Renal cell carcinoma is a type of cancer that starts in the lining of the tubules, or the small tubes found inside the kidney.
It is the most common type of kidney cancer, accounting for over 90% of kidney cancers in adults. According to the American Cancer Society, it affects around 51,000 Americans every year and is fatal in 30% of cases.
Like many cancers, renal cell carcinoma doesn’t have any known causes. However, doctors have identified several risk factors, the most common of which are as follows:
- Age: Renal cell carcinoma is most common in people aged over 60.
- Smoking: Smokers are about three times as likely to develop RCC as non-smokers.
- Obesity: People who are more than 30 pounds overweight have a higher risk of developing the cancer.
- Exposure to chemicals: Kidney cancer occurs more often in workplaces exposed to cadmium, asbestos, and trichloroethylene (a common industrial solvent).
- Previous kidney problems: People who have had previous kidney failures, are undergoing dialysis, or are taking immunosuppressant drugs are more at risk.
Signs and Symptoms
Early-stage renal cell carcinoma rarely produces any symptoms. Most of the signs appear when the cancer has reached later stages. These include:
- Blood in the urine (urine may appear pink, red, or brown)
- Lower back pain
- Unexplained weight loss
- Frequent fatigue
- Irregular fevers
Diagnosis and Staging
Blood and urine tests are usually the initial steps for diagnosing kidney cancer. If the patient has one or more risk factors, or if the tests indicate a kidney problem, the doctor may spot tumors using X-rays, ultrasounds, and CT and MRI scans. The cancer is usually confirmed with a biopsy of the kidney tissue.
Once the cancer is diagnosed, the doctor will perform additional tests to see how far it has progressed. Staging tests vary from case to case, depending on where the cancer is likely to have spread. Common procedures include additional scans, chest x-rays, and fluoroscopy.
Renal cell carcinoma occurs in four stages:
Stage I: The tumor is relatively small and localized in the kidney.
Stage II: The tumor is still confined to the kidney, but has grown noticeably larger.
Stage III: The tumor has spread outside the kidney, most commonly to the adrenal glands and nearby lymph nodes.
Stage IV: The cancer has affected other parts of the body, including vital organs such as the lungs and liver.
The prognosis for renal cell carcinoma depends on the stage and the general health of the patient. For cancers that haven’t metastasized, the overall survival rate is 60 to 80%. Cases that are found and treated early have a much higher survival rate.
Renal cell carcinoma is resistant to conventional treatments like radiotherapy and Majority of renal cell carcinomas are treated with nephrectomy, or removal of all or part of the affected kidney. Early-stage tumors may be removed by themselves, so that the patient doesn’t lose kidney function. For Stage II and Stage III cancers, the surrounding organs may also be removed to avoid further spread. This procedure is called radical nephrectomy.
If surgery isn’t an option, other treatments may be used, although some have a lower survival rate. These include:
- Embolization: This involves blocking blood flow to the tumor, keeping it from spreading outside the kidney.
- Cryoablation: In this treatment, tumors are destroyed by repeatedly freezing and thawing the cancer cells. This is one of the most effective alternatives to surgery, with a survival rate of 90% to 95% for tumors less than 4cm in size.
- Immunotherapy: Also called biological therapy, this method makes use of drugs that direct the body’s immune system to destroy the cancer cells. The drugs are usually a combination of interleukin-2 and interferon, which are both synthetic versions of naturally occurring proteins.
Since there is no specific cause, the best way to prevent kidney cancer is to avoid the known risk factors. This includes maintaining a healthy weight, avoiding processed foods, and quitting unhealthy habits such as smoking and drinking. People with one or more risk factors should be screened at least once a year, so that cancer can be detected and treated early.