Prostate Cancer - What is it?
Prostate cancer is a disease that begins to affect men from around the age of 45 years. Although it is unusual in this younger age group, the incidence of prostate cancer increases dramatically with age. Prostate cancer develops as a result of faults in the genes that control growth in the prostate which leads to unregulated growth of the prostate cells (a cancer). These faults can either be inherited or developed. At present, we do not fully understand the process by which this occurs but there is increasing awareness of the risk factors associated with developing prostate cancer (see section on risk factors).
How common is prostate cancer?
Prostate cancer is the most common cancer in men in the UK. A quarter of all new cases of cancer diagnosed in men are prostate cancers. Each year, nearly 35,000 men are diagnosed and more than 10,000 die from the disease. Around 300,000 new cases of prostate cancer are diagnosed in Europe each year. The lowest rates are in Southern and Eastern Europe and the highest rates are in Scandinavia and Northern Europe. Worldwide, more than 670,000 men are diagnosed with prostate cancer each year. The highest rates are in the USA, Australia, New Zealand, Western and Northern Europe whilst the lowest rates are in East and South Central Asia.
The stages of prostate cancer
Prostate cancer can develop in any area within the prostate and spread within it. Early prostate cancer is mostly confined within its own fibrous capsule and if discovered at this stage, is called localized prostate cancer. If left to develop further, prostate cancer can grow to extend beyond the prostate capsule before it spreads throughout the body. If discovered at this stage, it is said to be locally advanced prostate cancer. Finally, it can spread to distant sites within the body in a process known as metastasis by entering the blood and lymph system. Often prostate cancer spreads to the bones and lymph glands within the body. It can also affect the liver, lung and brain. When discovered at this stage it is said to be advanced prostate cancer.
Symptoms and signs of prostate cancer
It is important to point out that there are usually no signs or symptoms in the early stages of prostate cancer. However, prostate cancer may present with following signs (which are also symptoms of non-cancer prostate disease such as benign prostatic hyperplasia (BPH).
- The need to pass urine more frequently, often during the night.
- The need to rush to the toilet.
- Difficulty in starting to pass urine (hesitancy).
- Straining or taking a long time while passing urine.
- A weak flow of urine.
- Feeling that your bladder has not emptied fully.
Sometimes men only realise something is wrong once the cancer starts to spread. These symptoms may include:
- Blood in the urine (haematuria).
- Bone and back pain.
- Pain when pass urine or ejaculating.
- Pain in the testicles.
- Weight loss
What are the risk factors for prostate cancer?
At present, the established risk factors for prostate cancer are age, family history and ethnicity.
Age is the strongest risk factor for prostate cancer. Men under 50 have low risk which increases significantly with age thereafter (see figure below).
A family history of prostate cancer is one of the strongest known risk factors for this disease. Approximately 5–10% of all prostate cancer cases and 30–40% of early-onset cases (men diagnosed <55 years) are inherited. The risk increases two to three times for men with a first-degree relative (father, brother) diagnosed with prostate cancer. The risk can be as high as seven times if 2 or more relatives have the disease.
Ethnicity has been shown to be important in prostate cancer. In the UK, black Caribbean and black African men have two to three times the risk of being diagnosed or dying from prostate cancer than white men, while Asian men generally have a lower risk.