The current situation and causes of prostate cancer

There are obvious geographical and racial differences in the incidence of prostate cancer, with the highest incidence in Australia/New Zealand, the Caribbean and Scandinavia, and lower incidence in Asia and North Africa. Worldwide, the incidence of prostate cancer ranks second among all male malignant tumors. In the United States, the incidence of prostate cancer has surpassed lung cancer and has become the number one tumor that endangers men's health. According to the American Cancer Society, there will be approximately 217,730 new cases of prostate cancer in the United States in 2010, and 32,050 will die from the disease.

In Europe, there are about 2.6 million new cases of prostate cancer diagnosed each year, accounting for 11% of all male cancers and 9% of all male cancer deaths. The incidence of prostate cancer in Asia is much lower than that in Europe and the United States, but it has been on the rise in recent years. In 1993, the incidence of prostate cancer in China was 1.71 per 100,000 people, and the mortality rate was 1.2 per 100,000 people; in 1997, the incidence rose to 2.0 per 100,000 people, and by 2002 it was 3.4 per 100,000 male population.

Another set of data from the National Cancer Prevention and Research Office/National Cancer Registry Center collected from 30 registries across the country showed that the incidence of prostate cancer was 1.96/100,000 population from 1988 to 1992, 3.09/100,000 population from 1993 to 1997, and 4.36/100,000 population from 1998 to 2002. In 1979, there were only 98 new cases of prostate cancer in Taiwan, China; in 1995, it had risen to 884, with an age-standardized incidence rate of 7.2/100,000 population. In 2000, there were 635 deaths, with a mortality rate of 5.59/100,000 population.

In 2007, the Shanghai Center for Disease Control and Prevention reported that the incidence rate of prostate cancer in men was 11.81/100,000, ranking fifth among male malignant tumors.

Prostate cancer patients are mainly elderly men, with a median age of 72 for newly diagnosed patients and a peak age of 75-79. In the United States, more than 70% of prostate cancer patients are over 65 years old. It is rare in men under 50 years old, but the incidence and mortality rates increase exponentially after the age of 50. The probability of developing prostate cancer in individuals under 39 years old is 0.005%, which increases to 2.2% (1/45) in the 40-59 age group and 13.7% (1/7) in the 60-79 age group.

The risk factors for prostate cancer are not fully understood, but some of them are recognized. One of the most important factors is heredity. If a first-degree relative (brother or father) has prostate cancer, the risk of developing prostate cancer will increase by more than 1 times. If 2 or more first-degree relatives have prostate cancer, the relative risk will increase to 5 to 11 times. Patients with a positive family history of prostate cancer are diagnosed about 6 to 7 years earlier than those without a family history.

A subgroup of the prostate cancer population (about 9%) has true hereditary prostate cancer, which means that three or more relatives have the disease or at least two of them develop the disease at an early stage (before the age of 55). Currently, many studies on gene polymorphisms and genetic susceptibility to prostate cancer are underway, which will provide genetic evidence to explain the occurrence of prostate cancer.

Exogenous factors can influence the progression from latent prostate cancer to clinical prostate cancer. The identification of these factors is still under discussion, but a diet high in animal fat is an important risk factor. Other possible risk factors include lack of exercise, low intake of lignans and isoflavones, and excessive intake of cured meat products. Sunlight exposure is negatively correlated with the incidence of prostate cancer. Sunlight can increase vitamin D levels and may therefore be a protective factor for prostate cancer. In Asia, where prostate cancer is less prevalent, the consumption of green tea is relatively high, and green tea may be a preventive factor for prostate cancer.

Genetics are an important risk factor for the development of clinical prostate cancer, and exogenous factors may have an important influence on this risk. The key issue is that there is not enough evidence to prove that lifestyle changes (reducing animal fat intake and increasing the intake of fruits, grains, vegetables, and green tea) will reduce the risk. There are some studies to support these claims, and this information can be provided to the family members of men with prostate cancer who ask about the impact of diet.