Several types of cancer can develop in the kidneys. Renal cell carcinoma is the most common form, accounting for about 85 percent of all cases. It produces cancer cells in the lining of kidney tubules that grow into a tumor. In most cases, a single tumor develops, though more than one can develop in one or both kidneys.
About 6 percent to 7 percent of kidney cancers begin in the renal pelvis, the point where the kidney joins the tube that carries urine to the bladder. These tumors, known as transitional cell carcinomas, are made of cancer cells different from renal cell carcinoma. Research indicates transitional cell carcinomas are caused by smoking.
Early diagnosis of kidney cancer is crucial in determining patients’ chances for survival. Tumors discovered at an early stage often respond well to treatment, and survival rates are high. Tumors that have grown large or spread through the bloodstream or lymphatic system to other parts of the body are more difficult to treat and present an increased risk for mortality.
What are the symptoms?
Primary symptoms of renal cell carcinoma include:
Transitional cell carcinoma symptoms are similar and include blood in the urine, known as hematuria, and pain in the back or side.
What are the treatment options?
Several factors determine the best treatment option for kidney tumors, including the patient’s age and overall health, along with the extent to which the cancer has spread. Treatment options include:
Two or more treatment types may be combined, such as surgery to remove a primary tumor followed by radiation therapy or chemotherapy to kill cancer cells that may remain in the body.
Surgery is the standard treatment for renal cell carcinoma. There are several options, depending on the stage of the disease and the overall health of the patient. With a radical nephrectomy, the surgeon removes the entire kidney and adrenal gland, and possibly some of the surrounding tissue and nearby lymph nodes, depending on how far the cancer has spread. With smaller tumors confined to the top or bottom portion of the kidney, partial nephrectomy may be performed to remove part of the kidney. This procedure also may be used for patients with renal cell carcinoma in both kidneys and for patients with only one functioning kidney.
A procedure known as arterial embolization may be used when patients are unable to undergo surgery, such as those with severe heart disease. A catheter is inserted into the artery in the groin that supplies blood to the cancerous kidney. A material is inserted through the catheter to cut off the blood supply, destroying the tumor and the kidney. If the patient is able to undergo surgery at a later date, the kidney is removed.
Surgery may result in a number of complications, including:
Tumor regrowth occurs in about 0.5 percent of cases. Once metastasis occurs, patients’ prognosis depends on the extent of the spread and the interval between kidney removal and the appearance of the metastasis. Overall, the five-year survival rate for renal cell carcinoma – all stages combined – is about 40 percent to 45 percent. If the disease recurs and remains confined to a few small areas, additional surgery may be recommended. Radiation therapy, biological therapy or chemotherapy may be combined with surgery to relieve symptoms.
Chemotherapy uses chemicals to destroy cancer cells. Unfortunately, renal cell carcinoma has proven to be particularly resistant to chemotherapy. Research to develop more effective chemotherapy drugs to treat renal cell carcinoma is ongoing, and several are being tested.
Certain drugs approved by the FDA to treat advanced renal cell carcinoma may slow disease progression and increase patients’ survival time. They should be used with caution with patients with high blood pressure, heart or liver problems, bleeding disorders or other kidney problems. Chemotherapy side effects include rash, fatigue, mouth sores, diarrhea and nausea.
Radiation therapy uses high-energy beams to shrink tumors and destroy cancer cells. External-beam radiation therapy uses a focused beam projected into the body.
Radiation therapy alone has a relatively low success rate in treating renal cell carcinoma, and often produces side effects, including diarrhea and nausea, fatigue, headaches, lung and respiratory problems and skin irritation.
Radiation therapy is used often as a follow-up treatment to destroy cancer cells that remain in the body after a radical or partial nephrectomy, in which all or part of the kidney is removed. Radiation therapy also may be used to lessen pain or bleeding in patients with inoperable or widespread metastatic renal cell carcinoma. In such cases, there is no expectation of a cure. Treatment is meant to ease the patient’s discomfort.
Radiosurgery for kidney tumors is noninvasive, and typically carries less risk of complications than conventional surgery. For patients who refuse surgery or have medically inoperable kidney tumors, radiosurgery can be an effective treatment option. CyberKnife, which delivers high-dose radiation over one to five treatments, can be particularly effective for treatment of small kidney tumors. CyberKnife has the ability to compensate for normal patient movements, precisely targeting the tumor during the entire procedure and minimizing damage to surrounding healthy tissue. This is important when treating kidney tumors, which can shift during treatment due to regular patient movements such as breathing. Radiosurgery treatment with CyberKnife also can be an effective option for treating renal cell carcinoma metastases to the spine, which are not uncommon.