Understanding kidney cancer: risk factors, symptoms and treatment

Kidney cancer is the seventh most common type of cancer in the UK, with around 13,300 new cases diagnosed each year. It refers to the abnormal growth of cells that make up your kidneys — two bean-shaped organs that sit near the middle of your lower back. Here we’ll discuss its symptoms, types, treatments, outcomes and risk factors. 

Symptoms of kidney cancer

Most cases of kidney cancer are picked up incidentally before you notice any symptoms, usually through an ultrasound scan for an unrelated health condition. 

When symptoms become apparent, you may notice blood in your urine (haematuria), a lump or swelling in your back under your ribs, pain around your ribs, waist or groin area that doesn’t get better, loss of appetite, unintentional weight loss, fatigue, a persistent fever and night sweats. 

Types of kidney cancer

There are several types of kidney cancer, of which the most common in adults is renal cell cancer, also known as renal cell adenocarcinoma — around 80 in every 100 cases of kidney cancer are renal cell cancer.

Renal cell cancer can be further categorised into several subtypes: clear cell, papillary, chromophobe and sarcomatoid renal cell cancer. Of these, clear cell renal cell cancer (ccRCC) is the most common type, accounting for around 70–80 of every 100 cases of renal cell cancer. 

Other types of kidney cancer, which are less common than renal cell cancer, include renal sarcomas, upper urinary tract urothelial cancer (previously known as transitional cell carcinomas) and Wilms tumours (nephroblastomas) — Wilms tumours largely occur in children.

Stages and grades of kidney cancer

Kidney cancer can be categorised according to how similar the cancer cells are to healthy cells, which is called the grade, how large the tumour is and whether/how far it has spread, which is called the stage. 

Grades of kidney cancer

For the most common type of kidney cancer, renal cell cancer, a grading system from one to four is used for clear cell and papillary renal cell cancer. There is currently no agreed grading system for chromophobe renal cell cancer. 

Grade 1 refers to cancer cells that most closely resemble healthy cells, while grade 4 refers to cancer cells that appear most different from healthy cells. 

In most cases, the higher the grade of kidney cancer, the faster the cancer cells grow and the more likely the cancer will spread to other parts of your body. 

Stages of kidney cancer

Kidney cancer can be categorised into four stages, where stage 1 refers to early-stage kidney cancer and stage 4 refers to advanced kidney cancer. 

In stage 1 kidney cancer, the tumour is seven centimetres wide or smaller and is limited to inside the kidney. In stage 2 kidney cancer, the tumour is more than seven centimetres wide and is limited to inside the kidney. 

In stage 3 kidney cancer, the tumour has spread into the fatty tissue around the kidney or into the main blood vessels near the kidney, specifically the renal vein or vena cava, but it has not spread through the capsule that surrounds the kidney. It may have spread into nearby lymph nodes. 

In stage 4 kidney cancer, the tumour has spread through the capsule that surrounds the kidney and into nearby areas, which may include lymph nodes, or it has spread to other areas of the body (eg the liver, lungs or brain). 

Causes of kidney cancer

The exact cause of kidney cancer isn’t known, but there are many risk factors that increase your likelihood of developing it. 

Kidney cancer is more common as you get older, with around a third of cases occurring in those aged 75 and over. It is also more common in men and if you have inherited a genetic fault in certain genes. 

These genetic faults result in several different but rare inherited conditions, such as Von Hippel-Lindau syndrome, tuberous sclerosis complex and Birt-Hogg-Dubé syndrome, all of which increase your risk of kidney cancer. Hereditary papillary renal cell cancer is also caused by an inherited genetic fault. 

Environmental and lifestyle factors can increase your risk of kidney cancer too. These include smoking, being overweight or obese, exposure to ionising radiation (eg radiotherapy) or repeated exposure to certain harmful chemicals (eg arsenic and cadmium, which are used in mining, farming, painting, welding, etc).

Your risk of developing kidney cancer is also slightly raised if you have a family history of the disease, that is, a first-degree relative (parent, sibling or child) who has had kidney cancer. 

High blood pressure and diabetes also increase your risk. 

Getting a diagnosis

To reach a diagnosis of kidney cancer, you will usually need to have several tests, including a blood test, urine test and imaging tests, such as an ultrasound scan, CT scan and/or MRI scan. 

These tests are usually enough to diagnose kidney cancer. However, in some cases, particularly if non-surgical treatments such as radiofrequency ablation or cryotherapy are being considered, a tissue sample (biopsy) may be taken. 

Treating kidney cancer

Treatment for kidney cancer depends on the type, stage and grade of kidney cancer you have. Your treatment options will be discussed with a multidisciplinary team to ensure the most appropriate options are presented to you. 

In certain cases, where the cancer is very small and slow-growing, and consequently not causing any symptoms, you may not need any treatment. Instead, your cancer will be closely monitored with regular ultrasound scans and CT scans. 

In cases where treatment is needed, you may need surgery to remove part or all of your kidney and/or other therapies. 

Surgery 

Surgery for kidney cancer can be carried out as an open, keyhole or robotic procedure. 

A partial nephrectomy, where only part of your kidney is removed, is often recommended if there is cancer in both kidneys, you only have one kidney or your tumour is in one kidney and is less than four centimetres wide. 

In most other cases, a radical nephrectomy, where the whole kidney is removed, is usually recommended. 

Non-surgical treatments

If you have a small tumour in one kidney, your doctor may recommend cryotherapy or radiofrequency ablation. Both involve inserting a needle through your skin and into your kidney. 

In cryotherapy, a cold gas is passed through the needle, which kills the surrounding cells by freezing them. In radiofrequency ablation, radiofrequency energy kills the surrounding cells by heating them up. Radiofrequency ablation is also used to treat multiple tumours in one or both of your kidneys. 

If you have advanced kidney cancer or have had surgery to remove your tumour but the risk of the cancer returning is high, you may have targeted therapy or immunotherapy. 

Immunotherapy helps your immune system recognise and attack cancer cells, while targeted therapy targets proteins that help cancer cells grow in number and spread.

Treatment outcomes for kidney cancer

For every 100 cases of kidney cancer, around 80 individuals will survive for at least one year and around 65 will survive for more than five years.

The success of your treatment will depend on the type, stage and grade of kidney cancer you have. Every case is different and your doctor will discuss the likelihood of successful treatment in your specific case based on your biopsy results and how you respond to treatment.

After you have completed your treatment, you will continue to receive follow-up care from your kidney team, often from a urology specialist nurse. This will include follow-up blood tests, ultrasound scans and CT scans, initially every six months. The longer you remain free of cancer, the further apart your follow-up appointments will become. 

If you remain free of cancer, you will eventually be discharged into the care of your GP with advice to be alert for any symptoms of a relapse, such as blood in your urine, pain around your ribs or groin area, a lump in your back and unexplained weight loss. 

Reducing your risk of kidney cancer

While you can’t change your genetics, you can make lifestyle changes to reduce your risk of kidney cancer. This includes quitting smoking, losing any excess weight and managing your health to keep your blood pressure under control, and if you have diabetes, to keep your blood sugar levels under control.