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Research into causes and prevention of prostate cancer

Men and women discussing prostate cancer

This page tells you about research into the causes and prevention of prostate cancer. There is information about

 

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Research into prevention and causes of prostate cancer

Researchers are looking into what causes prostate cancer, including research into diet, physical activity, sun exposure, and different types of job. Some researchers are trying to find gene changes that may cause prostate cancer. 

Trials are looking at whether some drugs may be able to prevent prostate cancer in the future.

Cancer Research UK supports a lot of this research. You can find out about prostate cancer trials on the Cancer Research UK Clinical Trials database.

 

CR PDF Icon You can view and print the quick guides for all the pages in the Treating prostate cancer section.

 

 

Researching prostate cancer causes and prevention

Researchers are looking into what causes prostate cancer, including research into diet, physical activity, sun exposure, and different types of job. Some researchers are trying to find gene changes that may cause prostate cancer. 

Trials are looking at whether some drugs may be able to prevent prostate cancer in the future.

Cancer Research UK supports a lot of this research. You can find out about prostate cancer trials on the Cancer Research UK Clinical Trials database.

 

Understanding the causes of prostate cancer

Researchers are always trying to find out more about what causes certain types of cancer. The UK Genetic Prostate Cancer Study is collecting blood and tissue samples from people with prostate cancer. These samples will be studied, along with information about how well people respond to treatment, to find out what they can tell us about the causes of prostate cancer.

The Prostate ICGC Project is also looking at changes in the genes of prostate cancer cells to learn more about the disease and how to treat it. The SEARCH study is looking at the genes of 32,000 people with various cancers, including prostate cancer.

The Birmingham Prostate Cancer Association Study (BiPAS) is looking at lifestyle and genetic factors that may increase the risk of prostate cancer. They hope to find out what effects diet, physical activity, sun exposure, and different types of job have on the risk of prostate cancer. The researchers also want to find out about particular genes that may increase the risk of developing prostate cancer. This study may also give more information about whether regularly testing the level of a protein called prostate specific antigen (PSA) is helpful in diagnosing prostate cancer. The study has closed and we are waiting for the results.

 

Diet and chemoprevention of prostate cancer

Research into preventing cancer using drugs or diet is called chemoprevention. In the past 10 years there has been a lot of interest in the prevention of prostate cancer. This is because prostate cancer is such a slow growing cancer and may be much easier to stop or slow down than many other types of faster growing cancers. Research into chemoprevention of prostate cancer includes

The EPIC study

Cancer Research UK is supporting the UK arm of a major piece of European research called EPIC. This is the largest ever study investigating possible links between diet and cancer. Half a million people are taking part and will keep a record of everything they eat and drink. The researchers will keep in touch with them for years to see who gets cancer and who doesn't. Then they will be able to see if any patterns emerge from the diets of people who get cancer. Prostate cancer is one of the cancers included in the EPIC study.

Fat in the diet

Countries that have a low fat and high vegetable intake in their diet have lower rates of prostate cancer. When men from a low risk country move to the USA (where prostate cancer rates are high), and start eating a western diet, their rates of prostate cancer increase dramatically. But it is not certain whether this is due to fat intake. Studies are ongoing throughout the world to find out the exact effect of fat, and the type of fat, on prostate cancer risk.

The EPIC study will look into the diets of men who go on to develop prostate cancer and may add to the knowledge of the role of fat in prostate cancer. A big advantage of the EPIC study is that the people taking part keep a detailed diary of what they have eaten. So the study is more accurate than other diet studies where people are asked to look back at what they regularly eat.

Lycopenes in tomatoes

Lycopenes are chemicals found in tomatoes that may help to prevent prostate cancer. Lycopenes are antioxidants and so may help to stop cell damage in the same way as the antioxidant vitamins. All forms of tomatoes, including ketchup, contain lycopenes although the body may absorb lycopenes better if the tomatoes are processed or cooked. Some studies looking into lycopenes and prostate cancer have shown a reduction in prostate cancer. 

Some doctors believe that the evidence about lycopene is promising enough to encourage men to increase the amount of tomatoes in their diet. The ProDiet study is trying to find out if it would be possible to increase the amount of lycopene and green tea in the diet in men who are at risk of prostate cancer. The study is also looking at whether the increase would show up in blood tests.

We don't know exactly how lycopenes work. Scientists throughout the world are trying to develop compounds that are similar to lycopenes, which might be used as dietary supplements in the future. 

Soy

Countries that have a high intake of soy in their diet tend to have much lower rates of prostate cancer (and other types of cancers) compared to countries where soy intake is fairly low. The protection against cancer may come from phyto oestrogens in soy. Phyto oestrogens are chemicals found in plant foods (phyto means plant). They are similar to the female sex hormone oestrogen. 

There are different types of phyto oestrogens. Some are found in soya bean products. Others are found in the fibre of whole grains, fruit, vegetables and flax seed. Milk may also contain phyto oestrogens, but this depends on what the cows have been eating.

Men who eat a diet high in phyto oestrogens may have a lower risk of prostate cancer. In some studies, eating phyto oestrogens regularly over several weeks reduced oestrogen levels. Scientists think the active ingredients in soya are isoflavonoids and are investigating these, particularly one called genistein. Isoflavonoids can mimic oestrogen and may delay the growth of prostate cancer. This plant oestrogen is weaker than the oestrogen produced by our bodies. We need more research results before we know how important soy is in preventing prostate cancer and other types of cancers.

Selenium and Vitamin E

Antioxidant vitamins and minerals may help to prevent cancer when included in a healthy, balanced diet. In theory, antioxidants help prevent body cells from being damaged by oxygen particles called free radicals. The damage can lead to the cells becoming cancerous.

Vitamin E and the mineral selenium are two antioxidants that some doctors thought might help prevent prostate cancer. An international trial called SELECT tried to see if this could be proved. This trial has now been closed, because early results showed that neither selenium nor vitamin E, taken alone or together, helped to prevent prostate cancer. A Canadian trial looked into whether selenium, vitamin E and soy together could prevent early changes in the prostate gland changing into an invasive cancer. They found it did not prevent it. 

Finasteride (Proscar)

Another chemopreventative agent is a hormone drug called finasteride. Finasteride is already used to treat benign prostatic hyperplasia (BPH) and has been tested in clinical trials to see if it can prevent prostate cancer. It is well known that prostate cancer responds to the hormone testosterone. Finasteride helps stop the hormone testosterone changing into its active form (dihydrotestosterone – DHT). So the levels of active DHT are lowered in the prostate.

One very large phase 3 clinical trial using finasteride in the USA recently published some results. This trial is called the Prostate Cancer Prevention Trial (PCPT). They found that finasteride did seem to be able to lower the risk of prostate cancer. But men taking it had side effects, including difficulty getting an erection and a lower sex drive. Although the overall incidence of prostate cancer was lower, the researchers found that quickly growing, high grade prostate cancer was more common in the finasteride group.

Dutasteride

Dutasteride is a similar drug to finasteride. It is also a treatment for benign prostate hyperplasia. In 2010 the results of a large international trial called REDUCE were published. The trial was for men at increased risk of developing prostate cancer. The results showed that dutasteride reduced the risk of developing prostate cancer by about 20% over the 4 years that the men were followed up. The side effects included a lower sex drive and difficulty getting an erection. 

Green tea

Asia has much lower rates of prostate cancer than other parts of the world. Some scientists believe that this may be due to the high intake of green tea throughout Asian countries. Laboratory studies have shown that extracts from green tea can stop cancer cells from growing. Some research has looked into the possible role of green tea in preventing cancer in people, but it mostly hasn't found any links. We need much stronger evidence to prove that green tea helps to prevent cancer in humans. 

The ProDiet study is trying to find out if it would be possible to increase the amount of lycopene and green tea in men's diets who are at risk of prostate cancer. And it also wants to whether the increase would show up in blood tests.

 

Genes and prostate cancer

Researchers are looking for genes that could increase the risk of cancer. Some genes have been identified that seem to increase prostate cancer risk.

Cancer Research UK scientists in London and Leeds discovered PTEN. This is an important gene involved in prostate cancer. This gene is being studied to find out how it works and how it affects prostate cancer. This work may lead to new treatments for prostate cancer in the future. 

Another gene, discovered in the USA, is called MSR1. This was found to run in some families who had a history of prostate cancer. It may be important in increasing the risk of developing prostate cancer. 

Researchers in the UK have also discovered a gene called E2F3 which appears to be overactive in high grade prostate cancer. This may help doctors to decide which men need treatment for prostate cancer and which men may only need active monitoring.

Families that carry the breast cancer genes BRCA1 and BRCA2 also have an increased risk of prostate cancer. The IMPACT trial in the UK is looking at screening men for prostate cancer who have an increased risk because of the BRCA1 or BRCA2 gene. 

The PROFILE study aims to find out more about family history and risk of prostate cancer. It hopes to possibly identify other faulty genes that might increase the risk of prostate cancer. 

In future it may be possible to carry out genetic tests for prostate cancer risk in the same way that it is becoming possible for breast cancer. Men with a higher than average risk may have tests more often, or from an earlier age. Or we may be able to develop a drug to prevent prostate cancer developing in this risk group.

The PROGENY study is looking in detail at the genes of prostate cancer cells. The researchers hope it may help them understand more about how prostate cancer develops, why some cancers spread and others don't and why some prostate cancers respond to treatment and others don't.

 

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Updated: 18 March 2014