davenn said:
a lot of the "increased prevalence" comes with the increased and better screening techniques
Yes, though hopefully the OP is aware that the ancients didn't
have cancer screening techniques, so that should be an obvious difficulty in figuring how often they got cancer. I don't think it is possible to really know and at best we would have to assume demographically corrected rates are the same. Demographics alone tell us whereas somewhere around 1 out of 2 get cancer today, for the ancients it was more like 1 in 20(detected or not) - just because they only lived half as long.
that's definitely some of the problem but doesn't cover all specific cancers ... skin, breast and bowel for example
As the article says ... life styles and natural exposure play a part that is totally unrelated to genetic breakdown assoc. with old age.
I meant to word that a bit more generally; it is not just internal mistakes, but externally caused genetic damage also accumulates.
Environment ... more, unprotected sun-tanning (ozone depletion related) carcinogenic chemicals in the air, water etc
that our ancestors were not subject to, even if your went back only a few 100 years ( I suspect they were more likely to dies from various plagues than cancer )
Man is producing carcinogenic chemicals over the last 100 years that were never even heard of 100++ years ago
While that is obviously true, I would caution against falling victim to the "naturalistic fallacy"(natural = better) that probably is either the cause or effect (or both) of the thinking in the OP.
Difficulty normalizing screening accuracy aside, the link I posted included a graph showing the drop in lung cancer rates (in the UK) recently due to the drop in smoking rates. So clearly, human-caused carcinogens matter. But the ancients smoked too. How much, I don't know. The second leading cause of lung cancer, at least in the USA, is radon. Presumably an ancient who lived in a tent wouldn't be subject to it, but an ancient who lived in a cave might have had worse exposure.
Other factors that may have increased cancer rates in ancients:
--Increased sun exposure
--Poorer hygeine
--Poorer sanitation
--Poorer food quality and preservation
Though admittedly, I'm not sure how much of those last three were cancer causing and how much they just made people sick in other ways. But a quick google tells me that salt meat preservation (common before refrigeration), for example, may cause cancer.
[edit]
Man is producing carcinogenic chemicals over the last 100 years that were never even heard of 100++ years ago
http://www.unc.edu/courses/2005spring/envr/132/001/Carcinogenesis.pdf
Interesting link. Page 3 shows charts of
death rates (age adjusted), and I'm going to assume that prior to about 1950 we had essentially no treatment options for cancer (other than perhaps removing tumors), so the substantial drops in death rates for uterine and scomach cancers are likely due primarily due to other advances in medicine and standard of living. E.G., I'm speculating that it is the invention/proliferation of refrigeration that caused stomach cancers to drop by 2/3 from 1930 to 1960 (half for men, 80% for women).
