Cancer etiology: genetic or environmental

In order to prevent what is going to kill you, you need to know what those factors are. Let’s zero in on Canada’s number one killer: cancer.

Taking Canadian vital statistics on causes of death for the year 2011, there were 246,596 deaths. Statistics Canada divided the population into 4 age groups: 1-24, 25-44, 45-64, 65 years and over. The percentage of cancer deaths were 10%, 21%, 44% and 28% respectively.

Not surprisingly, cancer was the number one cause of death in all 4 age groups. But what surprised me was that cancer caused 10% of the 2,679 deaths in the youngest age group.

Most oncologists estimate that only 10-20% of cancers are genetically determined, with the rest due to environmental factors, with diet responsible for 35% and tobacco 25%(at least for males with the percentage in females rapidly approaching the same figure). It is also well-documented that the main reason for the higher cancer deaths in those 45 and over for lung cancer, and possibly also for the other environmental factors like diet and radiation, is due to the so-called lag period.

If this hypothesis for the mechanism of environmental carcinogenesis applies, then genetically-determined cancers in the 1-24 age group should be responsible for more cancer deaths with fewer from environmental such as by food, smoking, radiation, etc. Such information may give the oncologists, epidemiologists, and genetic counselling specialists new tools for their management of this major killer.

Author: Semeon Hrushovetz

Retired Physician, Researcher, Lifelong Learner. Promoting healthy aging and life extension. Visit or check my previous sites: blog: website:

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