Here is a thought provoking article that suggests that cancer rates were far lower in antiquity. The study points to low rate of incidence in Egyptian Mummies (less than 1 in 100) as compared to modern prevalence (one in 8 deaths).
One worthwhile point the article linked above references is that cancer was around before humans and therefore cannot be said to be fully the consequence of man-made environmental changes.
However, that study doesn’t preclude the idea that cancer is a often or almost always a result of environmental effects on cell reproduction.
Together, the two points raise the distinction of the existence of cancer versus the prevalence of cancer. Take the following questions:
1) Does cancer exist in non-human primates?
2) How common is cancer in non-human primates?
If cancer in non-human primates is far lower than in humans, it’s worth asking why. Additional clarifications can be made:
3) Do cancer rates increase for non-human primates in captivity versus a natural habitat?
4) Is the full explanation about cancer rate disparity to be located in age?
5) How much of the disparity in cancer rates between primates has to do with the presence of negative environmental factors?
Fascinating fact: humans, dogs and lions are the only known species to get cancer of the prostate.
When the environment is so radically changed by pollutants that you get drastic spikes in cancer.
Our environment changes our bodies. Sometimes drastically, in the form of cancer.
The vast majority of cancer occurs in people over 50.
However, some cancers disproportionately target people in younger age brackets. Hodkins Lymphoma, for example, especially affects people in their 20s and 30s. Brain and nervous system cancers seem to be more evenly proportional across all age brackets. Leukemias, while affecting every age bracket, are especially prone to affect young children from 0-4 years old.
Cancer, which includes a whole host of diseases that involve out of control cell replication, is definitely enhanced by age. Why this is true is not completely clear.
In many cases, such as lung or liver cancers, the accumulation of time often correlates with the accumulation of environmental toxins, which can increase the disruption of normal cell activity and lead to malfunctioning cells that replicate out of control. Cancers that target the young are less clearly related to environmental toxins, though that hypothesis (that environmental factors contribute to cancer in younger humans) cannot be ruled out completely.