What role does fate play when it comes to the 145,000 people diagnosed with cancer each year in Australia and 125,000 people in Vietnam?

Smoking, sun exposure, poor diet, alcohol consumption and inadequate exercise are proven risk factors for many types of cancer, but new research shows this message is not getting through to many patients.

According to an international study led by the University of Newcastle and Vietnam Cancer Institute, and involving the University of South Australia (UniSA), Australian cancer patients identified "bad luck" or fate as the third most common perceived cause of their cancer—behind age and family history.

The study compared the perceptions between 585 cancer patients in Australia and Vietnam, analyzing differences across 25 possible beliefs about what may have caused their cancer.

Almost half of the Australian cancer patients believed “getting older” was the main cause of their cancer, while most Vietnamese patients cited “poor diet” as the main contributing factor of their cancer.

Overall, smoking was ranked the 5th most likely cause and alcohol the 9th most likely cause. This is despite repeated health messages that many cancers are preventable, and alcohol and smoking are both high risk factors for many cancer types.

UniSA Research Chair of Cancer Epidemiology and Population Health, Professor David Roder, says there are many misconceptions about what causes cancer.

“Unfortunately, people’s understanding of many cancer-related risk factors is modest to low. People’s beliefs about what may have caused their cancer are complex and likely to be impacted by multiple factors, including cultural beliefs,” he says.

The survey revealed some significant differences between Australian and Vietnamese cancer patients, including:

• “Getting older” was listed as the main cause of cancer by the Australian patients; the Vietnamese cancer patients ranked it a lot lower, in 10th place;
• “Poor diet” was the top perceived cause of cancer among the Vietnamese patients, while Australian patients ranked diet in 11th place;
• “Air pollution” was listed as the second main cause of cancer by Vietnamese participants, whereas Australian patients listed it in 10th place;
• Australians ranked “alcohol” as the 12th contributing factor to causing cancer and “lack of exercise” as the 17th. Vietnamese listed “alcohol” in 7th place and “lack of exercise” in 12th place.

The two cultures gave similar rankings in just four areas: smoking (5th overall), mental illness (20), prescribed medication (23) and injury or physical trauma (25).

HMRI researcher Dr Alix Hall, one of the study leaders, says a substantial proportion of both Australian (27%) and Vietnamese (47%) patients held fatalistic views about the possible causes of their cancer.

“In the Australian sample, “bad luck” was ranked third and in the Vietnamese sample it was ranked fifth.

“This is concerning because it suggests they believe they have little control over their health. That may affect their willingness to change their behavior when it comes to diet and lifestyle, and influence their decisions relating to treatment and/or care,” Hall says.

The researchers say the study findings underline why public health campaigns need to highlight accurate information about the possible causes of cancer.