Why is the incidence of Cancer increasing?

I read the first chapter of Parks, book of Preventive and Social Medicine for the first time today,
That led me to Ponder over this :

Man was plagued by diseases (Pun intended) created by the piling of garbage, rapid industrialization and poor city planning, during the 17-19th centuries.
These diseases had micro organismic causes and soon the Germ Theory of Diseases was propounded by Robert Koch and Louis Pasteur.
The invention of microscopes soon led to the discoveries of pathogenic micro organisms in quite succession in 1940s to 1970s.

Soon, Man succeeded in developing chemotherapeutic agents that could kill these agents. Cheaper and widespread availability of drugs led to its drastic use and subsequent fall in acute infectious diseases was noted.

Man, at this point, had mingled with the mother Nature. He tried to alleviate fellow humans and increase standard of living by prolonging the expectancy of life.

The next generation which followed, had the luxuries of lesser infectious diseases but, Nature had another challenge in store for us.

Chronic non infectious, lifestyle or genetic diseases became more common. Drugs for cancer have become the Holy Grail for modern Medicine.

Some day when mankind achieves victory over these chronic diseases, age related debilitations will prove to be the limiting factor to the immortality of mankind and then we will have to search for anti aging drugs and elixirs of life.

"Nothing is immortal in the material world" will finally dawn to the homo sapiens sapiens and that's when, man WI learn to lead a simple but meaningful life.