Lung Cancer Detection with LDCT Linked to Lower Brain Metastasis Risk

Add a lower risk of brain metastasis to the ever-growing list of benefits associated with low-dose CT (LDCT) lung cancer screening.

According to a study published June 3 in the Journal of Thoracic Oncology, patients who have their lung cancer detected with LDCT have half the risk of a subsequent brain metastasis than do patients whose disease is diagnosed via alternative methods.

“In this study, we showed that the mode of primary [lung cancer] detection is significantly associated with the risk of [brain metastasis] development after [lung cancer] diagnosis, where the [brain metastasis] risk is half-fold lower among patients whose primary [lung cancer] was detected through LDCT screening versus chest X-ray screening, incidental detection, or clinical symptoms-based detection,” said the team led by Summer S. Han, Ph.D., assistant professor in the medicine and neurosurgery department at Stanford University School of Medicine.

Among lung cancer patients, brain metastasis is common. Roughly 10 percent of patients present with it at the time of diagnosis, and roughly 40 percent go on to develop it during the course of their disease. Early detection of a brain metastasis is critically important, the team said, because existing evidence shows patient survival significantly increases if these metastases are either asymptomatic or well controlled.

Han’s team set out to discover whether the modality of diagnosis impacted the risk of brain metastasis. For their study, they pulled 1,502 participants between ages 55 and 74 from the National Lung Screening Trial who were diagnosed with primary lung cancer between 2002 and 2009. Of the group, which included no patients with brain metastasis at time-of-diagnosis, 41.4 percent had their disease detected with LDCT, and 58.6 percent were diagnosed with chest X-ray or incidental detection.

According to their analysis, 143 patients (9.5 percent) developed brain metastasis after their lung cancer diagnosis. The team determined that patients diagnosed via LDCT experienced a much lower three-year incidence of brain metastasis than did other patients – 6.5 percent and 11.9 percent, respectively. This reduction in risk persisted among subgroups of patients with early-stage primary lung cancer.

There was as a link between brain metastasis and lung nodule development, the team said, although it did not rise to the level of statistical significance. Using a subgroup of 362 patients, they discovered that nodules in the 12 patients who did develop brain metastasis grew faster than did the nodules in the 350 patients without brain metastasis – specifically, 6.4 mm versus 3.6 mm per month.

It is possible, they said, that the lower risk of brain metastasis could be because tumors detected via LDCT have a different biology.

“The reduction in brain metastasis risk may be due to a potentially different tumor biology of the tumors detected by LDCT screening that are less aggressive and slow growing, which needs to be confirmed by further investigation,” they said.

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