The paired kidneys are located on either side of the spine, partially under the rib cage in back. These vital organs are composed of many tiny tubules that filter waste products out of the blood. The waste (urine) travels from each kidney to the bladder through a muscular tube called a ureter. Urine passes out of the body from the bladder via another tubular structure, the urethra. The kidneys serve additional vital functions including stimulating red blood cell growth, balancing fluids,salts (electrolytes), and assisting with blood pressure control.
Frequency of Kidney Cancer
Kidney Cancer is the 7th most frequent cancer (8th in women) and 10th most common cause of cancer death. In the United States in 2009, nearly 50,000 new cases of kidney cancer were diagnosed and just over 11,000 deaths resulted from this disease. The incidence of kidney cancer has been rising gradually since the 1970s, attributable at least in part to improved early detection by increased use of radiographic imaging..
Risk Factors for Developing Kidney Cancer:
- Smoking: Cigarette smokers are twice as likely as nonsmokers to develop kidney cancer.
- Obesity: People who are obese have an increased risk of kidney cancer.
- High blood pressure: High blood pressure increases the risk of kidney cancer.
- Dialysis Long-term: Dialysis is a treatment for people whose kidneys do not work well. It removes wastes from the blood. Being on dialysis for many years is a risk factor for kidney cancer.
- Von Hippel-Lindau (VHL) syndrome: VHL is a rare genetic disease, caused by alteration of the VHL gene. In addition to the high risk of kidney cancer, these families are also at risk for cysts or tumors in the eyes, brain, pancreas, and adrenals. Family members of known VHL patients can be tested to see if they carry the abnormal VHL gene. For people with the abnormal VHL gene, doctors may suggest imaging studies to aid in early detection of kidney cancer and other diseases.
- Family History: Besides VHL, several other familial genetic conditions predispose to kidney cancer. These include
- Occupation: Some people have a higher risk of getting kidney cancer because they come in contact with certain chemicals in their workplace. Coke oven workers in the iron and steel industry are at risk. Workers exposed to asbestos or cadmium also may be at risk.
- Gender: Men are almost twice as likely as women to be diagnosed with kidney cancer.
Diagnosis of Kidney Cancer
Over the last two decades, kidney tumors have been found increasingly on imaging performed for some other reason. For example, abdominal ultrasound may be performed to evaluate abdominal pain, or MRI may be used to evaluate back pain, but either may also identify a kidney mass. CT scans performed in the emergency room after trauma or for a variety of other conditions have found an increasing percentage of kidney cancers since CT has become widely available.
Any solid enhancing mass is highly suspicious for cancer. There are several relatively rare benign renal masses, but these are difficult to differentiate by how they look on ultrasound, CT, or MRI. Kidney biopsy is occasionally useful to determine the origin of a kidney mass. For example, in a patient who has had another type of cancer, biopsy of an unusual kidney mass can help prevent surgery that is unlikely to provide benefit. Most of the time, however, biopsy of a kidney mass is not helpful. If a tumor in the kidney looks like a kidney cancer, then a positive biopsy only confirms what is already believed. In that same person, a negative biopsy only raises some doubt, but does not conclusively rule out cancer. For that reason, many people in relatively good health, will still opt to have a kidney tumor treated, even after a negative biopsy. Finally , a kidney biopsy is not without risk, so if it is unlikely to alter management, it may be best avoided.
Prior to the modern use of radiographic imaging, kidney cancer was most often brought to attention by the symptoms it caused. Blood in the urine (hematuria), flank pain, or a flank mass on physical exam would prompt an evaluation. Because of the location in the body, a mass in the kidney is usually not identifiable by these means until it has enalrged over years. Therefore, kidney cancers that are found due to symptoms are usually quite large and have often spread (become metastatic) to other parts of the body. With current treatment options, kidney cancer is generally not curable once it has become metastatic.
Overview of Kidney Cancer Treatment:
Until recently, when a kidney mass was identified, the entire kidney would almost always be surgically removed. While this is still sometimes necessary to remove an entire kidney, it is better to remove the tumor and leave as much of the normal kidney as possible. The problem is that many people have medical conditions that place them at risk of kidney failure over time. The most common medical conditions that injure the kidneys over time are high blood pressure (hypertension) and diabetes. Dialysis centers are busy providing blood-filtering services for patients with kidney failure, most of whom still have both kidneys. Patients at risk, who have an entire kidney removed are at greater risk of needing dialysis. Of course, many people do fine with a solitary kidney. Evidence of this is that many people donate a kidney to someone else and live essentially normal lives. But people who are at risk of renal insufficiency as they age, such as those with diabetes and high blood pressure, need to preserve as much functioning kidney tissue as possible, in order to remain off dialysis, or at least delay it as long as possible.
Nephron-sparing surgery continues to be underutilized, because many urologic surgeons are not trained to perform the technically more difficult operation.
Radical nephrectomy is indicated when nephron-sparing surgery is not feasible. This depends greatly on the training and skills of your urologic surgeon.
In some cases, surveillance with occasional imaging studies is a reasonable option, particularly if the tumor is small or if the person has multiple medical problems that make surgery higher risk.
Treatment Options for Kidney Cancer:
Partial Nephrectomy (remove the tumor with a margin of normal tissue, leaving most of the kidney in place)
- da Vinci Robotic Partial Nephrectomy - advanced technology for difficult
- Laparoscopic Partial Nephrectomy - excellent option to remove small tumors on the periphery of the kidney.
- Open Partial Nephrectomy - Some people that have extensive abdominal surgery or can not tolerate laparoscopy due to lung or heart problems may be best served by surgery through a standard incision.
Radical Nephrectomy (remove entire kidney, adjacent adrenal gland, any enlarged lymph nodes)
- Open Surgery - an 8-10" incision is made under the rib cage or in the flank, through which the kidney is removed
- Laparoscopic - the same surgery is performed through several 1/2" incisions, using long skinny instruments and a video camera. At the conlusion of the operation, one of the incisions can be enlarged just enough to remove the kidney intact, or else it can be pulled out in pieces
Tumor Ablation (use of an energy source to destroy the cancer, but without removing the tissue)
- Cryotherapy - usually performed laparoscopically with ultrasound assistance, the tumor is identified, then frozen to destroy the cancer cells. While generally quite effective, the downside of "cryo" is that a mass continues to seen on imaging studies and can cause years of anxiety.
- Radio Frequency Ablation (RFA) - another energy source used to cook the tumor to destroy it. Some recent evidence suggests RFA is less effective than cryoablation.