What is kidney cancer?
Cancer is the uncontrolled growth of cells within the body. Usually, all of our cells have a specific lifespan of days to years that is genetically programmed in our DNA. When our DNA becomes damaged, either through the aging process, exposure to toxins such as radiation or chemicals or through inherited genes, some cells do not die a natural death but continue to grow. As they do, they form new cells with the same genetic misinformation. These extra cells may form masses or tumours that can be either malignant or benign. A benign tumour is a tumour that does not invade the surrounding tissue or spread around the body and stays in one place. A malignant tumour can invade the surrounding tissue or spread via the blood or lymph networks and affects other cells and organs.Â
Only approximately 2% of people develop renal cancer, with renal cell carcinoma the second most common form in adults. Most kidney cancer is first diagnosed after the appearance of blood in the urine or unexplained back or flank pain. Early diagnosis usually happens where kidney cancer has run in families and a decision has been made to undergo regular screening. The deep position of the kidneys makes it difficult to feel a lump and there is, as yet, no screening program for this disease.
Not everyone who has kidney cancer or renal cancer will develop kidney disease and not everyone who develops kidney disease will develop kidney cancer, although these diseases are linked. Treatments for kidney cancer are primarily aimed at tumour removal and preventing further growth, as well as treating symptoms.
Are there different types of kidney cancer?
There are various forms of kidney cancer and your medical notes may be difficult to understand. Most specific types are based upon the location and type of abnormal cells.
Renal cell carcinoma
About 85% of kidney cancers are renal cell carcinomas that begin in tiny tubules inside the kidneys responsible for filtration of toxins, by-products and excess water.
Urothelial carcinoma or transitional cell carcinoma
Urothelial carcinoma is the second most common type of kidney cancer that starts in an area of the kidney known as the pelvis. This is where urine gathers before moving out of the kidney, through the ureter and into the bladder. Urothelial cells of the bladder and pelvis are similar and are usually treated in the same way.
Kidney sarcoma
A thin layer of fat surrounds the kidney and, very rarely, is the site of cancerous cells. This type of cancer always requires surgery and can recur. Surgical procedures are usually followed by chemotherapy.
Wilms’ tumour
Wilms’ tumours are most common in children but are still extremely rare. Treatments may require surgery but often respond extremely well to radiation treatment and chemotherapy.
Kidney cancer stages
Your medical notes may have listed a number of codes concerning your kidney cancer diagnosis. Or perhaps you are waiting for further testing and prefer to be well-informed before receiving your results.
The majority of oncologists and urologists adhere to the universal TNM staging system. In short, this system uses a scoring system for tumour, (lymph) nodes and metastasis according to biopsy and imaging results.
T stands for tumour. T plus a letter or number describes the size (in centimetres) and location of a tumour. Where more than one tumour is present, the letter ‘m’ (multiple) is added. T letter and number systems for kidney tumours are:
TX: It is not possible to evaluate the tumour due to a lack of data
T0: No evidence of a primary tumour
T1: The tumour is local to the kidney and 7 cm or smaller
T1a: The tumour is local to the kidney and 4 cm or smaller
T1b: The tumour is local to the kidney and between 4 cm and 7 cm
T2: The tumour is local to the kidney and larger than 7 cm
T2a: The tumour is local to the kidney and between 7 cm and 10 cm in size
T2b: The tumour is local to the kidney and greater than 10 cm in size
T3: The tumour has grown into the major veins inside the kidney or the fatty tissue around the kidney but not into the adrenal gland or the fascia surrounding the kidney
T3a: The tumour has spread into the renal vein or its branches; or the fatty tissue around the kidney; or the pelvis and calyces of the kidney. The tumour has not grown beyond the fascia
T3b: The tumour has grown into the inferior vena cava below the diaphragm
T3c: The tumour has spread to the vena cava above the diaphragm and into the right atrium of the heart
T4: The tumour has spread to areas beyond the kidney fascia, extending into the adrenal gland
N stands for nodes or lymph nodes and the following codes apply:
NX: Regional (nearby) lymph nodes cannot be evaluated due to lack of data
N0: No spread to regional lymph nodes
N1: Tumour has spread to regional lymph nodes
Finally, M stands for metastasis. Only two codes apply:
M0: There is no spread to distant lymph nodes or other organs
M1: Distant metastasis is present in distant lymph nodes and/or to other organs.Â
Kidney cancer metastasis (M1) is most likely to affect the lungs, bones, liver, and/or brain.
What are kidney cancer symptoms?
If you are reading this page, you may have been diagnosed with kidney cancer due to the presence of one or more symptoms.
Symptoms usually occur when a kidney tumour has grown and exerts pressure on the filtration units or other areas of the kidney that stop one of the kidneys from working properly. As we only need one kidney, you will probably not experience any differences in urine output. The most common symptoms of kidney cancer are:
Blood in the urine
Loss of appetite and weight loss
Unexplained unilateral flank or back pain
A continuous, unexplained fever
Swelling in the lower limbs
Fatigue
Anaemia
Can I prevent kidney cancer?
There are a number of ways in which you can lower the risk of developing renal cancer. Smoking doubles the risk and this habit should be stopped. Being male also increases the risk of developing the disease.Â
Other risk factors are obesity, high blood pressure, long-term medication use (especially over-the-counter painkillers), a diagnosis of renal disease, kidney transplant patients on long-term therapies and patients receiving long-term kidney dialysis. A handful of genetic conditions and a positive family history (especially brother/sister) increase the risk of developing renal cancer.
Furthermore, certain types of work where continuous exposure to chemicals such as benzene, solvents, herbicides and asbestos can also increase risk.
If you are able to make lifestyle changes, you may be able to lower your risk of developing kidney cancer. Alternatively, if you have a positive family history, opting for regular screening can catch renal cancer in its early stages where subsequent treatment can often be curative.
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