Here's how the kidneys work:
Each glomerulus produces urine, which then moves through connecting tubes called tubules. The glomerulus and the tubules together form units called nephrons, each of which connects to larger tubular branches and finally to a "collection area," called the calyx. The calices form the funnel-shaped portion of the renal pelvis, through which urine moves to the ureters, the large tubes that connect the kidney to the bladder.
In addition to removing waste, the kidneys have another important function — they produce three important hormones: Erythropoietin, which triggers the production of red blood cells in bones
Renin, which regulates blood pressure
Vitamin D, which helps regulate the body's calcium, which is necessary for healthy bones
The kidneys can develop several types of cancer, though renal cell carcinoma (RCC) is the most common. RCC occurs when malignant cells develop in the lining of the kidney's tubules and grow to form one or more tumors.
Tumors discovered at an early stage usually respond well to treatment and patient survival rates are fairly high. Tumors that have become very large or spread (metastasized) through the bloodstream or lymphatic system are, of course, more difficult to treat.
Incidence and Prevalence
According to the National Cancer Institute, the highest incidence of kidney cancer occurs in the United States, Canada, Northern Europe, Australia, and New Zealand, with the lowest incidences occurring in Thailand, China, and the Philippines.
In the United States, kidney cancer accounts for approximately 3% of all adult cancers and affects nearly twice as many men as women. About 32,000 new cases are diagnosed each year, most often in people between the ages of 50 and 70 and in smokers about twice as often as non-smokers.
- Overuse of painkillers, particularly those containing phenacetin, which was removed from U.S. markets 20 years ago, but may still create a risk for older people
- Chemical exposure, particularly to asbestos and cadmium
- Genetics/ family history
- Age — RCC occurs most frequently in adults 50 - 70 years old
- Diet and weight — a high-fat diet and obesity may increase the risk for RCC
- Extended dialysis — patients treated with long-term dialysis may develop cysts in their kidneys, a risk factor for RCC
- Estrogen — test animals have developed RCC when given estrogens
- Gender — RCC occurs twice as often in men as in women
Signs and Symptoms
The primary symptoms of RCC are
- Abdominal mass or lump
- Blood in the urine
- High blood pressure
- Pain in the side or lower back
- Persistent fatigue
- Rapid, unexplained weight loss
- Swelling (edema) of the legs and ankles
If your physician suspects RCC, he or she will conduct a series of examinations to confirm the diagnosis. These tests might include Imaging tests, which provide pictures of the kidney(s), so the doctor can locate any abnormalities. Sometimes, these tests require that a dye or low-level radioactive isotope be injected into the patient's bloodstream
Computed tomography (CT scan) — a type of x-ray that provides cross-sectional, three-dimensional images of internal organs and glands to help the doctor detect tumors or enlarged lymph nodes
Magnetic resonance imaging (MRI scan)
Intravenous pyelogram (IVP) — a type of x-ray that allows the doctor to detect tumors or damage caused by tumors because the image shows a white kidney against a dark background. The x-ray is created by injecting a dye containing iodine through a vein in the arm into the bloodstream. The dye eventually collects in the urinary system, where it improves the contrast for x-rays and produces a well-defined image of the kidneys, ureters, and bladder. In some cases, the doctor may also request an arteriogram or venacavagram to check for tumors in the connecting arteries and veins
Chest x-ray — to check for any cancer that has spread to the lungs or bones of the chest
Bone scan — to check for any cancer that may have spread to the bones
Urinalysis — to check for blood in the urine
Blood tests — to screen for Anemia — too few red blood cells caused by internal bleeding and a common cancer symptom
Polycythemia — too many red blood cells, sometimes caused by cancerous tumors in the kidney
Hypercalcemia — high blood calcium levels and elevated liver enzymes
Cystoscopy — to determine where any internal bleeding originates
Fine needle aspiration — to examine a cell sample of growing tumors
Pathology — a study of tumor cells under a microscope to determine into which of four categories an RCC tumor falls. Determination of a tumor's category also helps determine how aggressive a cancer, if any, is present Clear cell — least abnormal
Granular cell — indicates a more aggressive form of cancer
Mixed clear and granular — indicates the most common form of RCC and the most aggressive form
Sarcomatoid or spindle type — indicates a form of cancer that grows and spreads quickly
The grade of a cancer cell is an assessment of its appearance compared to that of a normal, healthy cell. Grading is done on a scale of 1 to 4. Grade 1 RCC cells differ little from normal kidney cells, typically spread slowly, and have a good prognosis for treatment. Grade 4 RCC cells look extremely different and indicate an aggressive cancer with poor prognosis.
Grading and categorization of cancer cell types help determine a patient's prognosis, while a cancer's stage — a gauge of the tumor's size and location — is often used to determine a patient's chance for survival.
Many things influence a patient's treatment plan, but the main factors are age and overall health, and the extent to which the cancer has spread.
At Northern Light Eastern Maine Medical Center, we believe you should play a vital role in creating your treatment plan, and so we will carefully outline each treatment option, its side effects and its potential outcome. We know that understanding your treatment can help you maintain a positive outlook — which can improve the chances for your recovery.
Treatment options include
- Radical nephrectomy, or the removal of the entire kidney
- Partial nephrectomy, or removal of part of the kidney and any cancerous tissue
- Radiation therapy
- Hormone therapy
- Biological or immunotherapy
Sometimes a treatment plan will combine several options, like surgery to remove a primary tumor followed by radiation or chemotherapy to kill any remaining cancer cells.
Renal cell cancer is unpredictable. In about 0.5 percent of all cases, tumors regenerate after removal. Generally, the five-year survival rate for RCC — all stages combined — is about 40-45%.
Typically, RCC patients undergo follow-up examinations every three months for the first year after surgery. These examinations include a complete physical examination, chest x-ray, blood tests, and assessments of liver and kidney function.
If the disease recurs but remains confined to a limited area, additional surgery may be recommended followed by radiation, biological therapy, or chemotherapy.
Other Types of Kidney Cancer
Transitional Cell Carcinoma
Transitional cell carcinoma accounts for about seven percent of kidney cancers. It begins in the renal pelvis — the point where the kidney joins ureter — and is usually caused by cigarette smoking. Symptoms are similar to those of RCC, including blood in the urine and back pain. If found early, this form of cancer has a 90 percent cure rate, though that rate declines sharply if the cancer has invaded the ureter wall or penetrated the kidney. Regular follow-up examinations after surgery are essential since transitional cell carcinoma often recurs.
Renal sarcoma, a rare disease of the kidney's connective tissues, accounts for less than one percent of all kidney tumors. Its symptoms are similar to those of RCC: hematuria, pain in the back or flank, or a lump and mass in the abdomen.