Cancer is not a rare disease. Depending on your lifestyle, age, sex, genetics and many other factors, you can be likely to get cancer in your lifetime. But aren’t we overestimating the risk of this disease? Scientists from University of Sydney and Bond University say that estimates provided by Australian Institute of Health and Welfare can be a bit high.
It is important to have accurate estimates for cancer risk and death, but current ones are probably exaggerated. Image credit: Sgerbic via Wikimedia (CC BY-SA 3.0)
Australian Institute of Health and Welfare (AIHW), like many similar organizations around the world, is estimating lifetime risks of cancer diagnosis and mortality. For example, in 2013 they said that the risk of breast cancer is 12.7 %, prostate cancer – 18.7 %, colorectal cancer – 9 % for men and 6.4 % for women, lung cancer – 7.6 % for men and 4.5 % for women. If you think about it, those are huge numbers and they can be truly frightening. If you know 10 women, it is very likely that at least one of them is going to get breast cancer and, possibly, die from it. But is this true?
Just like any other organizations, AIHW use age specific cancer incidence and mortality data in a calendar year to estimate lifetime risks of cancer diagnosis and mortality. And scientists do not mean to criticise them for it. However, at the same time there are thousands of other competing causes of death, to which this statistics do not account for and that’s not good. This leads to gross overestimations, especially for men. Scientists decided to account for these other factors and see how those lifetime risks of cancer diagnosis and mortality estimates would change.
The risk of breast cancer was reduced from 12.7 % to 12.1, prostate cancer – from 18.7 % to 16.2, colorectal cancer – from 9 % to 7 for men and from 6.4 % to 5.5 for women and so on. Pretty much the risk of any kind of cancer is highly overestimated, especially for men, who often die because of heart disease or other causes. Again, scientists are not trying to criticise, they are just saying that the methodology could be improved to increase the accuracy of these risk estimates.
Authors commented that “Australian agencies should consider adopting methods for adjusting for competing mortality when estimating lifetime risks, as currently employed in North America and the United Kingdom, to increase the accuracy of their estimates”.
This is a mixture of good and bad news. On one hand, it is good to know that the lifetime cancer risk is actually lower than predicted all over the internet. However, on the other hand, this means that these estimates were produced using unreliable methods, which is not great. Better methods are needed in order to know the risk exactly and search for ways to reduce it.
Source: University of Sydney