Kidney Cancer: Signs, Symptoms, and Treatment Options

Like any of the body's organs, the kidney can develop cancer. Approximately 32,000 cases of kidney cancer are diagnosed in the United States alone each year, and approximately 11,000 people a year die of kidney cancer in the United States. The disease is more common in men and is most common in the sixth and seventh decades of life.

"Kidney cancer" is not a disease per se, but rather is a group of cancers that arise form different parts of the kidney tubules. Kidney cancers were divided into the following subtypes: Common or conventional renal cell carcinoma, papillary renal cell carcinoma, chromophobe renal cell carcinoma, collecting duct carcinoma (including medullary carcinoma), and renal cell carcinoma, which cannot be classified. An expert panel also classified benign kidney growths such as metanephric adenoma, metanephric adenofibroma, and renal oncocytoma.

Another system used to quantify the aggressiveness of kidney cancer is grading. By looking at the cells that make up a cancer, the cells are divided into low grade tumors which are less aggressive and higher grade tumors which are more aggressive. The Fuhrman classification was originally designed for conventional kidney cancers but is often used to grade all different kidney cancer varieties. Tumors are graded from I to IV with the lower grade tumors being less aggressive. Just as with the different subtypes, different grades have different outcomes.

Kidney cancer can present with a variety of different signs and symptoms, which are listed below. None of these signs or symptoms are specific to kidney cancer itself. Indeed, kidney cancer is not the most common disease associated with the majority of these symptoms. Today, the majority of kidney cancers are discovered while very small in size and typically will have no associated symptoms.

Signs and Symptoms Associated with Kidney Cancer:

• Blood in urine ("hematuria")
• Pain in the back just below the ribs
• A mass that can be felt
• Unexplained weight loss which can sometimes be rapid
• Intermittent fevers or night sweats
• Fatigue and lethargy
• Fever that is not associated with a cold or the flu
• Pain in other parts of the body if the cancer has spread

It has long been known that for each different type of cancer there are distinct risk factors. These factors do not assure that an individual will have cancer, but increase the chances of developing the cancer. The mechanism by which the majority of these risk factors result in cancer is not always known, but epidemiological studies do allow physicians to identify factors which are associated with each different type of cancer.

In the past, the majority of kidney cancers were identified due to symptoms. These characteristic symptoms are still seen in a minority of people who present with larger kidney cancers.

However, today, the majority of kidney cancers are "incidental findings." The term incidental finding simply means that the kidney tumor, which is usually small in diameter, was found during the evaluation of a separate process. Often, a sonogram will be ordered for a non-specific complaint and a kidney mass will be identified.

Today, the reason that the majority of kidney tumors are discovered while still very small in size is the increased use of radiologic tests. These tests have become important in identifying kidney masses as well as in determining if the mass is suspicious for kidney cancer. Unfortunately, with contemporary radiographic technology, it remains impossible to determine if the mass is truly a kidney cancer as opposed to some other non-cancerous growth in the kidney.

Depending on the size of the mass, the probability of kidney cancer can be estimated. Smaller kidney masses can be benign growths 30-40% of the time. In contrast, larger kidney growths are more commonly kidney cancer (over 90%). Naturally, it would seem that a small procedure like a biopsy to take a small sample of the kidney mass tissue would be prudent. However, biopsy is not usually indicated for several reasons.