By Dr Ananya Mandal, MD
Kidney cancer or renal cancer is the eighth most common cancer in adults in the UK and accounts for 2% of all cancers in the U.S.
What are the kidneys?
The kidneys are two small bean-shaped organs located on either side of the body, just underneath the ribcage. The main role of the kidneys is to filter out waste products from the blood and to produce urine.
What causes kidney cancer?
Usually, only one of the kidneys is affected by cancer. Cancer occurs when the growth, maturity and division of normal cells are deranged and there is uncontrolled proliferation of the cells to form a tumor.
Kidney cancer epidemiology
In the Western countries kidney cancers account for 2-3% of all cancers. Males are more likely to be affected than females, with a ratio of 1.5:1. The incidence rises with age after 40 and the risk is highest in people aged between 60 and 70 years.
In the UK there has been an increase of 22% over 10 years while in the USA there has been an increase of 50% in 30 years. Obesity as a risk factor is suggested to be a cause of this rise in numbers of cases.
Risk factors for kidney cancer
Several risk factors have been identified. The risk factors for renal cancers include:
Cancers that are inherited and run in families are usually multiple, affect both kidneys and occur at an earlier age than others. However, 2% of cases may affect both kidneys as well.
Signs and symptoms of kidney cancers
One of the early symptoms includes presence of blood in urine, pain under the ribs and in the flanks and feeling a lump within the abdomen. In around half of the cases especially in early stages these symptoms may be absent and the cancer may be detected during tests for other unrelated conditions.
Types of kidney cancer
There are a number of different types of cancer than can affect the kidneys. The commonest type is the renal cell carcinoma (RCC), which accounts for more than 80% of all kidney cancers. Other types include transitional cell cancer that develops in the lining of the kidneys and affects middle aged persons. There is also Wilm’s tumor that is a rare type of kidney cancer that affects children.
Treatment of kidney cancers
The treatment of kidney cancer depends on the stage of the cancer and its spread to other organs. Surgery is usually the first course of action and involves removal of the tumor as a whole.
Chemotherapy is not very effective in treating kidney cancer. Radiation therapy and targeted drug therapies are used especially when the kidney cancer is advanced and has spread beyond the kidney.
Outlook or prognosis
The prognosis or outlook of kidney cancer is good if the cancer is detected at an early stage when it is still confined within the kidney. This is because removal of the cancer is possible with surgery at this stage. In most cases only one kidney is affected and it is possible to live a healthy life with only one kidney.
One third of all kidney cancers are detected at an early stage. 65-90% of people will live at least five years after receiving an early diagnosis of kidney cancer and many live much longer.
For those detected at more advanced stages 40-70% will live at least five years after receiving a diagnosis.
If the kidney cancer is advanced and spread to other parts of the body, a chance of five year survival is around 10%.
Reviewed by April Cashin-Garbutt, BA Hons (Cantab)