What is prostate cancer?

A cancer occurs when a clone of cells develops and reproduces (mitosis) – no longer under the homeostatic (regulatory) control of the body. The living cells (epithelial cells) of the prostate ducts are liable to cancerous change – at first the abnormal cells remaining within the ducts (pre-cancer, preinvasive neoplasia PIN) but later invading through the duct walls to invade the gland (invasive cancer). Often the cancer is indolent and has such a low mitotic rate that enlargement of the cancer may occur over some years. Sometimes the growth may be much faster. A biopsy of the gland is performed to make the diagnosis of prostate cancer. Under the microscope the glandular cells that have transformed into a cancer produce an adenocarcinoma and the microscopist may predict the potential aggression of the individual cancer by various microscopic features – the Gleason Grading Score.

Later, when the cancer breaches the capsule of the gland, then the cancer cells have more free access to blood vessels and lymphatics and the opportunity to spread (metastasise) occurs.

Uncommon in younger men, the frequency with which cancer affects the prostate gland increases with age. In fact a small spot of prostate cancer is very common in older men, occurring in up to 80% of 80-year olds who, having died from a cause other than prostate cancer, have had their prostate examined at post-mortem. These little spots of prostate cancer – or foci, as they are called – occur in 70% of 70-year olds, 60% of 60-year olds and 50% of 50-year olds. The relationship between these spots of cancer and the development of a malignant growth is as yet unknown.

PIN – prostatic intraepithelial neoplasia

A microscopic view of the prostate in low and high

A microscopic view of the prostate in low and high

An even more benign variant is termed prostatic intraepithelial neoplasia, or PIN. There is controversy whether PIN is significant or not. Some doctors regard PIN as being the equivalent of the female conditions in breast and cervical cancer which lead to the development of an invasive tumour. However, the great majority of doctors have no such view and remain unconvinced as to whether or not PIN has any relationship with overt prostate cancer.

PIN may cause no symptoms and may be completely benign, and this is in contrast to the ‘equivalents’ in the breast and cervix. If you are diagnosed as having PIN, you should be reassured that hopefully there will be no progression to an invasive cancer.

You will also be advised to keep an annual check on the situation by PSA testing and continued medical follow-up.

Undifferentiated tumour. Minimal glandular differentiation. Diffusely infiltrating anaplastic cells

Undifferentiated tumour. Minimal glandular differentiation. Diffusely infiltrating anaplastic cells

Prostate cancer may cause problems with urination. These can be due either to the physical enlargement of the gland or to the invasion of the prostatic urethral valves so that they become rigid and are unable to open and shut under normal control. This will cause significant symptoms, making it very difficult to pass urine normally. The bladder enlarges, and may do so to such an extent that in the end it becomes impossible to pass urine. This can cause considerable pain and requires admission to hospital for catheterisation to relieve the obstruction. Symptoms are relieved within a few moments of passing the catheter.

Advances in treatment mean that a diagnosis of prostate cancer need no longer trigger our worst fears. Indeed, for many men, prostate cancer is a relatively indolent disease – a cancer that causes no significant problems in their lives. A significant number of others are cured of their illness, whilst a further proportion may have their symptoms eased for a significant period of time. In any event, survival is a probability not a remote possibility.