Prostate cancer is one of the most common cancers affecting men, especially elderly men in their sixties, seventies and eighties. It has been suggested that if every man lives long enough, he will eventually develop prostate cancer. In western countries, it is the cancer most frequently found in men after skin cancer. The disease is less common among Asian men, though rates in Asian populations are rising; something thought to be due to the increased levels of red meat and animal fat in Asian diets.
The prostate is a walnut shaped gland that wraps itself around the urinary outlet tube, the urethra, just under the bladder and in front of the rectum in human males. Females do not have this organ or any equivalent organ. The prostate produces a protein-rich fluid that nourishes and supports the sperm produced by the testicles. The sperm and prostatic fluid together form the semen ejaculated by males during orgasm.
As men age, the prostate enlarges, a condition known as benign prostatic hypertrophy, and symptoms caused by pressure on the bladder and the urethra develop. These include more frequent urination, a difficulty starting urination, pain on urinating and difficulty passing urine. In some cases, when the prostate enlarges the cells undergo a cancerous change. In many men, this happens so slowly they never know they have cancer. Some cases have been diagnosed as an "incidental finding" during the post-mortems done on men who have died from other causes. But in others, the cancerous change can be rapid and the prostate cancer can spread beyond the prostate into other organs, usually the bones of the pelvis and spine, before the man has symptoms. There is new evidence that a particular tumour gene, known as P53 indicates whether the man has a tumour likely to spread rapidly or grow slowly. If P53 is present in the tumour, it is usually a much more aggressive and dangerous cancer.