Because many people older than 40 have back pain, this symptom is often ignored. Consequently, RCC can go undiagnosed or be misdiagnosed until it has spread (metastasized) elsewhere. At the time of diagnosis, 15 to 25 percent of kidney cancer patients have metastatic RCC.
Several tests are used to diagnose kidney cancer. First, physicians will feel the abdominal area for lumps or masses and may order an intravenous pyelogram (IVP) X-ray. An IVP requires doctors to inject a dye containing iodine into the bloodstream so they can see the kidney more clearly during the X-ray.
Arteriography is also used to find growths in the kidney. Doctors first inject a contrast dye into an artery leading to the kidney and then take an X-ray. This highlights the blood vessels nourishing the tumor and helps surgeons plan the best way to remove the cancer.
The patient may need additional imaging tests to determine the extent of the cancer. In CT scanning, a computer combines several X-rays to create a cross-section image of the inside of the body. Magnetic resonance imaging employs a strong magnet and electromagnetic energy to provide a similar but more detailed picture. In ultrasound, sound waves are used. Chest X-rays and bone scans help determine if the cancer has metastasized.
Lab tests may include urinalysis because about 50 percent of patients with RCC will have blood in their urine. Urinalysis can find even small amounts of blood. Sometimes, urine cytology, a microscopic examination of urine samples, will reveal cancer cells in the urine. Blood in the urine may come from an organ other than the kidneys, so doctors may use cystoscopy to determine whether blood is coming from the urethra, bladder or kidney.
In this test, a lighted tubular instrument called a cystoscope is inserted into the bladder via the urethra to visually examine the inside of the organ. Small tumors can sometimes be removed through the tube, or brushes may be inserted to collect cells for examination. The procedure is performed under general or local anesthesia. The urethra may swell after a cystoscopy.
Blood tests can detect conditions associated with kidney cancer such as a deficiency of red blood cells (anemia) or an excess of red blood cells (polycythemia). Polycythemia can occur because some renal carcinoma cells produce a hormone that increases the red blood cell formation. Blood tests can also detect high levels of liver enzymes or calcium (hypercalcemia), which are occasionally related to RCC.
On rare occasions when imaging tests do not provide enough information, doctors may use fine needle aspiration (FNA) to help diagnose RCC. A thin needle is injected into a kidney tumor to remove fluid or small pieces of tissue for examination under a microscope. CT scans help the physician guide the needle into the tumor.
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