By Michelle Roberts
Digital health editor
Sir Chris Hoy, six-time Olympic cycling champion, has revealed he has advanced prostate cancer. The 48-year-old says the cancer has spread to his bones and is terminal.
Tributes have poured in and charities say raising awareness of the disease could help save other lives.
Prostate cancers can behave very differently. While some can spread quickly, others are very slow growing and may need minimal or even no treatment.
What is prostate cancer?
The prostate is a gland that is about the size of a walnut which sits just below the bladder within the pelvis.
It surrounds the urethra - the tube that takes urine out of the body through the penis.
Prostate cancer - abnormal and uncontrolled cell growth - often develops slowly.
There may be no signs or symptoms for years and some people never develop any problems from it.
But in others, the cancer can be aggressive and deadly.
Prostate cancer that's detected early has the best chance for successful treatment.
How common is prostate cancer?
One in six men will get prostate cancer at some point in their lives, says Cancer Research UK.
It is most common in older age - among men over 75. Cases in the under-50s are rare.
Men whose father or brother were affected by prostate cancer are at slightly increased risk.
It is also more common in black men.
Prostate Cancer UK has a 30-second online risk checker, external. Speak to your GP if you think you are at higher risk of prostate cancer.
Around 52,300 men are diagnosed with prostate cancer each year.
What symptoms should people check for?
needing to urinate more frequently - particularly at night
difficulty starting to urinate, weak flow and it taking a long time
blood in urine or semen
These symptoms can be caused by other conditions too - but it is important to have any changes checked by a doctor.
Is there a test for prostate cancer?
There is no single, diagnostic test.
Doctors make a diagnosis based on various measures.
This can include a prostate-specific antigen (PSA) blood test and a scan, as well as a biopsy, which involves taking a small tissue sample to examine in the laboratory.
PSA tests are not routinely used to screen healthy men for prostate cancer because the results can be unreliable.
A high PSA does not always mean cancer. It can go up if there is an infection, for example.
And some men with a raised PSA may have a prostate cancer that would not have caused problems or needed treatment, causing unnecessary worry and further investigations.
Researchers have repeatedly looked at whether it would be beneficial to introduce the screening. Those studies, overall, show that offering all men of a certain age a PSA test would only lead to a small reduction in the number of men dying from prostate cancer.
Men over 50 can usually ask their GP for a PSA blood test if they want to. Your GP will explain the potential benefits and risks of having a PSA test.
Doctors are looking at whether adding in MRI scans to PSA tests might improve the situation.
What about treatment?
Different options are available and your doctor will be able to advise which might be most suitable.
If the cancer is at an early stage and not causing symptoms or growing quickly, it might be possible to keep it under observation or "watch and wait".
Some prostate cancers can be cured with treatments such as surgery and radiotherapy.
Hormone therapy may also slow cancer growth.
It may also be possible to destroy the cancer cells using extreme cold (cryotherapy) or high-intensity focused ultrasound.
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