Disease of the month: Prostate cancer

With no screening programme, this killer disease claims 10,000 lives a year – Fergus Bescoby takes us through the implications

Good news for the male population: British scientists have moved a step closer to developing a urine test to identify men at risk of getting prostate cancer.

They have discovered that a protein found in urine is affected by a genetic change linked to the cancer. Although more work is still needed, this could potentially lead to the development of a reliable test costing as little as £5.50.

This development could offer a welcome alternative or replacement to the prostate-specific antigen (PSA) blood test, which is notoriously inaccurate and costly. Figures show that 10-15% of men will have high enough PSA levels to warrant carrying out a prostate biopsy, but only 2-3% will actually require treatment.

There is currently no routine screening programme in the UK, although men with a family history of the disease can have a PSA blood test to detect the early warning signs.

Even with this testing, prostate cancer remains the most common cancer in males in the UK, killing about 10,000 men in Britain every year, a figure which has almost tripled over the last 30 years.

What is the prostate?

The prostate gland is found only in men. It lies just beneath the bladder, in front of the rectum and is normally about the size of a chestnut. The urethra (the tube which passes urine from the bladder) runs through the middle of the prostate. Its main function is to make fluid, which protects and enriches sperm.

The prostate often gets gradually bigger after the age of about 50 (benign prostatic hypertrophy). By the age of 70, about eight in ten men have an enlarged prostate. It is common for older men to have urinary symptoms caused by a benign (non-cancerous) enlargement of the prostate.

Prostate cancer symptoms

Often prostate cancer doesn’t have any symptoms, but when they do occur they may include:

• Urinating frequently
• Difficult or painful urination or ejaculation
• Delay or hesitancy before urinating
• A feeling that the bladder has not ­completely emptied
• Blood in urine or semen
• Disturbed sleep because of the need to urinate

In advanced prostate cancer, the following may occur:

• Weight loss
• Bone pain
• Pain in the loins, pelvis or lower back

It is vital to know that there are a number of non-cancerous medical conditions that may also cause these symptoms, such as infection or benign prostate enlargement.

What causes Prostate cancer?

The causes of prostate cancer are not yet fully understood. Cases are rare in men aged under 50, but there are certain factors that place some men at higher risk of developing the disease than others:

• Being overweight or obese
• Being of African-Caribbean or African-American descent and living in western countries
• Men with one or more first-degree relatives (father, brother, or son) diagnosed with prostate cancer have an increased risk of prostate cancer, especially if the relative was diagnosed before the age of six
• There is some suggestion that a fat-rich diet may contribute to prostate cancer, but this is not proven

Diagnosing prostate cancer

There are several methods to check for the presence of prostate cancer. The simplest is the digital rectal examination, in which a gloved finger is inserted into the rectum, through which an enlarged prostate can be felt. Blood tests are the next step, although as previously mentioned, a urine test will hopefully soon be available which will replace the less accurate PSA test. More sophisticated tests include the use of ultrasound scans and X-rays, but the following are some of the common methods:

• Digital rectal examination (DRE): A doctor inserts a lubricated, gloved finger into the rectum and feels the prostate. A DRE can sometimes detect an enlarged prostate, lumps or nodules of prostate cancer, or tenderness from prostatitis
  
• Prostate-specific antigen (PSA): The prostate makes a protein called PSA, which can be measured by a blood test. If the PSA is high, prostate cancer is more likely, but an enlarged prostate can also cause a high PSA
  
• Prostate ultrasound (transrectal ultrasound): An ultrasound probe is inserted into the rectum, bringing it close to the prostate. Ultrasound is often done with a biopsy to test for prostate cancer
  
• Prostate biopsy: A needle is inserted into the prostate to take tissue out to check for prostate cancer. This is usually done through the rectum