Computed tomography (CT) screening identifies many cases of early, curable lung cancer, according to the International Early Lung Cancer Action Program Investigators.

The size of the tumor on CT is also useful in predicting if the cancer has spread, or “metastasized,” to other body sites, the researchers report in the Archives of Internal Medicine.

Dr. Claudia I. Henschke, from Weill Cornell Medical Center in New York, and members of her group obtained results for nearly 29,000 people who underwent CT screening between 1993 and 2004.

A total of 464 cases of lung cancer were screen diagnosed, included 436 “non-small cell” lung cancers and 28 cases of “small cell” lung cancer. Non-small cell cancers, if caught early, are usually treated with surgery, whereas small cell cancers are typically treated with chemotherapy.

Among non-small cell cancers, the proportion of cases with no metastases ranged from 91 percent of patients in whom the tumor was 15 millimeters or smaller in diameter, to 55 percent of those with tumors 36 millimeters or greater.

All of the small cell cancers appeared as solid nodules. For these cancers, the proportion of cases with no metastases was 67 percent for tumors 25 millimeters or smaller versus 23 percent for larger tumors.

“The pattern confirmed herein suggests the usefulness of finding latent cancers at small sizes,” the authors point out. “Most lung cancers without evidence of lymph node metastases are curable, with the curability rate being higher at smaller sizes.”

SOURCE: Archives of Internal Medicine, February 13, 2006.