Kidney cancer can be one of several different diseases. The most common type is renal cell carcinoma.
Kidney cancer occurs when cells in one or both kidneys begin to spin out of control. Eventually, these cells become lumps called tumors. As cancer progresses, it can spread to other parts of the body.
This article discusses kidney cancer, its types, symptoms, and causes. It also looks at how kidney cancer is diagnosed and treated.
Kidney Anatomy and Function
The kidneys are two bean-shaped organs. Each is the size of a small fist. They are located behind the abdominal organs, one on each side of the spine.
Some people have only one kidney. This can be the result of a birth defect or disease. As long as the kidneys are functioning properly, you can live just fine with just one kidney.
The kidneys filter impurities and remove excess minerals, salts and water from the blood. These are excreted through urine. Every day, about 45 gallons of blood are filtered through your kidneys. This produces about 1 to 2 quarts of urine. Urine enters the bladder through tubes called ureters, where it is held until you urinate.
The filtering unit in the kidney is called Nephron. There are over a million of these units in each kidney.Inside the nephron, there is a structure called glomerulus act as a filter. Another structure called a tubule removes waste and returns important substances to your blood.
Types of Kidney Cancer
There are several types of kidney cancer, including:
- Renal cell carcinoma: This is by far the most common form of kidney cancer. It accounts for nine out of ten cases.
- Transitional cell carcinoma: About 7 percent of kidney cancers are transitional cell carcinomas. These come from the same types of cells associated with bladder cancer. Treatment of transitional cell carcinoma is more like bladder cancer than renal cell carcinoma.
- Wilm’s tumor: Wilm’s tumor is a cancer that usually develops in childhood. It is relatively common in childhood cancers.
- Renal sarcoma: Renal sarcoma is a rare tumor. It starts in the connective tissue of the kidneys.
Because renal cell carcinoma is the most common type, most of the information below is for this type.
Renal cell carcinoma is thought to arise from the tubules in the nephron.
kidney cancer symptoms
Kidney cancer symptoms usually don’t appear until the disease has progressed. When symptoms occur, they may include:
- blood in the urine, either after urination or seen under a microscope
- Lump on one side of the abdomen (side bump)
- Pain in the side or lower back (side area)
- Unintentional weight loss
What are the signs and symptoms of kidney cancer?
What causes kidney cancer?
The exact cause of kidney cancer is unknown. However, researchers have identified several risk factors for kidney cancer. Some of these include:
- Age: The risk of kidney cancer increases with age. Most renal cell carcinomas occur in people over the age of 40. Wilm’s tumor is more common in children.
- Gender: Kidney cancer is more common in men than in women.
- Race: Kidney cancer is more common among blacks and Native Americans.
- Smoking: People who smoke have an increased risk of kidney cancer.
- Occupation: Workplace exposure to certain substances, such as asbestos and benzene, increases risk.
- Family history: A family history of kidney cancer or certain genetic syndromes increases risk.
- Medications: The use of certain medications, such as calcium channel blockers, can increase the risk of kidney cancer.
What is the cause of kidney cancer? Who is at risk?
How to Diagnose Kidney Cancer
Historically, the most common symptoms of kidney cancer have been:
- Low back pain (side and lower back pain)
- abdominal mass
- blood in the urine
Today, kidney cancer is often found during imaging tests for another disease, such as X-rays, CT scans, or MRIs.
When a health care provider suspects kidney cancer, an ultrasound is usually the first test ordered. Ultrasound uses sound waves to create images. It can differentiate between solid tumors and cysts.
A CT scan is probably the most useful imaging test. This test combines multiple X-ray images into a 3-dimensional image of the internal structure of the body. It may include contrast media given by injection. Contrast is a dye that makes internal structures show up better in an image.
CT scans can be used to detect and stage kidney cancer. Staging is the process of determining how big the tumor is and whether it has spread.
Some people cannot have CT scans. This may be due to an allergy to the contrast medium or poor kidney function. People who cannot have a CT scan may get an MRI. MRI uses magnetic imaging instead of X-rays. MRI is also helpful if the tumor is thought to have spread into a vein near the kidney.
Biopsies allow pathologists to look under the microscope for cancer cells. This is very helpful in guiding the treatment of targeted therapy. Samples are often obtained during surgery to treat cancer rather than during diagnosis.
Unlike many tumors, a biopsy is not always required to diagnose kidney cancer.
If cancer is found, more tests may be needed to determine if it has spread to nearby tissues or organs.
Kidney cancer is staged by measuring the size of the tumor within the kidney structure. Your healthcare provider will also look for evidence of spread to nearby tissues or distant areas of the body.
Kidney Cancer Staging
- Stage 1 tumors are confined to the renal cortex. This is the periphery of the kidneys.
- Stage 2 tumors are larger but still confined to the kidney.
- Stage 3 tumors have spread to nearby blood vessels.
- Stage 4 tumors have spread beyond the outer layers of the kidney and may also spread to nearby organs.
What tests are performed to detect kidney cancer?
Kidney cancer is somewhat unique. This is because even advanced tumors can be operated on. Targeted therapy and immunotherapy drugs can also be used. Chemotherapy and radiation therapy work less well than some other cancers.
Treatment for kidney cancer depends on the stage of the disease and many other factors. For example, your general health and the location of cancer in your kidneys will help guide treatment decisions.
Most kidney cancer patients will undergo some kind of surgery. People with early-stage kidney cancer are the best candidates for surgery. However, kidney cancer is one of the few solid tumors for which surgery may be beneficial even for advanced metastatic disease (stage 4).
Surgery is the treatment of choice for most kidney cancers. However, for some patients, this can be difficult. Very elderly people or people with several serious medical conditions may not be able to tolerate surgery.In these cases, treatments such as cryosurgery (cryosurgery) or radiofrequency ablation (burning), may be an option.
Some targeted therapy drugs have been approved for some patients with advanced kidney cancer. These drugs block and stop the growth and spread of malignant cells. They do this by directly interfering with pathways involved in cancer growth. They also prevent the growth of blood vessels needed to supply the tumor with nutrients.
These drugs have different side effects than chemotherapy. These drugs are also generally better tolerated.
Immunotherapy, also known as biological therapy, is a newer form of cancer treatment. It fights cancer cells by stimulating the body’s own immune system. Several different classes of these drugs have been found to be effective against kidney cancer.
Clinical trials are also an option
There are also many clinical trials underway. These trials are looking for newer or better treatments for kidney cancer. Some of these trials now offer treatments that may improve outcomes.
Remember, every treatment we currently have for cancer has been studied in clinical trials. Currently, kidney cancer treatment and survival rates are improving.
Radiation therapy is not often used to treat kidney cancer. It can be used “palliatively” to relieve discomfort that can occur when cancer spreads. Chemotherapy has a limited effect on renal cell carcinoma.
Palliative care is care focused on treating cancer symptoms and improving quality of life. This is very important, even for people whose early-stage tumors may be curable.
What are the treatments for kidney cancer?
There are several types of kidney cancer. The most common is renal cell carcinoma. Symptoms of kidney cancer can include blood in the urine, side or lower back pain, and unintentional weight loss. Kidney cancer is sometimes found on imaging scans for other conditions.
Kidney cancer is usually treated with surgery, even in later stages. It can also be treated with targeted therapy drugs.
It’s important to know the potential symptoms of kidney cancer and your risk factors. This can help ensure that if you do have kidney cancer, it will be caught at an early stage. There are many treatment options for kidney cancer.
That said, an ounce of prevention is worth a pound of cure. There are many things you can do to reduce your risk. Smoking is an important risk factor for kidney cancer. If you smoke, quit smoking. If you don’t, don’t start. The risk does decrease when you exit, so it’s never too late. There are also many reasons to quit smoking after a cancer diagnosis.
Take the time to understand any chemicals or other substances you are exposed to at work. If you do come into contact with these chemicals in the workplace, be sure to follow the recommended precautions. In the end, it’s important to eat a healthy diet and maintain a healthy weight. Obesity is a risk factor for many cancers, not just kidney cancer.
What are the signs and symptoms of kidney cancer?