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.

Genetic etiology of cancers

Earlier this month- about a week ago- in my other blog <docSamBlog>  I published a post citing ( using the argumentative scientific approach )  that oncologist might wish to use the argumentative  approach that with the data suggestion that 20% of tutors are genetically determined and that for the other 80% which have an environmental cause , and further that because there is a lag period of requiring up to 20 years or more before the precancerous lesion becomes an established cancer, and further it could be argued that in the first quarter of life  ( 1-24 Yeatrs these predetermined factors have not had sufficient time for these precancerous lesions to become established, that  a higher if not indeed most of the cancers of this age period  may ineed be of genetic origin

Today I read a report (or was it on the TV) detailed the history of this tumor by a neurological surgeon from my alma mater. Apparently after a vigorous chemotherapy protocol the lesion resolved only to appear in another part of the brain which I believed again went into remission . I would like to comment that what we are seeing is the epigenetic effect of chemotherapeutic effect on cancer genes.. Also that the approach for treating the majority- probably 80% or more-whose etiology aare caused by environmental factors- like smoking, food (nutrition), radiation etc. Epigenesis may explain the often observed phenomena of miracle cured in children.-