THE FIRST STEP toward curing cancer is detecting it. The earlier a cancer is found, the better the chances are that it can be controlled or cured completely. A cancer that is found early has not had time to damage nearby tissues or spread to distant ones. Finding tumors early is easier or more important in some kinds of cancer than others, but early detection is helpful in treating all kinds of cancer.

Warning signs and checkups

The cheapest and easiest way to detect possible cancer is to notice changes that occur in one's own body. The American Cancer Society lists seven cancer warning signs that people should watch for:

• Change in bowel or bladder habits
• A sore that does not heal
• Unusual bleeding or discharge (flow of liquid)
• Thickening or lump in the breast or elsewhere
• Indigestion...