There is a twisted belief held by some in industrialized societies that cancer rates are growing primarily because people are living longer. It's a twisted belief because it treats cancer like a confirmation of success, instead of a warning to be heeded. The logic seems to go that, since people in industrialized societies no longer have to die at the age of 25 from bacterial infections, raiding homicidal tribes, or vicious beasts, they live longer, which is surely a victory for scientific progress, and cancer is just a side effect of our newfound longevity, one that will just as surely be understood and controlled in time, so that eventually humanity will be able to enjoy extreme longevity free of disease, essentially doing a better job than mindless nature ever could.
So goes the myth. Unfortunately, that fairy tale is on its last legs. For one thing, evidence suggests that foragers live far longer than civilization wants to admit, with the modal age of death for forager groups being seventy-two years. As study authors Gurven and Kaplan point out, this should not be surprising, since if the modal, or most common, age of death was consistently anything lower during the two million years of human forager existence, then humans would probably not have evolved the potential for a full seven decade lifespan in spite of regularly dying far before the majority of people ever got near that age. By contrast, chimpanzees that are kept do live longer than their wild counterparts--but only by about fifteen years, and at significant cost to their mental well-being. The reason why chimpanzees don't, say, live an extra forty years in captivity is because their lifespan is more or less predetermined by their evolution in the wild. Nature does not secretly inscribe the potential to live an extra four decades banking on the off chance that a chimpanzee might wind up in a zoo display. The lifespan is calibrated to the expectation of each chimpanzee living in its environment of evolutionary adaptation. Likewise, humans can naturally age to seventy-plus years not because technology and science have suddenly enabled them to, but because seventy-plus years was what humans regularly saw in the wild, hence an evolved life-cycle that anticipates a potential seven decade run, with negligible senescence between puberty and one's forties (see above link to Gurven and Kaplan study). Otherwise, as much as civilization wants to believe it, there is no way that is consistent with current understandings of evolution that technology could double or triple the natural lifespan of an animal simply by removing it from the wild for a few generations.
The second issue with the longevity myth of cancer is that there is virtually no evidence that cancer was common before civilization, and especially before industrial society, despite lifespans that would otherwise suggest the potential to develop age-related malignancies. For example, some preserved corpses from pre-contact South America and ancient Egypt exhibit signs of arteriosclerosis and arthritis associated with aging, yet, out of a sample of nearly a thousand mummies, only five instances of tumors, mostly benign, were found.
However, the most glaring problem with the longevity myth of cancer is the ongoing increase in rates of childhood cancers, which, according to the American Cancer Society, is the second leading cause of death in US children between five and fourteen. It's not even necessary to compare this with pre-industrial societies--we already know that childhood cancers were far rarer in the past and that the rate of incidence has been increasing by about 0.6% a year in the US since 1975. Across the industrialized world, these rates, along with adult cancer rates, are generally expected to continue trending upwards.
Civilization's tendency to normalize suffering and disease is truly disturbing. Cancer, once an unknown illness, is now considered a natural expression of aging, and, perversely, evidence of the necessity of technological medicine for a life free from suffering. The truth is, cancer is a toll that domestication exacts on the body. Similarly, the breakdown of social cohesion and cooperative community is a toll that domestication exacts on human interaction. The assumption of civilization is that humans by nature are inherently self-interested and, if left unchecked, will inevitably tear down society in an orgy of rancor and greed that can only be stopped by the imposition of a higher authority and that harmony can only be achieved by offsetting one individual's self-interest by leveraging another's. Such are the delusional legacies of Thomas Hobbes and Adam Smith. But just as physical diseases like cancer are being demonstrated to be the product of domestication, so are civilized assumptions of a repugnant human nature. Are qualities such as greed, vanity, jealousy, egocentrism, violence, and bellicosity inherent in humans? They are, insofar as the potential for cancer is also inherent in a latent sense. The potential to develop cancer has always been present in humans, as well as the potential for individualistic self-interest and the whole gamut of negative human qualities. Placing humans in a domesticated lifestyle, like the chickens in a factory farm, guarantees the manifestation of such unnatural and undesirable side effects. But even though cancer was always biologically possible, it is only recently, with the advent of domestication, civilization, technology, and the concomitant host of radical alterations to our environment, that cancer actually manifests--obviously a warning sign. Is it really such a stretch of the imagination, then, to consider that these same radical environmental changes to virtually all aspects of human life would also have a significant, and odious, influence on human character as well, eliciting the most loathsome social diseases along with the physical, mental, and spiritual ones?
There are many passages from the Dao De Jing that, two thousand years ago, had already apprehended the tendency of technology and progress to draw out the worst in people who otherwise would enjoy peace and harmony. Chapter 3 delineates this notion:
By not exalting the talented you will cause the people to cease from rivalry and contention.
By not prizing goods hard to get, you will cause the people to cease from robbing and stealing.
By not displaying what is desirable, you will cause the people's hearts to remain undisturbed.
and even more succinctly in Chapter 12:
The five colors blind the eye.
The five tones deafen the ear.
The five flavors cloy the palate.
Racing and hunting madden the mind.
Rare goods tempt men to do wrong.
Therefore, the Sage takes care of the belly, not the eye.
He prefers what is within to what is without.
This theme is again repeated in Chapters 19 and 20:
Drop wisdom, abandon cleverness,
And the people will be benefited a hundredfold.
Drop humanity, abandon justice,
And the people will return to their natural affections.
Drop shrewdness, abandon sharpness,
And robbers and thieves will cease to be [...]
See the Simple and embrace the Primal,
Diminish the self and curb the desires! [...]
Have done with learning,
And you will have no more vexation.
However, the final words of Chapter 46 are by far the most striking, leaving us with a profound message to contemplate:
There is no calamity like not knowing what is enough.
There is no evil like covetousness.
Only he who knows what is enough will always have enough.
(all excerpts translated by John C.H. Wu)