Kidney Cancer: Renal Mass

How common is kidney cancer?

It is estimated that there are approximately 55,000 cases of kidney cancer that are diagnosed in the United States each year and 13,000 deaths due to this disease. Average age at diagnosis for renal cell carcinoma is in the early 60s.

Renal Cell Carcinoma (RCC), which represents 2% of all adult cancers, is the most lethal of common urologic cancers, with approximately 35% of patients dying from the disease at the five-year mark. Renal cell carcinoma incidence rates have risen steadily each year during the last three decades in most of the world, with an average increase of 2% to 3% per year.

What are the types of kidney cancer?

The kidney is composed of two parts, the main substance of the kidney (called the parenchyma) and the drainage system. Renal Cell Carcinoma (RCC) is cancer of the kidney parenchyma and accounts for approximately 85% of kidney cancers diagnosed in the United States. Transitional cell carcinoma (also called urothelial cancer) develops in the drainage system of the kidney and accounts for most of the other cases of kidney cancer.

What are risk factors for renal cell carcinoma (RCC)?

Tobacco use and obesity are the main risk factors for RCC, accounting for about 20% and 30% of cases, respectively. High blood pressure has also been demonstrated to increase the risk of RCC development. Family history is associated with increased risk for kidney cancer development, with inherited forms accounting for approximately two to four percent of cases.

What are the symptoms of RCC?

More than half of kidney cancers are found incidentally, during imaging studies (for example, at CT scan or an ultrasound) carried out for an unrelated issue. This is particularly true for small renal masses, under 7 centimeters (2.8 inches)

How is RCC diagnosed?

A renal mass may be discovered on imaging done for other reasons. If a renal mass is first discovered on ultrasound, further investigation may include a computed tomography (CT) scan, before and after administration of contrast (dye) in the vein. Magnetic resonance imaging (MRI) before and after administration of contrast (dye) in the vein may be used as well.

Other studies may be done to evaluate for spread of cancer, including blood work, chest x-ray and sometimes bone scan. Biopsy of the mass may be done in select circumstances, for example, in patients who have a history of other types of cancer, or in those considering thermal therapy or kidney removal.

About 20% of small renal masses thought to be RCC, may be a benign (noncancerous) growth such as an oncomyocytoma or an angiomyolipoma (a collection of vessels, muscle and fat).

How is RCC treated?

Renal cell carcinomas can have a wide range of clinical behaviors. Some tumors grow slowly and remain in the kidney, while others may grow rapidly and spread throughout the body. Management options range from observation to surgical removal of the kidney. The treatment strategy is based on the size and characteristics of the tumor on CT scan as well as the patient’s health and treatment goals.

Surveillance

Patients diagnosed with a small renal mass may be candidates for surveillance of the tumor with periodic imaging studies (such as CT, MRI or ultrasound). Indications for surveillance include elderly patients or patients with multiple health problems, who are not healthy enough for surgical intervention. Observation, with plans to treat if the mass grows, may be another treatment strategy.

Radical nephrectomy

Large renal cancers or cancers in the middle of the kidney are best treated with removal of the entire kidney, including the fat around the kidney and sometimes the adrenal gland above the kidney. This surgery is called a radical nephrectomy and can be performed with different techniques, either through open surgery (through an incision) or a laparoscopic approach, at times with the use of the laparoscopic robot.

Hazards of nephrectomy may include damage to surrounding organs such as bowel or blood vessels, bleeding, infection and anesthetic complications. After surgery, ongoing follow-up is indicated, which may include a medical history, physical exam, blood work, chest x-ray, ultrasound or CT scan.

Partial nephrectomy

Cancers that occupy only a portion of the kidney can be surgically removed by excising the cancer and a rim of normal tissue using a technique called a partial nephrectomy. This can be done using open (incision), laparoscopic (keyhole) or robotic surgery. The benefit of a partial nephrectomy is that it allows preservation of healthy kidney tissue. This maximizes overall kidney function and decreases the risk of cardiovascular disease. This is especially important for people with risk factors for impaired kidney function, such as high blood pressure, high cholesterol, diabetes and smoking.

Hazards of partial nephrectomy include bleeding, transfusion, urine leak, infection, damage to surrounding organs (such as bowel or blood vessels), the need for conversion to a radical nephrectomy and anesthetic complications. As with radical nephrectomy, ongoing follow-up to monitor for potential recurrent disease is indicated, which may include a medical history, physical exam, blood work, chest x-ray, and ultrasound or CT scan.

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Ablative therapy

Recently, ablative therapy has been introduced as a minimally-invasive method to treat the kidney cancer while leaving healthy kidney tissue behind. Ablative therapy is delivered to the cancer with small needles or probes under imaging guidance (such as CT scan) or during surgery. Biopsy of the tumor is often done prior to the ablative therapy.

Currently there are two methods of ablating RCC, cryotherapy and radiofrequency ablation. Cryotherapy freezes the kidney cancer while radiofrequency ablation uses heat to destroy the kidney cancer. The advantage of ablative therapy is that it can be administered in a minimally-invasive fashion, which allows preservation of a large amount of healthy kidney tissue. The disadvantage of this type of therapy is that the long-term outcomes are still being studied. Monitoring of the kidneys, often with CT scan, is necessary and retreatment or surgery may be needed if the cancer recurs.

How can I decrease my risk of RCC?

Moderation of alcohol exposure, and increased fruit, vegetable, and fatty fish consumption have been reported to reduce the risk of RCC. Nonsteroidal anti-inflammatory agents (for example, ibuprofen or Advil) have not been found to play a role in the development of kidney cancer.

If you have a personal or family history of kidney cancer, be sure to discuss this with your doctor or urologist to be sure your kidneys are being monitored appropriately.