Prostate Cancer

 What we know
 Incidence
 Costs
 Environmental risk factors

What we know

Prostate cancer is cancer of the small walnut-shaped sex gland in men that occurs when cells in that part of the body begin to grow out of control. The prostate, located underneath the bladder, produces seminal fluid that nourishes and transports sperm. Prostate cancers are very common and small areas of cancer may stay dormant for many years.

Incidence

Prostate Cancer incidence is lowest in Asian countries and highest in Scandinavia. Around 306,369 cases are diagnosed each year in Europe. The lowest European rates are in Southern and Eastern Europe, while the highest rates are found in countries in Scandinavia and northern Europe [1].

Figure 1 Age standardised (European) incidence and mortality rates, prostate cancer, males [2] Enlarge the picture

Costs

Although there appears to be no estimates of the economic burden of prostate cancer in Europe, UK estimates from suggest that in 1997 the disease cost the health service at least £45 million per annum, whilst in Sweden, the incremental healthcare cost per patient with prostate cancer corresponded to 33000 SEK during the first year. [3], [4]

Little is known about the causes of prostate cancer. More established risk factors include:

 Age - The majority of men with prostate cancer are aged over 60 years and the disease is very rare in men under 50.
 Family History - Men with a brother or father who developed prostate cancer at a young age have an increased risk. Men with a family history of breast cancer also have an increased risk.
 Ethnic group - Prostate cancer is more common in men of African descent.

Environmental risk factors

Only 5-10% of prostate cancer cases can be attributed to inherited factors, suggesting a greater role for environment agents. These include high fat consumption, identified as a risk factor in a number of epidemiological studies, red meat consumption and low green vegetable consumption as well as exposure to radioactive substances.

Other environmental agents implicated are cadmium, the largest sources of which are cigarette smoke and food, and pesticides.

More recently, however, analysis of the environmental risk factors for prostate cancer has shifted to the potential role of the fetal environment. The developing organism is particularly susceptible to the effects of hormonally active substances. Chemicals of particular concern include endocrine disrupting chemicals (EDC), which have the potential to mimic or interfere with the delicately balanced hormone signalling pathways the lead to the development of the prostate.

The prostate develops under the control of the androgen hormones, responsible for the development and maintenance of the male sexual characteristics, and estrogen, responsible for female sexual development and reproduction. It is postulated that fetal exposure to environmental estrogens or anti-androgens at critical periods of development, perturb the normal hormone levels affecting prostate growth. Bisphenol A (BPA) for example, a chemical that mimics estrogen and found in many plastics used in many food and drink packaging applications, has been shown to cause prostate enlargement in animal studies [5].

It is interesting to note that the incidence of prostate cancer highly correlates with breast cancer incidence, suggesting that the two cancers may have causal factors in common. Both breast and prostate tissue are responsive to hormones, in particular estrogens, androgens and progesterone. For more information on breast cancer please see our breast cancer webpage.

To curb the increasing incidence in prostate cancer prevention efforts will be critical. Prostate cancer is a disease that primarily affects older individuals. As a result of the changing European demographic, with its aging population a sharp increase in the incidence of prostate cancer is predicted. Further research into the identification of the causes of the disease is thus needed, as are precautionary measures to help people avoid potential risk factors.

 For more information please see the Collaborative on Health and Environment Cancer Working Group.