Smoking intensity may predict lung-cancer mortality, according to new research from West Virginia University.

Researchers led by Nancy Guo at the Mary Babb Randolph Cancer Center found that lung-cancer patients who smoked two or more packs of cigarettes each day had a 58-percent higher risk of their lung cancer returning or spreading to other organs, compared to nonsmoking patients.

Smoking intensity and the stage of cancer when diagnosed are the only two predictive factors of lung-cancer mortality, the authors wrote.

Patients who smoked more than 61 packs a year had the greatest risk of recurring cancers, and their survival times were the most limited. These patients were also 41 percent more likely to die from lung cancer than patients who smoked less.

“Because five-year survival rates of patients with non-small cell lung cancer are only about 15 percent, it’s useful to know which patients are most likely to have their tumors come back,” Guo said. “Our study showed that those who smoked more than 61 packs a year are more likely to develop tumor recurrence and should be considered for more aggressive therapy.”

The study was published online March 20, 2009 in the journal Lung Cancer.