Kidney Cancer

written by Dr George Lee Eng Geap on 15 July 2011

Kidney Cancer

What is kidney cancer?
 
Most people have two functional kidneys. The kidneys produce urine that drains through narrow tubes (called ureters) into the bladder. 
 
The kidney have many functions, such as controlling fluid balance, regulating salt composites, preventing acid buildup, eliminating waste products, producing urine, and regulating blood pressure. 
 
The kidney also manufactures a hormone that stimulates the production of red blood cells. Most people can function with only one kidney. If kidney function is severely impaired in conditions such as chronic diabetes, dialysis may be required.
 
A kidney tumor is an abnormal growth within the kidney. 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 and usually require no follow up or treatment. Solid kidney tumors can be benign, but are cancerous more than 90 percent of the time. 
 
Kidney cancer is slightly more common in males and is usually diagnosed between the ages of 50 and 70 years. The most common kidney cancer is called renal cell carcinoma.
 
What risk factors are associated with kidney cancer?
 
The following associations may increase the risk of developing kidney cancer.
 
Smoking 
Family history of kidney cancer
Polycystic kidney disease
Chronic kidney failure and/or dialysis
Diet with high caloric intake or fried/sautéed meat
von Hippel Lindau disease
 
What are the symptoms for kidney cancer?
 
Many kidney tumors do not produce symptoms, but may be detected incidentally during the evaluation of an unrelated problem. However, some people may have flank pain or discomfort, palpable mass, and blood in the urine (microscopic or grossly visible). 
 
If cancer spreads beyond the kidney, symptoms depend upon the involved organ. 
 
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. Some patients may have symptoms which include weight loss, loss of appetite, fever, sweats and high blood pressure.
 
How is kidney cancer diagnosed?
 
When a kidney tumor is suspected, a kidney imaging study is obtained. The initial 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. A bone scan is also recommended if the patient has bone pain, recent bone fractures, or certain abnormalities on their blood tests.
 
What are the different stages of kidney cancer?
 
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.
 
What are different grades of kidney cancers?
 
Tumor grade is a subjective measure of how aggressive the tumor looks under the microscope; therefore, it is determined from a surgical specimen. 
 
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.
 
 
What are the treatment options for tumors that appear confined to the kidney?
 
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 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 the surrounding fat of the 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. 
 
Nephrectomy can be performed through a traditional incision (open surgery) or through laparoscopic surgery.
 
Open nephrectomy (radical and partial): Traditional open nephrectomy 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. 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. 
 
If you elect to undergo a partial nephrectomy, there is always a risk that the entire kidney may need to be removed.
 
Laparoscopic radical nephrectomy: Laparoscopic nephrectomy is performed using scopes 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. 
 
A nephrectomy performed by inserting the scopes into the cavity that surrounds the kidney (rather than into the abdominal cavity) is called retroperitoneoscopic nephrectomy. Laparoscopic radical nephrectomy has less postoperative pain, shorter hospital stay and shorter recovery time. Laparoscopic radical nephrectomy is best suited for small, localized tumours.
 
Tumor ablation: Tumor ablation destroys the tumor without surgically removing it. Examples of ablative technologies include cryotherapy, interstitial radiofrequency ablation, high- intensity focused ultrasound, microwave thermotherapy and laser coagulation. 
 
Ablation may be less invasive than nephrectomy and may be useful in patients who cannot tolerate a more extensive surgery. The risk of tumor recurrence with these approaches is somewhat higher than with surgical excision.
 
 
What are the treatment options for tumors that invade the renal vein or vena cava?
 
When tumor invades into the renal vein or vena cava, open surgery is recommended to remove the affected kidney and to extract the tumor from the veins. It is important that you seek a urologist who has experience with this type of surgery. This is a major operation that requires isolation and clamping of the inferior vena cava, the largest vein in the body. 
 
After the blood flow is blocked the vein is opened and the tumor thrombus is extracted. The vein is then sutured closed.
 
What are the treatment options for tumors that have spread to other organs?
 
When the tumor has spread to other organs, there have traditionally been four primary treatment options: 
 
1. Nephrectomy followed by immunotherapy,
2. Initial treatment with immunotherapy, 
3. Treatments that are at the clinical research trials stage and,
4. 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, see below).
 
Immunotherapy: Immunotherapy stimulates your immune system to attack cancer. Hopefully, the immune system will eliminate cancer in much the same way it eliminates the flu. The most commonly used immunotherapy agents are interleukin-2 (IL-2) and interferon. 
 
Approximately 5-7 percent of patients have complete cancer regression—most of those patients have been treated with the high dose IL-2 protocol. 
 
The most common side effects of immunotherapy are similar to flu symptoms and
include fever, chills, nausea, vomiting, diarrhea and fatigue. Other side effects include low blood pressure, fluid accumulation in the lungs (pulmonary edema), impaired liver function, impaired kidney function, mental status changes (such as confusion, agitation, disrupted sleep pattern), rapid heartbeat and irregular heartbeat.
 
Anti-angiogenic therapies: Tumors must stimulate the in growth of blood vessels to provide them with nutrients and oxygen. This process, also known as angiogenesis, is essential for a tumor to continue to grow and to metastasize to other areas of the body. The approved treatments for the patients with advanced kidney cancer are sorafenib (Nexavar) and sunitinib (Sutent). 
 
Recent studies show that these drugs can slow the progress of kidney cancer and allow patients to live longer.
 
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.
 
What can I expect after treatment for kidney cancer?
 
After treatment for kidney cancer, routine life-long surveillance is necessary. Surveillance typically consists of periodic assessment by a physician, blood tests and X-rays. 
 
There is no standard surveillance protocol; therefore, your physician 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.
 
Do I need any additional treatment after surgery?
 
When the tumor is benign, no further therapy is needed. When the tumor is malignant, most cases can be adequately treated with surgery alone. 
 
Additional treatment (in the form of immunotherapy or anti-angiogenic treatments) may be considered when there is advanced local cancer stage, spread to the lymph nodes or metastasis to distant organs.
 
Can I live a normal life with one kidney?
 
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 kidney surgery, can I do anything to protect my 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.