Kidney Cancer

Figure 1

The kidneys are the two bean shaped organs situated in the loins (figure 1). Their main function is to filter blood and produce urine to rid the body of waste products. Urine first collects in the central portion of the kidney (renal pelvis) and then drains through a long tube structure called the ureter into the bladder.

Several types of cancer can develop in the kidney. The most common is renal cell adenocarcinoma which develops in the portion which filters blood and produce urine. The other variety which develops in the urine collecting portion (pelvis) – transitional cell cancer is less common. In childhood, a different type called Wilms’ tumour can occur. This article will deal with the most common renal cell adenocarcinoma only.

Kidney cancer starts as a small focus within the kidney tissue and produces no symptoms at this stage. As the cancer grows inwards, it will reach the pelvis. Outwards, it will deform the kidney surface and even invade the surrounding fat, organs nearby like liver, colon, spleen or pancreas. Lymph nodes along the main artery and vein of the kidney may also be involved signifying advanced disease. Distant metastases to most commonly lungs and bones can occur.

Causes:

Most of the renal cancers develop without any obvious cause. In a small number of patients, the cancer runs in the family. People who have an inherited disorder called Von Hippel Lindau disease are also at a greater risk of developing renal cell carcinoma. Patients on long term use of dialysis to treat chronic renal failure have an increased risk of developing renal cysts and renal cancer.

Symptoms:

In the early stages, kidney cancer produces no symptoms. But as the cancer grows and becomes larger the following symptoms may occur:

Blood in the urine (haematuria)- either gross or microscopic, may occur. A mass in the kidney area may be felt by the patient himself. Pain can occur in the loin which is usually persistent. Other symptoms include weight and appetite loss, recurrent fevers, tiredness and hypertension.

Diagnosis:
When a patient complains of the above combination of symptoms, the doctor will perform a physical examination to look for lumps in the loin area. Urine testing is very important to detect presence of blood cells. A very useful test is the renal ultrasound which can be done in the office to detect abnormal mass lesions within the kidney. These days, more and more kidney cancers are picked up incidentally when patients had ultrasound scans to look for other abnormalities in the abdomen.
Thankfully, these incidental cancers tend to be smaller and easier to manage.

Most of the time, your consulting doctor will order an Intravenous Urogram study to outline the kidney anatomy, function and its collecting system.

If blood is present in your urine, your doctor will order an Intravenous Urogram (IVU) study to outline the kidney anatomy and exclude other causes of bleeding. The next most important test is CT scan which will show the abnormal mass (figure 2)within the kidney very well. The surrounding tissues, lymph nodes can also be assessed to help determine how far on the tumour has grown. Usually, the CTscan appearance of a kidney cancer is so obvious that no further sophisticated investigations require to be done.

Figure 2

A renal biopsy (introduction of a needle through the skin into the kidney tumour for sampling a piece of tissue) done under ultrasonic or CTscan guidance is not often indicated as most abnormal solid appearing masses in the kidney are usually malignant in nature. There is a slight theoretical risk of seeding tumour cells along the needle track.

Kidney cancers have a tendency to extend into the veins and even into the main abdominal vein (inferior vena cava). Usually, CT scan will reveal any spread into the renal vein but an MRL examination is called for when the urologist need to assess the inferior vena cava more accurately.

Nowadays, renal angiograms (a special X-ray of the blood vessels of the kidney) are rarely performed for diagnosis of kidney cancers.

A chest X-ray is also important to rule out spread to the lungs especially in large tumours.

Treatment:

Treatment for kidney cancer depends on the stage of the disease, patient’s general health and age and other factors. Surgical extirpation by removal of the kidney, adrenal gland and surrounding fat tissue (radical nephrectomy) is the most common treatment for larger kidney cancers (figure 3). In the event that the tumour is still localised within the kidney, nephrectomy can be curative.

Figure 3

When the tumour is small the urologist may sometimes suggest an operation to only remove part of the kidney bearing the tumour (partial nephrectomy). This type of operation has the advantage of preserving kidney function and would be the operation to consider if the patient has only one kidney which has a tumour in it or has impaired kidney function.

Interruption of the blood supply to the affected kidney (renal arterial embolisation) is sometimes considered before an operation to shrink a very large and vascular tumour to make surgery easier. It may also be used to stop troublesome bleeding from the tumour when nephrectomy is not possible. These procedures are carried out by the specially trained radiologist. The radiologist will use pieces of special gelatin sponge or other material injected through a catheter to clog the main renal blood vessel.

Radiotherapy is ineffective to cure the primary kidney cancer and is used more often to treat recurrence after nephrectomy or painful secondary lesions to bones.

In patients who have disseminated kidney cancer, the prognosis is not good. Various therapies can be employed but all have limited effectiveness. Chemotherapy with Vinblastine can be tried. Hormone therapy using progesterone is tried in a small number of patients with advanced disease but usually as palliation. Biologic therapy (immune modulation therapy) using Interferon or Interlelukin-2 have been proven to be effective in shrinking limited volume metastatic tumours. The therapy is quite expensive and may have side effects presenting as fever, tiredness, weakness and loss of appetite. These problems can be severe but go away after cessation of therapy. Research into gene therapy may hold some promise in the future for kidney cancer.

Regular follow-up by the urologist is important after any treatment for renal cancer. Appropriate investigations using physical examination, x-rays and blood tests may be done.