PHILADELPHIA, Oct. 29 (UPI) -- U.S. researchers found no significant correlation between smoking and the stage of the disease or the aggressiveness of breast cancer tumors.

Dr. Matthew Abramowitz of the Fox Chase Cancer Center, in Philadelphia, and colleagues examined the medical records of 6,162 breast cancer patients at the time of initial diagnosis from 1970 to 2006 at Fox Chase Cancer Center and found 9 percent of the patients were current smokers.

"We hypothesized that tobacco use could result in more advanced stage or more aggressive breast cancer presentation but that doesn’t appear to be the case," Abramowitz said in a statement.

"There is no good news about smoking but since about 10 percent of our patients are smokers, this research provides us with some relief. The question that remains is will smoking affect their survival? In other words, does smoking affect the tumor’s behavior, its effect on the treatment to kill the cancer or recovery from treatment?"