Dr. David Gerber, a medical oncologist at the University of Texas Southwestern Medical Center in Dallas, said incidence rates have decreased for most types of cancer, including the four most common -- lung, colorectal, breast, and prostate --but some cancers are increasing.
The National Cancer Institute said breast cancer incidence decreased from 1999 to 2004, but has held steady in the last eight years.
"However, diagnosed cases actually increased for several cancers, including pancreas, kidney and adenocarcinoma of the esophagus, all of which generally are associated with excess weight," Gerber said in a statement.
In addition, Gerber, a medical oncologist, said he was treating an unprecedented number of lung cancers in patients who have never smoked.
"Cancer in never-smokers now represents about 15 percent of lung cancer cases, and when you figure that there are more than 200,000 cases a year of lung cancer diagnosed in the United States, that's more than 30,000 cases of never-smoker lung cancer," Gerber said. "Part of the reason -- and this is actually good news -- is that healthcare providers are diagnosing more of it due to improvements in scanning practices and the use of new technologies."