bone pain may be an early symptom of kidney cancer when metastases are present. When cancer infiltrates the bone, it weakens the bone and may result in fractures with minimal or no trauma. These are referred to as pathologic fractures.

When kidney cancer spreads to the lower spine, microfractures in the spine may lead to a collapse of the vertebrae and press on nerve roots, causing spinal cord compression. This may lead to weakness of the legs along with loss of bladder and bowel control, and is a medical emergency.

Bone metastases from kidney cancer tend to be very destructive, requiring careful attention to pain, potential fractures and nerve compression, hypercalcemia (high blood calcium due to a breakdown of bone) and more. Fortunately, there are a variety of treatments available today that can reduce these complications.

High Blood Pressure

As discussed earlier, the kidneys play an important role in regulating blood pressure. Kidney cancer may result in persistent high blood pressure, and sometimes blood pressure that is very difficult to control (malignant hypertension).

Hypercalcemia

An elevated level of calcium may occur in the blood, both due to a paraneoplastic syndrome and due to the breakdown of bone with bone metastases. A high blood calcium level with cancer (hypercalcemia) may lead not only to symptoms such as nausea, but severe muscle weakness, confusion, coma, and even death. That said, it is treatable as long as it is diagnosed.

A High Red Blood Cell Count

A high red blood cell count (erythrocytosis) may occur, even though anemia is common early on with kidney cancer. This occurs due to the production by the cancer cells of the protein that stimulates the bone marrow to produce red blood cells. Excess red blood cells, in turn, can increase the risk of blood clots, heart attacks, and strokes, due to the blood being "thicker" (more viscous).

Liver Insufficiency

Kidney cancer may affect the liver both through the spread of the cancer as well as part of a paraneoplastic syndrome. Since the liver filters the blood, as does the kidney, the combination of liver and kidney dysfunction can result in the accumulation of toxins in the blood, leading to confusion, personality changes, mood changes, and more.

Treatment Complications

Treatments for kidney cancer may include removing part or all of the kidney. This is a major surgical procedure and can result in heart events, a stroke, pulmonary embolism (a clot breaking off in the leg and traveling to the lungs), pneumonia, or injuries during surgery, such as to the liver, spleen, pancreas, or bowel. Infection in the abdomen and bleeding may also occur.

Surgery is more challenging if the tumor extends to the inside of the renal vein, and often requires a surgeon who specializes in vascular disease (such as a heart surgeon) to remove the cancer. Surgery has improved, and complications are much fewer than in the past, especially with the less invasive surgical options now available, such as laparoscopic nephrectomy (removal of the kidney through small incisions in the abdomen and special instruments). If you are undergoing this surgery, trust your healthcare team and voice any concerns you may have.

Renal failure

Since surgery often consists of removing a kidney, or at least part of a kidney, this leaves only one functioning kidney behind. In addition, some of the treatments used for kidney cancer, as well as medications, may place stress on the remaining kidney, leading to kidney failure. If kidney failure occurs, dialysis may be needed (or a kidney transplant if it is an early stage kidney cancer).

When to See Your Doctor

If you have any of the symptoms mentioned above, it's important to see your doctor. Most of the symptoms of kidney cancer have many potential causes, but there are other serious reasons you could be having these symptoms as well.

Symptoms are our body's way of signaling that something is wrong. Rather than fearing and ignoring them, take action to find out why they're occurring so that you can obtain appropriate and timely treatment. Talk to your doctor and ask questions. If you still don't have answers, consider getting a second opinion.

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