Kidney Cancer

The kidneys are two bean shaped organs located on either side of the spine fixed to the upper back wall of the abdominal cavity and protected by the lower rib cage. They are each approximately the size of a fist and weigh 4 to 5 ounces. Their primary function is to filter the blood and rid the body of excess fluid, salt and waste products in the form of urine which flows through tubes (ureters) to the bladder.

Although there are several types of cancer that can develop in the kidney, the most common type is renal cell carcinoma (adenocarcinoma) which accounts for 85% of all kidney cancer. Renal cell carcinoma begins in the cells which line the tubules within the kidneys. Transitional cell carcinoma is a less common type of kidney tumor (5-10%), which begins in the inner lining of the kidney where urine collects before flowing to the bladder. Since the inner layer of cells in the collecting system, the ureter, and the bladder are the same type, transitional cell cancer can occur in any of these locations.

Kidney cancer is one of the 10 most common cancers, and with a higher incidence in males than females. The American Cancer Society estimates that there will be 54,390 new cases of kidney cancer (33,130 in men and 21,260 in women) in the United States in 2008, and about 13,010 people (8,100 men and 4,910 women) will die from this disease.

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Evaluation

Causes and risk factors

There are several factors known to increase the risk of developing renal cancer. Some of these are:

Smoking: Smoking has been shown to increase the risk of developing renal cancer. The risk decreases if you stop smoking, but it takes many years to approach the level of someone who never smoked.

Obesity: Some studies have shown a higher risk of developing renal cell cancer in people who are overweight.

Environmental Exposure: Studies have suggested that exposure to certain substances increases the risk for renal cell cancer, some of which are asbestos, cadmium (a type of metal), some herbicides, benzene, organic solvents (trichloroethylene) and chemicals associated with products such as batteries, paints or welding materials

Genetic cause: Certain genetic factors and hereditary medical conditions such as Von Hippel Lindau disease may increase the risk of developing kidney cancer. Patients with a strong family history also have a higher risk of this disease.

Gender and race: Men are twice as likely as women to develop renal cancer. Blacks have a slightly higher risk than whites.

Early detection, diagnosis and staging

Kidney cancers are often detected when they are small and localized to the kidney. Today, 50% of kidney cancers are diagnosed during imaging studies (most commonly CT scan) done for symptoms unrelated to kidney disease. For that reason, kidney cancer is diagnosed earlier than in the past when signs and symptoms prompting investigation did not occur until the cancer had grown large or spread to other organs. Kidney cancer in its earliest stage does not cause abnormal symptoms.

Some of the presenting symptoms and signs of renal cancer include: blood in the urine (hematuria), low flank or back pain, abdominal mass, fatigue (unexplained or due to anemia), loss of appetite, unexplained weight loss, unexplained persistent fever, swelling of ankles and legs (edema). These symptoms are not specific to kidney cancer and require evaluation by a physician.

Diagnosis

Imaging studies: Renal imaging studies are the mainstay of diagnosis of renal tumors.

CT scan: Computerized Tomography (CT) is a technique of acquiring cross sectional images of the body. These images can be further reconstructed to provide detailed information regarding the presence of kidney tumors as well as the extent and spread of the cancer to other surrounding organs. This is an extremely useful test for the diagnosis of renal cancer and also provides important information to the surgeon for planning the appropriate treatment.

MRI: Magnetic Resonance Imaging (MRI) uses magnetic waves to produce images of the kidneys and other abdominal organs. It is particularly useful in detecting the presence of tumor within the blood vessels of the kidney (MR Angiography).

Ultrasonography: Renal ultrasound utilizes sound waves to detect kidney masses. This is often useful in differentiating the solid versus fluid (cyst) content of the renal mass. This can also be used to evaluate the blood vessels of the kidney for presence of tumor involvement. This test avoids the use of any radiation to the patient.

Angiography: This is an X-ray study of the blood vessels of the body in which images are obtained following the injection of contrast material (dye). This can be used to view the blood supply of the kidney and the tumor which can further provide a map if surgery is indicated. The information about the tumor’s blood supply can also be used to block the blood flowing into large tumors (embolization) just prior to surgery, decreasing blood loss during operation.

Renal scan: Combined with a simple blood test, this nuclear scan provides information regarding total kidney function and each kidney’s relative contribution to total function (right v left). A small amount of radioactive material is injected into the blood. The radioactive material accumulates in the kidneys and is then excreted into the bladder. The rate of excretion of the radioactive material is used to assess the kidney’s function.

Bone scan: This test is used to determine whether the kidney cancer has spread to bone. It is performed by injecting a radioactive material and acquiring images of the bones using special scanning equipment.

Chest X-ray or CT scan: Imaging study of the chest is performed to determine if kidney cancer has spread to the lungs.

Urinalysis: The urine is examined microscopically for the presence of blood (hematuria) or abnormal cells suspicious for cancer (cytology).

Ureteroscopy: This is a surgical procedure that involves the insertion of a flexible tube (endoscope) through the urethra into the bladder and through the ureter into the kidney. This is done under general anesthesia and is useful to inspect the inner lining of the kidneys and ureters for presence of tumors. If indicated, the tumors can be biopsied during the procedure.

Biopsy (Ultrasound or CT guided): In general, we do not recommend kidney biopsy for solid tumors because of the frequent false negative results (tumor is present but the biopsy needle did not retrieve the cancer tissue) and because of the potential risk of spreading tumor in the biopsy needle tract. In patients with a known malignancy or in patients with suspected lymphoma, biopsy is reasonable because in those situations, if the tumor is not of renal origin, the kidney may remain while chemotherapy is administered.

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Treatment

There are various treatment options available to treat kidney cancer including surgery, chemotherapy, immunotherapy or a combination of these treatments. Radiation therapy has not been helpful in treating kidney cancer. In choosing a treatment plan, one of the most important factors is the stage of the cancer. Other factors to consider are the patient’s overall health, the likely side effects of the treatment, and the probability of curing the disease, extending life, or relieving the symptoms.

Surgery is generally considered to be the primary treatment for kidney cancer. Even when metastatic spread is demonstrated outside the kidney, operative removal of the primary tumor provides tissue pathologic diagnosis that helps guide choice of treatment. Removal of the primary tumor site reduces complications associated with kidney cancer including bleeding and tumor necrosis.

Operative treatment for kidney cancer can be categorized based upon what is done to the kidney or based upon what technique is used to accomplish the goal.

Categories of Renal Surgery

Extent of resection:

1. Radical nephrectomy: removal of the kidney, the adjacent adrenal gland, and a segment of the ureter with adjacent lymph nodes. This surgery is indicated when the renal mass is situated in a part of the kidney that prevents removal of the tumor without damaging the kidney beyond salvage. Examples include tumors that invade major blood vessels leading into or out of the kidney, or tumors that invade into the collecting system that might make reconstruction of the kidney impossible after the cancer is removed.
2. Radical nephrectomy with removal of inferior vena cava (IVC) tumor thrombus: removal of the kidney, adrenal, lymph nodes, and tumor which has grown into the renal vein and extended into the inferior vena cava- the major vein that takes blood back to the heart from the lower torso and legs. Kidney cancers can invade the renal vein that takes blood from the kidney into the vena cava and up to the heart. If the IVC tumor can be removed with any IVC wall that is attached, prognosis is good. However, these operations become more complicated if the tumor thrombus extends through the IVC up to the heart which requires a combined team surgery with urology and cardiothoracic surgery.
3. Partial nephrectomy: removal of the kidney tumor with a margin of surrounding normal kidney. When the tumor is on the surface of the kidney, is smaller than 4 cm, and does not invade the arterial or venous blood supply, then removal of the tumor and surrounding normal tissue is a reasonable alternative to removal of the entire kidney. Of course, frozen section pathology to examine the edges of the removed kidney is mandatory; if any margin is positive indicating cancer left behind, then either more tissue is removed or the entire kidney is removed. Partial nephrectomies are clearly indicated in patients with only one functioning kidney, or in patients who are at risk for kidney failure (especially patients with hypertension or diabetes).
4. Nephroureterectomy: removal of the kidney and the entire ureter including a cuff or collar of bladder at the point where the ureter enters the bladder. This surgery is indicated in patients whose cancer is the transitional cell type- the cells that line the collecting system or the ureter. Occasionally, in patients with a solitary kidney, small transitional cell cancers can be managed with resection using telescope instruments, similar to management of small bladder cancers. However, with invasive disease, the kidney and ureter must be removed together.

Surgical approach

1. Open surgery: The traditional surgical technique for the treatment of renal cancer has been open surgery. Open nephrectomy can be done through a variety of incisions depending upon surgeon’s preference and the size and location of the tumor. These approaches include an incision below the rib cage in front (anterior subcostal), incision below the rib cage in the flank (infracostal flank incision), incision over either the 11th or 12th rib with removal of the rib (flank incision), or incision above the 10th rib with entry into the thoracic cavity, and incision of the diaphragm (thoracoabdominal incision) which is used in cases of very large and superior tumors.
2. Laparoscopic surgery: Laparoscopic nephrectomy has been performed since 1994 and extended follow-up has demonstrated that the results in terms of cancer treatment are equal to results obtained using open surgical techniques. Laparoscopy has the advantage of decreased hospital stay and shorter time to recovery with return to preoperative activity. Laparoscopy can be used for all types of renal surgery (radical, partial, or nephroureterectomy). Removal of the tumor intact (without crushing or dividing into smaller fragments) enables the pathologist to identify any areas suspicious for cancer at the cut edge - information which may influence the surgery or subsequent chemotherapy. Therefore, laparoscopy is used in cases of partial nephrectomy with the section of the kidney placed in a bag and a small incision made to permit removal of the tissue specimen intact.
3. Robot-assisted laparoscopic surgery: Same indications as laparoscopic surgery but using the daVinci robot to assist in performing the operative excision and especially useful in partial nephrectomy which requires reconstruction of the kidney using laparoscopic suture techniques.
4. Hand-assisted laparoscopic surgery: When removal of the entire kidney is necessary, the surgeon will insert a hand into the abdomen to facilitate dissection and removal of the kidney (and in some cases, removal of the entire ureter). The incision providing access for insertion of the hand is then enlarged just enough to allow kidney extraction.
5. Cryosurgery or Radio Frequency Ablation (RFA): In the recent past, use of radiofrequency probes (heating the tissues) and cyrotherapy probes (freezing the tissues) has gained some favor in kidney, liver, and lung tumors when clinical circumstances make the risk of surgical removal by partial or radical nephrectomy prohibitive. RFA can be performed either under laparoscopic exposure with general anesthesia or, for posterior tumors, percutaneous CT or ultrasound guided probe insertion. In either case, once the probe is securely engaged in the kidney mass, the tumor is heated and cooled 3 times followed by probe removal. A similar technique can be used with the cryotherapy probes except that all exposures are performed using laparoscopy. In either case, follow-up must be diligent with CT scans at 1, 3, and 6 month intervals to assure that the tumor ablation is successful. This approach is not considered standard of care at this time. Limitations include size (not greater than 4 cm) and location (not adjacent to major blood vessels or the collecting system which dampen temperature probe affect and not adjacent to neighboring hollow organs which might be injured by heat extremes).

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The University of Cincinnati Urology Division is one of the leading urology programs, not just in Cincinnati, but in the U.S. UC Urology provides quality health care using the most advanced technology and state-of-the-art diagnostic treatments. Many of our urologists are recognized in multiple national and local "Best Doctors" and "Top Doctors" listings. We provide minimally invasive surgical treatments which include laparoscopic, robot-assisted laparoscopic and endourologic procedures as well as comprehensive care for all urologic conditions.