CHICAGO (CBS) — If you are overweight, you might be at risk for specific cancer cases, but as the American Cancer Society announced Wednesday, the more common cancer groups are on the decline.

Willie James Ramsey was diagnosed five years ago with lung cancer. On Wednesday at the University of Chicago Medical Center, he was a patient proud to call himself a cancer survivor.

“I just felt like if I didn’t give up, then God wouldn’t give up on me,” Ramsey said.

Lung cancer is one of several cancers on the decline, according to a new report by the American Cancer Society.

At the same time, Dr. Otis Brawley said, “We’re seeing a rise in cancers of the thyroid, cancers of the esophagus, cancer of the liver, cancer of the pancreas and cancer of the throat.”

It translates to more than 1.6 million new cases of cancer overall. More than 500,000 people will die of cancer in the U.S. this year alone.

Doctors say obesity, lack of exercise and high caloric intake is behind many of the new cases.

“It’s clear that there’s an increased risk of getting cancer among people who are overweight,” said Dr. Richard L. Schilsky, of the University of Chicago.

As for the drop in cancer rates for other forms of cancer, Schilsky said, “I think we should all be encouraged. I think there’s still a lot of work to do. I think people need to take personal responsibility for their health. … People need to follow a healthy lifestyle.”

Researchers and doctors credit the drop in cancer cases to patients being better educated about keeping themselves healthy.

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