The second factor is smoking. Smoking causes one-third of cancer, and that accounts for the major increase in cancer. If you correct for age and correct for smoking, cancer rates are coming down. There's no evidence that's really convincing. It's almost all hype.
Synthetic chemicals are just a drop in the bucket compared to natural chemicals.
You make a thousand different chemicals when you roast your coffee. Every plant is full of natural pesticides it uses to kill insects. When you add it all up, 99.99 percent of pesticides that go into you are natural, and .01 percent are synthetic residues. The amounts of synthetic chemicals we ingest are just trivial compared to the amounts of natural chemicals we ingest. It isn't that natural chemicals are harmless and synthetics are bad.