Why do americans have a near 50% chance of developing cancer?

Longevity. About 20-30% deaths in the us are due to cancer. It is not that cancer is more prevalent in the us than other countries. The incidence of cancer increases with increasing age. Cancer is the result of cumulative damage to the dna and the longer a person lives, the more damage is incurred. Life span in the us is longer than in less developed countries.