Controlling weight can help a person reduce the risk of cancer, said an oncologist from the NCI-designated Dan L Duncan Cancer Center at Baylor College of Medicine.

"There have been countless studies comparing cancer risk in obese and normal weight people," said Dr. Kent Osborne, director of the Duncan Cancer Center and the Lester and Sue Smith Breast Center, both at BCM. "We do not know exactly how and why obesity affects cancer risk, but we know there is an increase, so it is important for everyone to control their weight to minimize this risk."

Research has linked obesity to a greater risk of developing esophageal, pancreatic, colorectal, breast, endometrial, kidney, thyroid and gallbladder cancer, Osborne said.

In some cancers like breast cancer, there is also an increase in the risk of recurrence if a patient already has the cancer and is obese.

Many other factors, such as genetics, may play a role in cancer development, but keeping a normal weight is one thing people can change and it may help, he said.

Effect on breast cancer

BCM researchers are actively engaged in studying the relationship between cancer and obesity. Dr. Sao Jiralerspong, assistant professor in the Smith Breast Center, is specifically looking at the effect on breast cancer.

In December 2011, Jiralerspong presented new research that showed obesity may contribute to worse survival outcomes in early stage breast cancer patients.

He is now studying drugs like metformin that reduce the effects of obesity in the body to determine if it can reduce the risk of developing cancer.

"This study is one of many important examples that provide more evidence that weight control is an important factor in the fight against cancer," said Osborne.