CT evaluates latent cancers in large lung cancer screening trial

Smaller solid lung cancers in asymptomatic patients are less likely than larger ones to have metastasized, with implications for a better prognosis, according to new research from the International Early Lung Cancer Action Program.

Tumor size in relation to disease stage is an important prognostic indicator in lung cancer cases. The earlier tumors are found, with no metastases, the better the chances are for a cure.

Technical developments in CT technology have allowed researchers in the long-running I-ELCAP to apply submillimeter slicing across the chest in a single breath-hold as part of their lung cancer screening investigation. This advance has led to the discovery of smaller tumors.

Using the I-ELCAP data from nearly 29,000 patients in 38 institutions, researchers determined the number and types of cancers found, presence of metastases, and consistency of tumors (solid, nonsolid, or part-solid). Findings were published in the Feb. 13 issue of Archives of Internal Medicine.

Of the 464 cancers found in the total population studied, 436 were non-small cell carcinomas, which are less aggressive. On average, 85% of the non-small cell group had no metastases, but the researchers determined that cancer size was directly related to rate of metastases:

• of tumors 15 mm or smaller, 91% had no metastases

• 16 mm to 25 mm, 83% had no metastases

• 26 mm to 35 mm, 68% had no metastases

• 36 mm or larger, 55% had no metastases

The finding that tumors were more likely to have metastases as they grew larger was particularly true for solid lesions but less true for part-solid lesions. The association did not exist for nonsolid lesions.

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