Oncology

Kidney Cancer

A kidney tumor is an abnormal growth within the substance of the kidney. The terms "mass," "lesion" and "tumor" are often used interchangeably. Tumors may be benign (non-cancerous) or malignant (cancerous). The most common kidney lesion is a fluid-filled area called a cyst. Simple cysts are benign and have a typical appearance on imaging studies. They do not progress to cancer, but occasionally require followup and evaluation. Solid kidney tumors are cancerous more than 90 percent of the time. Facts about kidney cancer In the United States, 2 percent of all cancers arise from the kidney. Each year, kidney cancer is diagnosed in approximately 38,000 Americans and is the cause of death in nearly 12,000. Kidney cancer is slightly more common in males and is usually diagnosed between the ages of 50 and 70 years. Solid tumors may be seen on CT scan or the patient may present with painless blood in the urine. The most common kidney cancer is called renal cell carcinoma.

Risk factors for kidney cancer

The following conditions may increase the risk of kidney cancer.

Symptoms for kidney cancer

Many kidney tumors do not produce symptoms and are detected incidentally during the evaluation of an unrelated problem or during routine screening for people who are in high-risk categories (e.g. Von Hippel Lindau disease, tuberous sclerosis). These tumors are usually detected at an early stage. Advanced tumors may cause compression or invasion of structures near the kidney and pain in the flank or back, palpable mass, and blood in the urine. Shortness of breath or coughing up blood may occur when cancer is in the lung. Bone pain or fracture may occur when cancer is in the bone and neurologic symptoms may occur when cancer is in the brain. In some cases, the cancer causes associated clinical or laboratory abnormalities called paraneoplastic syndromes. These syndromes are observed in approximately 20 percent of patients with kidney cancer and can occur in any stage (including cancers confined to the kidney).

Symptoms from paraneoplastic syndromes include weight loss, loss of appetite, fever, sweats and high blood pressure. Laboratory findings include elevated red blood cell sedimentation rate, low blood count, high calcium level in the blood, abnormal liver function tests, elevated alkaline phosphatase in the blood, and high blood count. In many cases, the paraneoplastic syndrome resolves after the cancer is removed. Diagnosis of kidney cancer There are no blood or urine tests that detect the presence of kidney tumors.

When a kidney tumor is suspected, a kidney imaging study is obtained. The imaging study is usually an ultrasound or CT scan. In some cases, a combination of imaging studies may be required to completely evaluate the tumor. If cancer is suspected, the patient should be evaluated to see if the cancer has spread beyond the kidney. An evaluation for metastasis includes an abdominal CT scan or MRI, chest X-ray and blood tests. A bone scan is also recommended if the patient has bone pain, recent bone fractures, or certain abnormalities on their blood tests. Additional tests may be obtained when indicated. Kidney cancer has the tendency to grow into the renal vein, or possibly the vena cava. The portion of the cancer that extends into these large veins is called "tumor thrombus." Imaging studies, particularly MRI, can help determine if tumor thrombus is present.

Stage

The most commonly used staging system for kidney cancer was developed by the American Joint Committee on Cancer (AJCC). The most current version is the 2002 AJCC Staging System. This staging system includes the extent of the primary kidney tumor (T stage), the status of lymph nodes near the kidney (N stage) and the presence or absence of metastases (M stage). In kidney cancer, the lymph nodes near the kidney are referred to as regional lymph nodes. Clinical stage is based on radiographic imaging before surgery, whereas pathologic stage is based on the analysis of surgically removed tissue. Staging the cancer helps predict prognosis and survival. In general, cancers with higher T stage, lymph node metastasis, or distant metastasis have a worse prognosis and shorter survival rates, and these patients need to consider more aggressive treatments.

Grade

Tumor grade is a measure of how aggressive the tumor looks to the pathologist under the microscope; therefore, it is determined from a surgical specimen. Grade cannot be determined from radiographic imaging, blood tests or urine tests. Grade usually ranges from one to three or one to four, with higher numbers indicating a more aggressive tumor. Thus, higher grade implies a worse prognosis.

Should I have a biopsy of the tumor?

For kidney tumors, biopsy is usually not indicated because more than 80 percent of solid kidney tumors are cancers and biopsies have a significant rate of false-negatives. A false-negative means that the biopsy shows no cancer when cancer is actually present. In other words, the biopsy missed the cancer. A false-negative may occur because the tissue obtained was not adequate to determine a diagnosis, the needle missed the lesion (and hit normal surrounding tissue) or the needle hit the lesion but did not hit the cancer. The latter reason can be explained by the fact that some benign tumors can coexist with cancer. For example, oncocytoma (a benign tumor) may coexist with kidney cancer in up to 10 percent of cases. Thus, a biopsy may sample the benign component, but miss the malignant component.

Since a biopsy may miss cancer, the safest approach is to remove the tumor even if the biopsy is negative. In cases where kidney cancer is likely, the current standard of practice is to remove the tumor without performing a biopsy. In very select situations, a biopsy may be recommended when the clinical scenario and radiographic images suggest that the lesion may be from infection, inflammation or cancer from another organ.

Treatment options for localized kidney cancer

When the tumor appears confined to the kidney (a "localized" tumor), there are three main treatment options: tumor removal, tumor ablation and surveillance. Chemotherapy, hormone therapy and radiation therapy are not generally effective treatments for kidney cancer.

Tumor removal

Tumor removal is considered the standard mode of therapy for most patients and is accomplished by performing a surgery called nephrectomy. Radical nephrectomy is surgical removal of everything within Gerota's fascia, including the whole kidney. Partial nephrectomy is surgical removal of part of the kidney (in this case, the part that contains the tumor). The goal of partial nephrectomy is to remove the entire tumor while preserving as much normal kidney tissue as possible. The kidney tissue that is conserved may prevent the need for dialysis if subsequent kidney damage occurs.

Partial or total nephrectomy can be performed through a traditional incision (open surgery) or through several small incisions (laparoscopic surgery). Open nephrectomy Traditional open nephrectomy (partial or radical) is performed through a flank or abdominal incision. This incision is typically 10 to 20 inches in length and may include removal of a rib. In the past, open radical nephrectomy was considered the treatment of choice for tumors that appeared to be confined to the kidney.

Some tumors are single, small and located in an area of the kidney in which a partial nephrectomy can be performed. Not all tumors are treatable with partial nephrectomy. Partial nephrectomy is usually not recommended in patients with tumors that have any of the following characteristics: extension into the renal vein, close proximity to the main kidney vessels or factors that would make complete tumor resection unlikely.

When the tumor cannot be safely removed by partial nephrectomy, radical nephrectomy is performed. If the patient elects to undergo a partial nephrectomy, there is always a risk that the entire kidney may need to be removed. Partial and radical nephrectomies are now considered standard treatments. As stated before, partial nephrectomy is performed to preserve as much normal kidney tissue as possible; however, its complication rate may be slightly higher than radical nephrectomy.

Open partial nephrectomy should be considered in any patient with a small (ideally less than four centimeters) localized kidney tumor and a normal kidney on the opposite side. Open partial nephrectomy is usually the treatment of choice when radical nephrectomy results in either immediate dialysis or a high risk for subsequent dialysis, such as when the patient has a single functioning kidney, poor overall kidney function, medical or genetic diseases that threaten kidney function or bilateral kidney tumors.

Laparoscopic radical nephrectomy Laparoscopy is performed using telescopes that are inserted into the abdominal cavity through small "key hole" incisions; however, a somewhat larger incision is often made to permit removal of an intact kidney. Current data indicate that open and laparoscopic radical nephrectomies have similar complication rates and provide equally effective cancer treatment for patients with tumors that appear confined to the kidney. Compared to open radical nephrectomy, laparoscopic radical nephrectomy has less postoperative pain, shorter hospital stay and shorter recovery time. If you elect to undergo a laparoscopic radical nephrectomy, there is a low risk (usually less than five percent) that the surgeon will need to convert to an open nephrectomy (i.e., convert the "key hole" incisions to a larger incision). Not all patients are candidates for laparoscopic nephrectomy. Laparoscopic radical nephrectomy is best suited for small, localized tumors that have not invaded the lymph nodes. Open nephrectomy is preferred in patients with severe scarring around the kidney or a history of extensive abdominal surgery.

Tumor ablation

Tumor ablation destroys the tumor without surgically removing it. Examples of ablative technologies include cryotherapy, interstitial radiofrequency ablation, high- intensity focused ultrasound, and laser coagulation. Ablation can be accomplished during open surgery, laparoscopy or percutaneously (through the skin). Since renal tumor ablation is a relatively new procedure, long-term results are unknown. However, ablation may be less invasive than nephrectomy and may be useful in patients who cannot tolerate a more extensive surgery. Tumor ablation may also permit a better chance of preserving kidney function in situations when multiple tumors are present. In general, tumor ablation is best reserved for older or somewhat frail patients. The risk to tumor recurrence with these approaches is somewhat higher than with surgical excision.

Embolization

This is not a standard treatment option, but may be considered in patients who cannot tolerate tumor removal or ablation. It may also be considered as an adjunct to standard forms of treatment, especially when the tumor is actively bleeding. Embolization can stop the bleeding and permits physicians to stabilize the patient before surgery. A small catheter is advanced from the groin to the renal artery and is used to deposit small particles in the vessels of the kidney. These particles block the flow of blood to the tumor and, therefore, stop active bleeding. Furthermore, without a blood supply, the tumor shrinks. Since it is unclear whether or not embolization completely eliminates the tumor, it is not considered a primary form of therapy for kidney cancer.

Treatment options for tumors that have spread

When the tumor has spread to other organs, there have traditionally been four primary treatment options: nephrectomy followed by immunotherapy, initial treatment with immunotherapy, clinical research trials and surveillance. More recently, a new category of treatment has been added, namely treatment with drugs that block the blood flow into the cancer (anti-angiogenic agents). Initial treatment with immunotherapy: In some patients, surgery may be too risky. These patients may be treated initially with immunotherapy. If they respond adequately and if their medical condition improves, they may undergo surgical removal of the remaining tumor.

Clinical research trials

Research protocols are not available to all patients. If you are interested in finding out more about these protocols, please ask us at UAA. There are many non-standard therapies that are being studied in research trials. Some of these therapies include cellular immunotherapy, tumor vaccines, gene therapy, stem cell transplants, anti-angiogenesis therapy, inhibitors of growth factors, etc. Although these therapies appear promising, they are still experimental and it is unclear whether or not they are effective treatments for kidney cancer. Radiation: Radiation therapy is not used to cure kidney cancer, but rather for alleviation of symptomatic metastasis. For example, the pain from bone metastases can be relieved by radiation to bone lesions. It may be used alone or in combination with other therapies.

Surveillance:

May be appropriate when any of the following are present: the kidney tumor has a low probability of being cancer; the patient cannot tolerate treatment; the patient has a short life expectancy (i.e., they are likely to pass away from other causes); or the patient does not want treatment. With lesions that have a low probability of being cancer, regular follow up with a physician is mandatory. Angiomyolipoma is a benign kidney tumor that can be diagnosed by CT scan. Patients with angiomyolipoma may undergo surveillance with periodic imaging studies. However, embolization or surgical removal (preferably by partial nephrectomy) may be necessary if the angiomyolipoma becomes symptomatic, bleeds or grows to greater than four centimeters in size.

Kidney function

When kidney tissue is removed or destroyed, the remaining functional kidney tissue usually works sufficiently to avoid problems. Kidney function should be assessed periodically. In a patient who undergoes a radical or partial nephrectomy on one side and has a normal kidney on the other side, the need for dialysis is extremely rare. In fact, people can live a normal life with only one functioning kidney.

When a patient has only one kidney (a "solitary" kidney) and part of that kidney needs to be removed, the risk of permanent dialysis is real. In most cases, kidney dysfunction is temporary and improves without treatment. When the remaining functional renal tissue is less then an entire kidney, there is a risk that the function of that tissue will deteriorate over time. This deterioration is called "hyperfiltration renal injury" and may occur up to 10 years after surgery. In some cases, the chance of hyperfiltration renal injury can be reduced through careful monitoring. Therefore, in patients with less than one whole kidney remaining, close surveillance of kidney function is particularly important and should include blood pressure measurement and 24-hour urine collection to carefully assess remaining kidney function.

Prognosis

There are many factors that affect outcome after treatment for kidney cancer. However, the two most important prognostic factors are tumor stage and grade. The basic concept is that the more extensive the tumor (and thus the higher the stage), the less likely that treatment will achieve cure. Higher grade also implies a lower chance of cure. The chance of cure with long-term followup is well defined for partial and radical open nephrectomy. In addition, long-term follow up for laparoscopic radical nephrectomy has been accumulating and appears to be similar to open radical nephrectomy, assuming careful patient selection (some patients are not good candidates for laparoscopic surgery and should have conventional surgery).

Additional treatment

When the tumor is benign, no further therapy is needed. When the tumor is malignant and completely removed, patients can be adequately treated with surgery alone. Additional treatment may be considered when there is advanced local cancer stage, spread to the lymph nodes or metastasis to distant organs. Life expectancy and surveillance Most patients can live a normal life with a single, adequately functioning kidney. Even in cases when the remaining kidney is functioning sub-optimally, the patient may still be able to live a normal life. Dialysis is rarely necessary. After treatment for kidney cancer, routine life-long surveillance is necessary. At UAA, surveillance typically consists of periodic assessment by your urologist, blood tests and X-rays. There is no standard surveillance protocol; therefore, your urologist will determine the necessary tests and their timing based on your unique situation. In general, tumors of advanced stage are higher risk and require more intensive surveillance.

Protection of the remaining kidney

In patients with only one kidney, it may be prudent to avoid collision/contact sports (football, hockey, boxing, soccer, basketball, etc.) and limited contact sports (baseball, gymnastics, skiing bicycling, etc.) to prevent traumatic injury to the remaining kidney. It may also be prudent to avoid routine use of medicines that can cause kidney damage. Medicines such as non-steroidal anti-inflammatory drugs (ibuprofen, aspirin, etc.) and intravenous iodine contrast (primarily used for certain X-rays) can cause kidney damage in rare situations. Thus, it is best to use these substances only when necessary.

Some medical conditions, such as hypertensio, diabetes, high cholesterol and obesity, have the potential to cause deterioration of kidney function. Treatment of these conditions may prevent kidney damage. Therefore, it is important that you comply with physician-supervised treatment of these conditions. Routine follow up of kidney function is recommended. If your physician detects evidence of hyperfiltration renal injury, additional preventative therapy may be instituted. What can I do to prevent the recurrence of kidney cancer? There are no proven ways to prevent recurrence of kidney cancer; however, it may be prudent to stop smoking. It is extremely important to follow up with your urologist on a regular basis.