Normally people have two kidneys located in the upper back on the right and left side. The typical adult kidney weighs 150 grams in men and 135 grams in women. The kidney's primary function is filtration of excess water, salt and waste products from the blood stream. The kidneys play an important role in regulating blood pressure and controlling the supply of calcium. In addition, the kidney makes a factor, call erythropoetin, responsible for stimulating producting of red blood cells.
Most commonly kidney tumors aremalignant or cancerous. Kidney cancer occurs whennormal kidney cells begin to grow uncontrollably. There are four main types of kidney cancer: clear cell, sarcomatoid, chromophobe and papillary. Clear cell is the most common type of kidney cancer and sarcomatoid is the most aggressive (the most likely to spread beyond kidney to other parts of the body). Benign tumors include: angiomyolipoma and oncocytoma. These non-cancerous tumors are considered benign since they do not have the capacity to grow beyond the kidney to other sites ni the body.
It is estimated that in the United States during the year 2001, 30,000 people will be diagnosed with kidney cancer. Kidney cancer is the 8th and 10th most common non-skin cancer among American men and women, prospectively. Kidney cancer accounts for 2 - 3% of all cancer-related deaths in the United States.
Common symptoms related to kidney cancer include: hematuria (blood in the urine), a mass and/or pain in the flank, newly developed left-sided varicocele (swelling of veins around the testicle). Although these symptoms can be caused by kidney they are all non-specific and are usually associated with non-cancerous processes. Typically patients with kidney cancer have no symptoms and are detected incidentally by a radiographic imaging study of the abdomen obtained for unrelated reasons. The best test to diagnose kidney cancer is a contrasted CT scan of the abdomen. MRI and ultrasound exams are other commonly used tests. Since these radiographic studies are so good at diagnosing kidney cancer, a biopsy of the tumor is rarely indicated.
Patients who are affected with Von Hippel Lindau disease, hereditary papillary renal cell carcinoma or Birt Hoge Dube are far more likely to get kidney cancer. These people typically develop multiple tumors in both kidneys. There is also a familial form of kidney cancer in which several family members develop the typical form of kidney cancer. Otherwise kidney cancer is not inherited and most patients with kidney cancer are not likely to "pass it on" to their offspring.
Since convential chemotherapy and radiatoin are not effective for kidney cancer, the only curative therapy involves surgical removal of the tumor. Historically the standard treatment for kidney cancer was radical nephrectomy (removal of the entire kidney and adrenal gland). Today the adrenal gland is only removed for tumors that are located in the upper portion of the kidney or involve the adrenal gland. Tumors that are smaller than four centimeters can usually be traeted with a partial nephrectomy (removal of the portion of the kidney that contains the tumor while leaving the remainder of the unaffected kidney intact). For patients with a solitary kidney or kidney failure, a partial nephrectomy is performed for tumors larger than four centimeters when a sufficient amount of the unaffected kidney can be preserved.
Today most radical nephrectomies are performed by a laparoscopic technique. During laparoscopic procedures, surgeons operate using a camera and instruments placed through small holes in the patient's abdomen. The surgical team views the procedure on a television screen. The kidney specimen can be removed after placing it in a protective bag and breaking it up into multiple small pieces. Alternatively, the inteact specimen can be removed through a small non-muscle cutting incision. The advantage of laparoscopic kidney removal to the patient over standard open radical nephrectomy include: less pain, shorter recovery time and better cosmesis (i.e. much smaller scar). Typically patients stay in the hosptial 1 - 2 days following laparoscoic nephrectomy and return to normal activity within 2 - 3 weeks. Several studies have shown that laparoscopic nephrectomy for kidney cancer provides the same opportunity for cure as does conventional open radical nephrectomy.
The standard treatment for metastatic kidney cancer (kidney cancer that has spread beyond the kidney to other parts of the body) is immunotherapy (induces the body to fight off cancer in the same way that it fights off infection). The most effective and commonly used form of immunotherapy is IL2. Other therapies including interferon gamma are used alone or in combination with IL2. It is believed that in most cases immunotherapy is more effective after the primary kidney tumor has been surgically removed.
- UNC Lineberger Comprehensive Cancer Center
- American Cancer Society
- National Cancer Institute
- Kidney Cancer Association
- Cancer Net