from "Rust Out" by Dr. Royce Bailey, page 31

Change in bowel or bladder habits.
A sore that does not heal.
Unusual bleeding or discharge.
Thickening or a lump anywhere on the body (especially under the arm or breast).
Indigestion or difficulty swallowing.
Obvious change in a wart or mole.
Nagging cough or hoarseness.

In 1950 cancer killed about 1 in 40 people. 
After the year 2001 cancer will kill 1 in 4 of us.

-American Cancer Society Guidelines