Beating the big C

Source: The Weekend Australian
July 09, 2005

EVEN mention of the word "cancer" creates fear in some, but the long-held belief that a cancer diagnosis is a death sentence should be waning.

And, perhaps more importantly, the view that people always catch cancer by accident is also being challenged.

Cancer is the leading cause of death in Australia, with almost 38,000 deaths from malignant cancer each year.

But survival rates are improving steadily each year and there are measures people can take to lower the risk of developing many types of the disease.

According to the Cancer Council Australia, at least one in three cancer cases are preventable, and the number of cancer deaths could be almost halved by the implementation of effective cancer prevention programs. More than 15,500 cancer deaths each year are due to smoking, sun exposure, poor diet, alcohol, inadequate exercise or being overweight, the council says. AIHW statistics suggest that of the 90,000 new cases of malignant cancer per year, 12.5 per cent are attributed to smoking and 3.2 per cent to excessive alcohol consumption.

The Cancer Council Australia's Nutrition and Physical Activity Committee spokesman, Steve Pratt, is even more positive: he believes at least half of all cancers could be prevented with a healthy lifestyle.

"Over the long term, there's potential for 44,000 less cases of cancer and 18,000 lives saved every year," Pratt says. "Stop smoking, be physically active every day, aim for a healthy body weight, choose a varied diet with plenty of fruit and vegetables, be sun smart, avoid alcohol, and monitor your body for any changes."

Pratt says in recent years science has lost some of the links between specific foods and cancer prevention, and studies are more often disproving the links. "We just can't say any more that broccoli will prevent x cancer. But we know that generally speaking a good diet helps.

"It is unlikely there will be a silver bullet, but more an interaction and combination of a whole lot of things - but genetics and bad luck have a role to play too."

There is evidence that not eating enough fruit and vegetables probably increases the risk of oesophagal, lung, stomach and bowel cancer, and may also increase the risk of mouth, pharynx, larynx, kidney, ovary and bladder cancer. Eating processed meats and large amounts of red meat increases the risk of bowel cancer and eating large amounts of salt and/or salty foods probably increases the risk of bowel cancer, he says.

Currently there is no evidence of a link between fat intake and cancer, but eating high fat foods contributes to weight gain and being overweight or obese is a risk factor for several cancers, he says.

The Cancer Council Australia recommends a diet consistent with the Australian Guide to Healthy Eating - eat plenty of vegetables, legumes (pulses such as kidney beans, lentils and chickpeas) and fruit; eat plenty of cereals (including breads, rice, pasta and noodles), preferably wholegrain; choose foods low in fat and salt; and eat meat in moderation.

There is also evidence that regular physical activity reduces the risk of breast and bowel cancer and research also suggests regular physical activity may reduce the risk of endometrial, kidney, oesophagus and prostate cancers.

Prostate cancer:

Almost one man in ten will develop prostate cancer at some time in his life and it is the second largest cause of male cancer deaths behind lung cancer. There are 10,000 men diagnosed with the condition every year and 2600 die of the disease annually.

"We still don't have a good handle on what causes prostate cancer, but it is fair to say it seems to be a western society thing rather than an eastern society thing - so the types of food we eat may be a key determinant," says Phillip Stricker, the chairman of the department of urology at Sydney's St Vincent's Hospital. "Too much saturated fats, excessive calories, and not enough soy protein could be problematic."

Phyto-estrogens in soy protein seem to be a preventative and there are products containing extracts of phyto-estrogens on the market, associate professor Stricker says.

"It is very hard to prove or disprove their worth at this stage because we have to have a person taking the substance for 20 years before we can say it is a preventative.

"People who get very little sunlight appear to be at higher risk, so vitamin D may have a role to play in prevention and people deficient in the mineral selenium also appear to have an increased incidence of prostate cancer.

"It appears obesity increases your chances of developing the cancer - that may explain why Japanese do not get it. But Italians don't either, which has led to research suggesting tomatoes cooked in oil can be a beneficial preventative."

Breast cancer:

Over 11,000 Australian women are diagnosed with breast cancer each year and if all women lived to the age of 75, one in 11 would develop breast cancer by then. It can occur at any age, but the average age of women when they are diagnosed is 64. One third of those diagnosed are under 50.

The fight against breast cancer focuses on early detection via screening and self-examination, as the most important risk factors associated with the cancer are things none of us can do anything about: growing older and family history, says Helen Zorbas clinical director of the National Breast Cancer Centre.

There are a number of factors associated with increased risk, but they are related to lifestyle rather than diet, Zorbas says. But women with a heavier body weight are at greater risk, especially after menopause. And women taller than 174cm are also at greater risk than those who are shorter.

Reproductive factors also come into play: women who don't have children or who delay having children until after 30 are at greater risk. The more children the lower the risk, and breastfeeding modestly reduces the risk.

Skin cancer:

More than 380,000 Australians are treated every year for skin cancer. It is the most expensive burden on the health system of any cancer. Australia has the highest rate of skin cancer in the world, but the prevention of skin cancer is simple and well publicised: sun protection.

Skin cancer is caused by overexposure to ultraviolet (UV) radiation, says Craig Sinclair, chairman of the Cancer Council's skin cancer committee.

Protection is needed to prevent skin cancer even when UV levels are moderate. In some parts of Australia (for example, the tropical north) this is most of the day, all year round. In southern Australia, it is safe to go without sun protection in June and July, Sinclair says - unless you are in the Southern Alps, on the water, or out all day.

"When UV is forecast as moderate, wear a broad spectrum sunscreen with an SPF of 30-plus and use one teaspoon per limb," Sinclair says. "Create shady environments and check if the medication you are taking could increase your sensitivity to the sun."

Lung cancer:

Lung cancer has the largest number of deaths of any cancer because most cases are detected in the later stages. But the rates are decreasing and statisticians predict other cancers will take over its top deaths status in the coming decade, says Andrew Ellerman, chairman of the Cancer Council's tobacco issues committee.

Prevention is "obvious", Ellerman says. "Smoking is responsible for 80 per cent of all lung cancers.

"Atmospheric pollution, asbestos, radon, are relevant but insignificant in comparison to smoking, and there is no clear evidence to suggest any other factor will help prevent lung cancer." Smoking increases your risk of cancer in many other body parts. The list of smoking-related cancers includes: head (nose, nasal sinus, mouth, lip, tongue, throat, voice box); oesophagus (gullet); pancreas; kidney; bladder; stomach; liver; rectum; anus; cervix; vulva; penis; and blood (leukaemia). And quitting smoking has plenty of other health benefits. Smoking contributes to heart, respiration and circulatory disease; asthma; and low birth weight infants. Bowel cancer:

Bowel cancer is the second most common cause of cancer-related death in Australia. Almost 5000 people die from the cancer each year. According to the Cancer Council, around 25 per cent, or more than 3000 of the 13,000 bowel cancers diagnosed in Australia every year, could be prevented if people maintained a healthy body weight, ate a healthy diet and engaged in daily physical activity.

A National Health and Medical Research Council guide on bowel cancer says 66 to 75 per cent of bowel cancer cases could be prevented by eating a healthy diet and exercising regularly.

"Vegetables have been shown to provide strong protection against bowel cancer, therefore you should eat a wide variety, especially cruciferous vegetables such as bok choy, broccoli, brussels sprouts, cabbage, cauliflower, swedes and turnips," the NHMRC report says.

Eat plenty of fibre, especially wholegrain cereal fibres and wheat bran, and eat a low fat, low calorie diet. And cut back on red and processed meats.

High consumption of red and processed meats over a long period of time is associated with an increased risk of bowel cancer. It could also be beneficial to ensure you get the daily recommended dose of between 1000mg to 1200mg of calcium, as some studies have shown a link between calcium and bowel cancer prevention, while others have been unable to find a link.

Several studies have suggested that there is a link between a substantial intake of alcohol and bowel cancer. The US National Cancer Institute bowel cancer prevention website says among populations that consume a diet high in fat, protein, calories, alcohol, and meat (both red and white) and low in calcium and folate, colorectal cancer is more likely to develop than among populations that consume a low-fat, high-fibre diet. A diet low in vitamin D may also increase the risk of colorectal cancer.

And some studies have shown that the use of non-steroidal anti-inflammatory drugs may be associated with a reduced risk of colorectal cancer.

Cancer Council Australia: www.cancer.org.au