ABOUT KIDNEY CANCER

Each kidney is about the size of an open hand and works independently to filter impurities and excess salts such as potassium and sodium from the blood. The kidneys process these wastes to generate urine. Urine is concentrated in a central funnel-like reservoir within the kidneys called the renal pelvis, also known as the collecting system. It is then passed down long, slender tubes called ureters, which connect the kidneys to the bladder.

Primary kidney cancer, also called renal cell cancer, is a malignant tumour that originates in the kidney. There are two main types of primary kidney tumours — renal cortical tumours (about 90 percent of tumours) and transitional cell (also called urothelial) tumours. Each of these tumour types arises from different parts of the kidney and requires different approaches for treatment.

Kidney cancer affects more than 2700 people in Australia each year. It occurs more often in men than in women.

ADDITIONAL INFORMATION

Types of Kidney Cancer

Each kidney contains more than a million microscopic blood-processing filtering units called nephrons. Each nephron is associated with a microscopic renal tubule, which joins several other tubules from other nephrons to form collecting ducts. These ducts deposit the urine in the renal pelvis. When cancer arises in the main part of the kidney that contains the renal tubules, it is called a renal cortical tumor. Cancer that arises in the renal pelvis is called a transitional cell (urothelial) tumor.

Risk Factors

Studies have shown that certain lifestyle factors can increase the risk of developing kidney tumours. Smoking, having high blood pressure, eating a high-fat diet, and being overweight all may contribute to an increased risk of kidney cancer. Although we do not know all the causes of kidney cancer, the following factors can also increase the risk of developing this disease:

  • long-term dialysis, a process in which a machine filters the blood of a person without functioning kidneys
  • exposure to asbestos, such as occupational exposure

exposure to cadmium, a metal that can increase the cancer-causing effect of smoking

Renal Cortical Tumours

Renal cortical tumours are a diverse group of tumour types that can exhibit very different clinical behaviours, meaning that their risk of spreading to other areas of the body varies. These tumours can be either benign (non cancerous) or malignant (cancerous). Renal cortical tumours are categorized into the following types:

  • Conventional, or clear cell, which accounts for 60 to 65 percent of cases.
  • Papillary, makes up 10 to 15 percent of cases. Papillary carcinomas can develop as individual or multiple tumours, appearing either in the same kidney or in both kidneys. There are two types of papillary cancers, type 1 and type 2. Type 1 are more common and usually grow slowly. Type 2 papillary tumours represent more than one category of disease but, as a group, are much more aggressive and may follow an unpredictable growth pattern.
Papillary carcinomas have been associated with genetically inherited syndromes, including hereditary papillary renal cell carcinoma (HPRCC) and hereditary leiomyomatosis and renal cell carcinoma (HLRCC). HLRCC is a relatively rare, inherited form of kidney cancer that is difficult to diagnose before surgery in patients without a known family history of the disease. Genetic testing is available for individuals suspected of having the syndrome.
  • Chromophobe, which accounts for 5 to 10 percent of kidney tumours. These are considered a less aggressive form of primary kidney cancer. Chromophobe tumours may reach a very large size before there is any risk of spreading outside the kidney.
  • Oncocytoma, which makes up 5 to 10 percent. Oncocytomas have almost no risk of spreading or causing death.
  • Collecting duct, which makes up less than 1 percent. This is a very rare and aggressive type of tumour that is more common in younger adults and doesn’t respond to conventional therapies for renal cortical tumours.

Unclassified, which makes up 3 to 5 percent. These rare tumours look different under the microscope than other kidney cancer subtypes and are usually very aggressive.

Transitional Cell Tumours

Transitional cell tumours of the kidneys and ureters are similar to bladder tumours. The type of cells that line the inside of the bladder also line the inside of the ureters and the renal pelvis. Cancers that arise from these cells behave similarly, whether they grow in the bladder or in the collecting system (renal pelvis and ureter). Doctors manage these lesions differently than renal cortical tumours, depending on several factors including tumour grade, location, and size.

Low-grade transitional cell (urothelial) tumours that can be reached with a thin fibre-optic scope can sometimes be treated successfully using laser energy or electrocautery (using an electrically heated needle to destroy tumour tissue). High-grade tumours represent a much greater risk, and more aggressive forms of treatment are typically recommended. Such treatment may include removal of the entire kidney and attached ureter leading down to the bladder.

With both low- and high-grade tumours, the initial diagnosis depends on both the results of imaging studies and microscopic analysis of a tissue sample. The means by which the tumour sample is obtained depends on the clinical situation

Not all masses found in the kidneys are renal cancers. Other types of masses include benign conditions such as oncocytomas, angiomyolipomas (AML), and renal cysts. Both renal cysts and AML lesions have identifiable characteristics that can be seen on imaging studies and usually do not require treatment.

Certain types of cancers from other parts of the body, such as breast, lung, and skin cancers, can spread to the kidneys. Lymphoma can also be found in the kidney. How these diseases are evaluated and treated depends on what other findings are present, including the extent of the original cancer.

Kidney cancer rarely occurs in children and young adults; the exceptions are a pediatric kidney cancer called Wilms’ tumor and some forms of hereditary kidney cancer syndromes, such as von Hippel-Lindau (VHL) disease. Patients with hereditary forms of kidney cancer often require specialized approaches to diagnosis and management, including genetic counseling and coordinated evaluation with other medical specialties.

Symptoms

Kidney cancer usually shows no symptoms in the early stages. Generally, it is not suspected until symptoms appear; by that point, the tumour may have grown fairly large. As the cancer progresses, symptoms may include some of the following:

  • blood in the urine
  • unexplained lower back pain
  • a mass or lump in the abdomen
  • fatigue
  • unexplained weight loss, which may be rapid
  • fever that is not due to a cold or flu
  • swelling of the ankles and legs

Some of these symptoms may be due to other causes, such as an infection. Your doctor can determine what is causing them and how they should be treated.

Hereditary Kidney Cancer

A family history of kidney cancer and/or certain hereditary diseases also increase the risk of kidney cancer:

  • von Hippel-Lindau (VHL) disease, a syndrome caused by a genetic mutation that leads to multiple tumours in the kidney, often at an early age, and may also include brain and eye hemangiomas, pancreatic cysts, and adrenal tumours
  • Birt-Hogg-Dubé syndrome (BHD), an inherited skin disease affecting the hair follicles and associated with kidney tumours and air pockets in the lungs
  • hereditary papillary renal carcinoma (HPRC), an inherited form of kidney cancer characterized by papillary renal cancer in younger patients, which are typically multiple and bilateral (in both kidneys)
  • hereditary leiomyomatosis and renal cell carcinoma (HLRCC), an extremely rare inherited genetic mutation in which affected individuals may have skin bumps, women often have large fibroids of the uterus that cause severe menstrual bleeding, and men and women are at risk for aggressive forms of kidney cancer
  • tuberous sclerosis, a genetic disorder characterized by severe skin bumps, seizures, mental retardation, and cysts in the kidneys, liver, and pancreas
  • Genetic testing is required to determine whether hereditary factors might increase your risk for kidney cancer.

Because kidney cancer is less common in Australia than many other cancers, there are no widely used screening programs, and regular examinations to detect it are not recommended. However, if you have been on long-term kidney dialysis or have a history of VHL or other forms of hereditary kidney cancer, you may benefit from periodic evaluation to screen for kidney tumours.

If you have a hereditary form of kidney cancer, screening studies to evaluate your family members who may also be at risk may be arranged. Identifying high-risk patients with kidney cancer can make early, curative intervention possible.

Diagnosis

Most kidney tumours are found incidentally — during an evaluation with radiologic imaging studies for other nonspecific abdominal complaints (gallbladder pain, for example), or during follow-up for other previously treated malignancies. These “incidental cancers” are often found early, before any symptoms have occurred. Because such cancers are usually detected before they have spread, patients with incidental kidney tumours are often cured of their disease, commonly by surgery alone.

Moreover, as many as 30 percent of kidney masses represent a benign condition.

If Dr Ruban suspects you have a kidney tumour, he may recommend computed tomography (CT) scanning or magnetic resonance imaging (MRI). Recently developed imaging techniques — including 3-D CT, 3-D MRI angiography (imaging of the blood vessels), and CT urography (imaging of part of the urinary tract) — reveal detailed anatomy, which allows surgery to be planned, often using a single imaging test. Ultrasound may be used when it is necessary to determine whether a kidney mass is a fluid-filled cyst or a solid tumor. To limit the radiation exposure to our patients as much as possible, we make every attempt to perform CT scans only when absolutely necessary.

If Dr Ruban suspects that you have cancer of the renal pelvis, or transitional cell carcinoma, he may perform one of the following:

  • Cytoscopy, which involves inserting a small tube with a lens into the urethra to allow the bladder and urethra to be seen;
  • Pyelogram, which involves taking an X-ray of the kidneys and ureters.

Ureteroscopy, which involves passing a narrow lighted tube through the urethra, into the bladder, into a ureter, and into the renal pelvis to look for signs of cancer.

Dr Ruban may remove a small piece of tissue (a biopsy) to examine it for cancer cells.

After surgery to remove a renal cortical tumour, the tumour cells will be examined to determine if the tumor is benign or malignant. If it is cancerous, the cell type will be determined. This information will then be used, along with the size of the tumour and other aspects of the tumour’s growth, to more accurately predict the prognosis and determine whether further treatment is necessary.

In addition to these tests, when making treatment decisions your full medical history will be taken into account, a physical examination will be performed, and blood and urine tests may be ordered.

Treatment Overview

Dr Ruban makes treatment recommendations for kidney tumours based on the specific tumour size, location, and stage of the disease — that is, how large the tumour has grown, how deeply it has invaded the kidney, and whether it has spread to nearby organs, lymph nodes, or another part of the body. Treatment may include surgery, chemotherapy, radiation therapy, or immunological therapy, alone or in combination.

The following sections provide details on kidney cancer treatments.

Surgery

Surgery is the most common form of treatment for kidney tumours, and it is often the only treatment necessary. If an operation is necessary, an evaluation based on the size and location of the tumor will be undertaken and a recommendation made either to remove the tumour (partial nephrectomy) or the entire kidney (complete, or radical nephrectomy).

Dr Ruban has expertise in both standard open surgical approaches and minimally invasive techniques for kidney cancer. His expertise in the latest laparoscopic and robotic approaches for kidney cancer were refined during his 2-year fellowship in Paris working with some of Europe’s finest kidney surgeons.

The choice of a surgical approach depends on the individual patient and his or her disease. Dr Ruban can help you make informed decisions about your treatment.

Minimally invasive surgery, which includes laparoscopic and robotic surgery, is done through small incisions in the abdominal wall using a camera that transmits images to a video monitor. This approach can, in most cases, reduce the time it takes to recover after surgery.

When advanced kidney tumours have spread to adjacent organs, surgeons who specialise in the affected area are involved in treatment. Vascular surgeons are available when the cancer has spread to the arteries, veins, and smaller vessels, while thoracic (chest) surgeons may be called on to remove a tumour that has spread to the lungs.

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Partial Nephrectomy

Kidney-sparing (or nephron-sparing) surgery is a procedure in which a kidney tumour is removed, leaving a margin of normal kidney tissue in order to preserve the function of the remaining kidney. Studies have demonstrated that partial nephrectomy yields comparable results to complete nephrectomy in patients with small tumors (less than 4 cm), while maintaining functioning kidney tissue.