Most kidney cancers cause no symptoms and are found by chance on an ultrasound or CT scan done for another problem; in one study, 6 in 10 patients were diagnosed this way [2]. When symptoms do appear, the most common are blood in the urine and flank pain that does not go away; a lump in the abdomen, unexplained loss of appetite and weight, tiredness and anaemia are also seen [1, 2]. Always show a doctor visible blood in your urine, even if there is no pain [4].
Key points
- Today most kidney cancers are found by chance; these tumours are usually smaller and at an earlier stage [2].
- The three classic textbook signs (blood in the urine, flank pain and a lump in the abdomen) are very rarely seen together; in one study fewer than 1 in 100 patients had all three [2].
- When kidney cancer causes symptoms, it is often larger or more advanced; almost half of the patients who came with blood in their urine had advanced disease [2].
- Smoking, obesity and high blood pressure are the most important risk factors that can be changed [6].
Symptoms of kidney cancer
| Symptom | Explanation | What to do |
|---|---|---|
| Blood in the urine (pink, red or rust-coloured urine) | The strongest sign of kidney cancer in people who see their GP [3]; but most people with blood in their urine do not have kidney cancer [5] | See a doctor even if it happened only once and there is no pain [4] |
| Flank pain that does not go away | Pain on one side of the back or in the side [1] | If it lasts several weeks, have it checked |
| A lump in the abdomen or side | Less common [1, 2] | See a doctor as soon as possible |
| Loss of appetite and unexplained weight loss | General symptoms [1, 2] | If you are losing weight without trying, see a doctor |
| Tiredness, heavy sweating or fever | General symptoms, seen more often in more advanced disease [2] | If unexplained and persistent, have them checked |
| Anaemia | Found on a blood test [1, 3] | The cause of unexplained anaemia needs to be found |
This table does not replace an examination by a doctor; in most people these symptoms have another cause.
When should I call my doctor?
Flank pain has many causes, such as a strained muscle or a kidney stone. But show these to a doctor as soon as possible:
- visible blood in the urine, even once and even without pain; especially if you are 45 or older [4]
- blood in the urine that did not clear after treatment for a urinary tract infection or came back [4]
- flank pain that does not go away, or a lump in the abdomen or side [1]
- unexplained weight loss or anaemia with no known cause [1]
A lot of blood or clots in the urine, being unable to pass urine, or severe flank pain with fever and shivering needs urgent care at an emergency department.
Who is at higher risk?
The main risk factors for kidney cancer [1, 6]:
- smoking
- obesity
- high blood pressure
- chronic kidney disease and advanced kidney failure [6]
- long-term overuse of certain painkillers, including over-the-counter ones [1]
- a family history of kidney cancer and inherited conditions such as von Hippel-Lindau disease [1]
Smoking, obesity and high blood pressure are the three main preventable causes; stopping smoking, losing excess weight and controlling blood pressure are the best things you can do to lower your risk [6]. There is still no proven screening test for kidney cancer in people without symptoms [2]. If several people in your family have had kidney cancer, or you have an inherited kidney condition, tell your doctor; in these people even a small amount of blood in the urine is investigated with kidney imaging [7].
If the doctor suspects kidney cancer, which tests are needed?
- 1
Urine and blood tests
A urine test shows blood and infection, and a blood test shows kidney function and anaemia [1].
- 2
Kidney ultrasound
A simple test without radiation that shows a mass in the kidney [1].
- 3
CT scan or MRI with contrast
Shows the size and position of the mass and its relation to nearby tissues, and whether the disease is confined to the kidney or has spread elsewhere [1]. To investigate blood in the urine, a CT scan of the urinary tract (CT urography) and a look inside the bladder with a camera (cystoscopy) may also be needed [7].
- 4
Frequently asked questions
A lump was found in my kidney by chance on an ultrasound; does that mean I have cancer?
Not necessarily. Some masses that look like cancer turn out to be benign [2]. A CT scan or MRI with contrast usually makes the type of mass clearer [1]. If it is cancer, tumours found by chance are usually smaller and at an earlier stage [2]. Read more: Small kidney masses and regular monitoring and What is the difference between a benign and a malignant tumour?
I saw blood in my urine but I have no pain; should I worry?
It needs to be checked. Visible blood in the urine, with or without pain, is the strongest sign of kidney cancer [3] and can also be a sign of bladder cancer [5]. But most of these people do not have cancer: in a study of more than 3500 people checked for blood in the urine, 9 in 10 had no urinary tract cancer, and kidney cancer was found in only 1 in 100 [5]. Read more: What are the symptoms of bladder cancer?
Does kidney pain mean kidney cancer?
Usually not. Flank pain has more common causes, such as kidney stones, infection or muscle and spine problems. Kidney cancer is usually painless, and by the time it causes symptoms the tumour has often grown larger [2]. Pain that does not go away, especially with blood in the urine or weight loss, should be checked [1].
Can a blood or urine test find kidney cancer?
If I stop smoking, will my risk of kidney cancer go down?
Smoking is one of the three main preventable causes of kidney cancer; stopping smoking, losing excess weight and controlling blood pressure are the best things you can do to lower your risk [6].
Can kidney cancer be cured if it is found early?
Yes, usually. In one study, almost none of the patients with stage 1 disease died of kidney cancer in the first 3 years; but with disease that had spread, about half of the patients died within that time [2]. For small masses, usually only part of the kidney is removed, and for some masses up to 3 cm destroying the tumour with heat (ablation) is also possible [8]. Read more: Kidney cancer
Referral criteria and diagnostic points (for doctors)
For physicians
NICE NG12 (updated 2026). Refer people aged 45 and over using a suspected cancer pathway referral for renal cancer (diagnosis or exclusion of cancer within 28 days) if they have unexplained visible haematuria without urinary tract infection, or visible haematuria that persists or recurs after successful treatment of urinary tract infection (recommendation 1.6.6) [4].
Presentation (prospective multicentre UK cohort, 608 patients with RCC). 60% were diagnosed incidentally (87% of stage Ia and 36% of stage III or IV). Visible haematuria was reported in 23%, and 49% of these patients had stage III or IV disease. The classic triad (mass, haematuria, pain) was present in only 4 patients (0.6%). Among patients with local symptoms: haematuria 68%, pain 62% and abdominal mass 7%; among those with systemic symptoms: fatigue 62%, weight loss 52%, sweats 38%, loss of appetite 38% and fever 10%. Symptomatic presentation was associated with poorer outcomes, and symptom patterns in benign renal masses were similar to those in RCC [2].
Primary care (GPRD case-control study, 3149 cases aged 40 and over). Visible haematuria was the strongest predictor (OR 37), followed by abdominal pain (2.8), microcytosis (2.6), raised inflammatory markers (2.4), thrombocytosis (2.2) and low haemoglobin (1.9). The PPV of visible haematuria in those aged 60 and over was 1.0%; together with the risk of bladder cancer, this warrants referral [3]. In DETECT I (3556 patients referred with haematuria), renal parenchymal cancer was found in 1.0% [5].
Microhaematuria (AUA/SUFU 2025). Definition: 3 or more red blood cells per high-power field on a single, properly collected specimen; a positive dipstick alone is not enough. High risk: cystoscopy and axial upper tract imaging (preferably multiphasic CT urography); intermediate risk: cystoscopy and renal ultrasound. With a family history of RCC or a genetic renal tumour syndrome, upper tract imaging regardless of risk group. Antiplatelet or anticoagulant therapy does not change the evaluation [7].
Localised renal mass (AUA 2021). Priority for partial nephrectomy in cT1a, selective use of thermal ablation for tumours of 3 cm or smaller, and an evolving role for renal mass biopsy [8].
Related cancer types
Related questions
References
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Numbers in the text, such as [1], refer to these sources. Sources with a “Study card” button are summarised in the site’s evidence library.
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