The National Institute for Health and Care Excellence has just published its first guidelines on improving the diagnosis and management of kidney cancer. Nice has had a lot on its plate but the fact that it has taken nearly three decades to come up with this guidance says a lot about the disease: it has a much lower profile than it deserves and is probably the one common form of cancer that most people never consider.

It now accounts for one in 25 of all new cancer diagnoses in the UK, affecting about 14,000 people a year, and is on the increase with the number of new cases up around a quarter over the last decade. Most (63 per cent) of those affected are men, and in 2021 the then-opposition MP Wes Streeting was one of them. Now, of course, he is health secretary and, while I am not party to the discussions that go on in ivory towers, I am in no doubt that he has been a driving force behind the new guidance.

So how much do you know about your kidneys? Not a lot, according to a survey by the charity Kidney Research UK. While 9 out of 10 of the 2,000 people surveyed believed they had a good knowledge of how their kidneys worked, 8 out of 10 couldn’t correctly identify where theirs were, and a similar proportion appeared to have no idea that the organs filtered their blood. Hmm…

Most people have two kidneys (some are born with one, and very rarely you can have three) and they are tucked under the ribs at the top of both loins. They are bean-shaped and about the size of a clenched fist.

They receive about 1,800 litres of blood a day, filtering off about 180 litres, which is then largely reabsorbed and concentrated down to 1-2 litres of urine. As well as getting rid of excess fluid and waste products, the kidneys produce hormones and help regulate several vital functions, ranging from vitamin D and red blood cell production, to salt and blood pressure levels. Suffice to say that while you can live perfectly well with just one healthy kidney you can’t, as one in four people surveyed believed, survive without both.

Cancer is just one of many diseases that can affect the kidneys, and there is no clear cause in most people. Recognised risk factors include being overweight, male and/or having some types of existing kidney disease or stones. Age is another (a third of cases are in people over 75), as is having a close relative with the disease.

Smoking accounts for about 15 per cent of cases: carcinogens from tobacco smoke are excreted in urine where they can cause bladder cancers too (as can some other chemicals like solvents and dyes from occupational exposure). And there is evidence that long-term anti-inflammatory drugs such as ibuprofen and naproxen may increase the risk too, although this doesn’t seem to apply to aspirin.

I have listed some of the symptoms of kidney cancer below — some of which can be caused by other conditions — but I want to focus on the most common one that is relatively easy to spot and which should never be ignored: blood in your urine. Visible blood, even a rosé-type tinge, in the absence of an obvious cause such as a urinary tract infection, should always prompt further investigation.

Indeed, the Nice guidance states that visible blood in the urine in someone 45 or over, without an obvious cause, should prompt immediate referral to a specialist on the fast-track suspected cancer pathway. The same urgency applies even if it started with a urinary tract infection but persists once this has been treated. However, it is a red flag symptom at any age. Rarely, even children can get kidney cancer.

Not that you can always see the blood. Lots of people have invisible blood in their urine (microscopic haematuria) that may only be picked up by dipstick testing during investigation for another problem, or as part of a life insurance medical.

Dealing with this can be a challenge, not least because it’s not sinister in many cases as some people have “leaky” kidneys that allow red blood cells into their urine. However, it too shouldn’t be ignored, particularly in higher risk groups such as the over-45s and smokers (past or present).

Increasingly cancers are detected during scans for other problems — Streeting was being investigated for kidney stones — and this can present challenges too because at least one in ten of us has a cyst or other “shadow” on our kidneys, most of which are nothing to worry about.

However, some of these will require monitoring and biopsy and the new Nice guidance aims to improve this process so fewer cancers slip through the net. You can read the full guideline at nice.org.uk

The common symptoms

Blood in your urine is the most common symptom. Others include pain in the side (upper loin) and sometimes a noticeable lump. The rest are less specific but indicate a potentially serious underlying problem. They include unexplained weight loss, fatigue and breathlessness due to anaemia and recurrent fevers/night sweats.

Surgery is the main treatment for kidney cancer — and all that is generally required in earlier stage disease — either to destroy or remove part of the kidney, or completely remove the affected organ. Caught early, the cure rate is about 90 per cent. However, in advanced disease where it has spread to other parts of the body (often the bones) only 15 per cent of people will still be alive 5 years after diagnosis.