So there has long been a casual argument that cancer is a disease of civilization. That is, that cancer was rare up until at least the development of large cities and perhaps industrialization. This might suggest pollution of some sort is a vital precursor to cancer.

Robin Hanson posts on some evidence to back up this claim

In modern populations, tumours arising in bone primarily affect the young, so a similar pattern would be expected in ancient populations. … Another explanation for the rarity of tumours in ancient remains is that tumours might not be well preserved; however, experimental studies show that mummification preserves the features of malignancy. ..

We propose that the minimal diagnostic evidence for cancer in ancient remains indicates the rarity of the disease in antiquity.

Though if this is the case then it seems we may be dealing with a ubiquitous set of pollutants as wild animal deaths from cancer seem to be on par with human rates.