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Certain Tumor Characteristics Found on CT Help Determine Possibility of Lung Cancer

Patients and nodule characteristics can help determine the probability of cancer among lung nodules found on screening computed tomography (CT). These results were recently published in the New England Journal of Medicine.

Among patients who are at a high risk of developing lung cancer, many guidelines now include screening with low-dose CT. However, a major issue with this screening is the detection of nodules of the lung that are not cancerous. If these nodules are detected, patients undergo further testing, typically including an invasive biopsy, in which cells or tissue from the nodule are removed for laboratory examination to determine if they are cancerous or benign.

Biopsies are associated with pain, risk of infection, anxiety, potential for complications and cost. Therefore, researchers are trying to identify ways in which to reduce the number of biopsies of these nodules, while maintaining optimal detection of early lung cancer.

Researchers recently reviewed data from participants in the Pan-Canadian Early Detection of Lung Cancer Study (PanCan) and those in the British Columbia Cancer Agency (BCCA), in which participants at a high risk of developing lung cancer underwent screening with low-dose CT.

The researchers tried to determine if certain variables of the nodules and/or patients were more strongly associated with nodules being cancerous versus benign. The data included 1,871 participants in the PanCan study with 7,008 nodules and 1,090 participants in the BCCA study with 5,021 nodules.

Among participants with nodules found on CT screening, 5.5% in the PanCan study had lung cancer and 3.7% in the BCCA study had lung cancer.
Predictors of cancer included the following: older age of the patient, female gender, family history of lung cancer, a diagnosis of emphysema, a larger nodule size, a location of the nodule being in the upper lobe, part-solid nodule, and spiculation (spike-like shape).
The researchers concluded that “Predictive tools based on patient and nodule characteristics can be used to accurately estimate the probability that lung nodules detected on baseline screening low-dose CT scans are malignant .” Further validation of the accuracy in using these variables to help predict the possibility of cancer is necessary to take this information into mainstream clinical use. If validated, the hope is that the majority of unnecessary biopsies of lung nodules may be averted with maintaining optimal accuracy in detecting early lung cancer.

Reference: McWilliams A, Tammemagi M, Mayo J, et al. Probability of cancer in pulmonary nodules detected on first screening CT. New England Journal of Medicine. 2013:369;910-919.