Kidney Cancer or renal cancer begins when healthy cells in one or both kidneys change and grow out of control, forming a mass called a kidney cortical tumor. Tumors can be malignant, indolent, or benign.
Most people have two kidneys which are located above the waist on either side of the spine. The kidneys filter the blood to remove wastes, excess minerals and salts, and extra fluids. Every day, the kidneys filter about 200 liters of blood to produce two liters of urine. The kidneys also produce hormones that help control blood pressure, red blood cell production, and other bodily functions.
Malignant tumors are cancerous, meaning they can grow and spread to other parts of the body. Indolent tumors are also cancerous, but they rarely spread to other parts of the body. Benign tumors mean the tumor can grow but will not spread.
Types of Kidney Cancer
Renal cell carcinoma
Renal cell carcinoma (RCC), also known as renal cell cancer or renal cell adenocarcinoma, is the most common type of kidney cancer. About 9 out of 10 kidney cancers are renal cell carcinoma.
Although RCC usually grows as a single tumor within the kidney, sometimes there are two or more tumors in one kidney or even tumors in both kidneys at once.
There are several subtypes of RCC, mainly based on the appearance of cancer cells in the laboratory. Knowing the RCC subtype can be a factor in deciding on treatment and can help doctors determine whether cancer may be caused by an inherited genetic syndrome.
Clear cell subtype of renal cell carcinoma
The subtype of clear cell renal cell carcinoma (clear cell renal cell carcinoma) is the most common form of renal cell carcinoma. About 7 in 10 people with RCC have this type of cancer. When viewed in the lab, the cells that make up the clear cell subtype of renal cell carcinoma look very pale or clear.
Non-clear cell renal cell carcinoma
Papillary renal cell carcinoma: This is the second most common subtype. About 1 in 10 RCCs are of this type. These cancers form little finger-like projections (called papillae) in some, if not most, tumors. Some doctors call these cancers chromophilic because the cells take up a certain dye and look pink when viewed under a microscope.
Chromophobe renal cell carcinoma: This subtype accounts for about 5 percent (5 cases in 100) of RCC. These cancer cells are also pale, like clear cells, but much larger and have certain other features that can be recognized when looked at very closely.
Rare types of renal cell carcinoma: These subtypes are extremely rare, each making up less than 1 percent of the RCC:
- Collecting duct RCC.
- Multilocular cystic RCC.
- Medullary carcinoma.
- Mucinous tubular and spindle cell carcinoma.
- Neuroblastoma-associated RCC.
- Unclassified renal cell carcinoma: Rarely, renal cell cancer is labeled “unclassified” because its appearance does not fit into other categories or because more than one type of cancer cell is present.
Other types of kidney cancer
Other types of kidney cancer include transitional cell carcinoma, Wilms tumor, and renal sarcoma.
- Transitional cell carcinoma (TCC): Out of every 100 cancers in the kidney, about 5 to 10 are TCC, which is also known as urothelial carcinoma. This type doesn’t start in the kidney, but in the lining of the renal pelvis (where the ureter meets the kidney). This layer is made up of cells called transitional cells that look like the cells that line the ureters and bladder. Cancers that develop from these cells look like other urothelial carcinomas, such as bladder cancer, when viewed closely in the laboratory. Like bladder cancer, it is often associated with smoking and exposure to certain cancer-causing chemicals in the workplace. People with TCC often have the same signs and symptoms as people with kidney cell cancer, namely blood in the urine and sometimes back pain.
- Wilms tumor (nephroblastoma): Wilms tumor almost always occurs in children, very rarely in adults.
- Kidney sarcoma: Kidney sarcoma is a rare type of kidney cancer that starts in the blood vessels or connective tissue of the kidney. This type contributes to less than 1 percent of all cases of kidney cancer.
Reason Kidney Cancer
As explained on the National Health Service page, the exact cause of kidney cancer is unknown. However, experts have found a few things that can increase your risk of developing it. This includes:
- Older age: The risk of developing kidney cancer increases with age.
- Smoking: Smokers have a greater risk of developing kidney cancer than non-smokers. The risk decreases after stopping.
- Obesity: People who are obese have a higher risk of developing kidney cancer than people who are considered to be at a healthy weight.
- High blood pressure: High blood pressure (hypertension) increases the risk of kidney cancer.
- Treatment for kidney failure: People who receive long-term dialysis to treat chronic kidney failure have a greater risk of developing kidney cancer.
- Certain inherited syndromes: Being born with certain inherited syndromes may have an increased risk of kidney cancer, such as those with von Hippel-Lindau disease, Birt-Hogg-Dube syndrome, tuberous sclerosis complex, hereditary papillary renal cell carcinoma, or familial kidney cancer.
- Family history of kidney cancer: The risk of kidney cancer is higher if close family members have the disease.
Often, kidney cancer is found when a person has an imaging test, such as an ultrasound, MRI, or CT for another reason. In its early stages, kidney cancer is painless. Hence, symptoms of the disease usually appear when the tumor grows large and begins to invade the surrounding organs, as reported by the American Society of Clinical Oncology.
People with kidney cancer may experience symptoms or signs. Symptoms are changes that can be felt in the body. A sign is a change in something that is being measured, such as by taking your blood pressure or doing a lab test. Symptoms and signs can help describe a medical problem. Sometimes, people with kidney cancer do not have the symptoms and signs described below. In other cases, the cause of the symptoms or signs may be a noncancerous medical condition.
- Blood in urine.
- Pain or pressure in the waist or back.
- A mass or lump on the side or back.
- Swelling of the ankles and feet.
- High blood pressure.
- Loss of appetite.
- Unexplained weight loss.
- Fever that keeps coming back and is not due to a cold, flu, or other infection.
- In the testicle, rapid development of a cluster of enlarged veins (varicocele) around the testicle, especially the right testicle, may indicate a large kidney tumor.
- If you’re concerned about the changes you’re experiencing, see a doctor.
Diagnosis Kidney Cancer
Maybe you’ve had symptoms of kidney cancer, such as low back pain, weight loss, or extreme tiredness, or maybe your doctor found a lump on your side during a routine exam or signs of kidney cancer during a check-up for another health problem. Regardless, to confirm a diagnosis of kidney cancer, you will need a thorough physical examination, medical history, and several tests.
The doctor examines the abdomen and sides of the body for lumps and checks for fever and high blood pressure. The doctor will also ask about health habits, medical history, and medications. To make a diagnosis of kidney cancer, the doctor will also perform one or more of the following tests:
- Urine test to check for blood in the urine or other signs of a problem.
- Blood tests to show how well the kidneys are working.
- Intravenous pyelogram (IVP) which involves X-raying the kidneys after the doctor injects a dye that travels down the urinary tract, to highlight any tumors.
- Ultrasound (USG) which uses sound waves to make pictures of the kidneys. This can help tell if the tumor is solid or filled with fluid.
- A CT scan uses X-rays and a computer to make a series of detailed pictures of the kidneys. It may also require dye injections. CT scanning has almost replaced the pyelogram and ultrasound as tools for diagnosing kidney cancer.
- An MRI uses strong magnets and radio waves to make detailed pictures of soft tissues in the body. You may need an injection of a contrast agent to make the picture better.
- Renal arteriogram is used to evaluate the blood supply to the tumor. It’s not done very often, but it can help diagnose small tumors and have other uses.
According to WebMD, unlike many other cancers, doctors may be fairly certain about diagnosing kidney cancer without a biopsy. Sometimes, a biopsy will be taken to confirm the diagnosis. The doctor may use a needle biopsy to take a tissue sample, which is then examined under a microscope for cancer cells. A biopsy can also tell the grade of the cancer, that is, how aggressive the cancer is. Often the surgeon will remove the entire tumor and then examine a tissue sample.
After your doctor has made a diagnosis of kidney cancer, you may need other tests to find out if the cancer has spread within the kidney, to other kidneys, or to other parts of the body (metastasis). You may need a CT scan or MRI. A chest X-ray can show whether the cancer has spread to the lungs. Bone scans can see if the cancer has spread to the bones. These tests will help doctors determine the stage of kidney cancer.
Determining the stage of kidney cancer
Most cancers are grouped by stage, a description of the cancer that helps in planning treatment. The stage of the cancer is based on:
- Location and size of the tumor.
- The extent to which the lymph nodes are affected.
- The extent of spread of the cancer, if any, to other tissues and organs.
- Doctors use information from various tests, including CT, MRI, and biopsies, to determine the stage of the cancer.
- Stage I: The tumor is 7 centimeters (cm) in diameter or smaller and is only in the kidney, has not spread to lymph nodes or other tissues. (Lymph nodes are tiny “filters” that trap germs and cancer cells and store infection-fighting cells.).
- Stage II: The tumor is larger than 7 cm but is still only in the kidney, has not spread to the lymph nodes or other tissues.
- Stage III: The tumor has spread to the major blood vessels—the renal vein and inferior vena cava—or to the tissues around the kidney or to nearby lymph nodes.
- Stage IV: The tumor has spread beyond the kidney to the adrenal glands (small glands on top of the kidneys), or to distant lymph nodes or other organs.
- The tumor is also graded, which is a way of assessing a tumor based on how abnormal the cells are. Tumor assessment can also tell doctors how fast a tumor is likely to grow. Tumors whose cells do not look like normal cells and divide rapidly are called high-grade tumors. High-grade tumors tend to grow and spread more quickly than low-grade tumors.
Treatment For Kidney cancer
The most common treatment for kidney cancer is surgical removal of all or part of the kidney. However, as stated by the National Kidney Foundation, treatment depends on the stage of the disease, general health condition, age, and other factors.
Surgery is the most common treatment for kidney cancer—most people with early-stage cancer (stages 1, 2, and 3) can be cured with surgery.
- Partial nephrectomy: In a partial nephrectomy, the tumor or part of the kidney with the tumor is removed to leave as much of the kidney as possible.
- Radical nephrectomy: In a radical nephrectomy, the entire kidney is removed. If needed, surrounding tissue and lymph nodes may also be removed.
- Surgical approaches that can be performed by surgeons include:Open surgery: Traditional surgery with long incisions.
- Laparoscopy: The surgery is performed with a video camera and thin instruments for smaller incisions.
- Robotics: Laparoscopic surgery is performed with the help of robots.
- Non-surgical treatment optionsThermal ablation: Thermal ablation kills tumors by burning or freezing, and is most often used for small tumors in people who are not good candidates for nephrectomy surgery. Active surveillance: Active surveillance is used if the tumor is smaller than 4 cm.
- Chemotherapy and radiation: Forms of chemotherapy and radiation used for other forms of cancer are usually not effective treatments for most forms of kidney cancer.
Treatment of advanced or recurrent kidney cancer
For people with advanced kidney cancer that has spread to other parts of the body. Drug treatment may be recommended alongside surgery, or instead of surgery. Some of these drugs are given as oral pills, while others are given as injections. Much progress has been made in recent years, and people with advanced kidney cancer are living longer than they were ten years ago.
Medications are often used for advanced kidney cancer. That has spread to other parts of the body or for which surgery is not possible.
- Immunotherapy uses the immune system to stop or slow down the growth of cancer cells.
- Monoclonal antibodies attack specific parts of the cancer cells.
- Checkpoint inhibitors help the immune system recognize and attack cancer cells.
- Vaccines provide an overall boost to the immune system.
Anti-angiogenic therapy reduces the blood supply to tumors to slow or stop their growth.
Targeted therapy directly inhibits cancer growth.
Taking steps to improve your health can help reduce your risk of kidney cancer. Try to:
- Quit smoking: If you smoke, stop. There are many options for quitting, including support programs, medications, and nicotine replacement products. Tell your doctor that you want to stop and discuss the options available.
- Maintain a healthy weight: Work to maintain a healthy weight. If you are overweight or obese, reduce your daily calorie intake and try to be physically active most days of the week. Ask your doctor about other healthy strategies to help you lose weight.
- Controlling high blood pressure: If your blood pressure is high, you and your doctor can discuss options to lower it. Regular exercise, weight loss, and dietary changes can help. Some people may need to take medication to lower their blood pressure.
- Being diagnosed with kidney cancer can be scary, sad, and frustrating.
In addition to treatment from your doctor, joining a local support group or seeking help from a counselor. This can help you maintain a healthy emotional outlook during difficult times.
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