Retrospective Study Results Demonstrate Lung Imaging Pattern Differences Among Cancer Types

Advanced non–small-cell lung cancer (NSCLC) harbors genetic mutations that have led to the development of targeted therapies directed toward these mutations and improving clinical outcomes. Among these mutations is the KRAS G12C mutation, which occurs in approximately 13% of NSCLC cases. This mutation has been found to be associated with a history of smoking and with white race. Research has found distinct radiological features associated with NSCLC mutations, and research is ongoing to determine if there are differences between the oncogenic drivers of NSCLC that may lead to differences in prognosis or metastatic potential.¹

In a recent Cancers journal article, Wu and associates evaluated the results of a retrospective analysis to determine the imaging features and metastatic patterns of NSCLC harboring the KRAS G12C mutation compared with NSCLC harboring other genetic mutations, including patients with fusion rearrangements (RET, ALK, ROS1) and EGFR mutations. Imaging reviews were performed at baseline, including computed tomography scans of the chest, abdomen, and pelvis with or without positron emission tomography, and computed tomography and/or magnetic resonance imaging of the brain. The primary tumor was identified (when possible), the lymph nodes evaluated, and other sites were examined for metastases, including the lungs, pleura, pericardium, visceral organs, liver, adrenal glands, bones, brain, and subcutaneous soft tissues.¹

There were 215 patients with KRAS-positive NSCLC identified during the review. All tumors in this patient group were adenocarcinomas, and there was a high incidence of extrathoracic metastases involving distant lymph nodes, the liver, adrenal glands, bone, and soft tissue. Of these patients, 83 patients had the G12C mutation, while 132 had non-G12C KRAS mutations. When the imagining patterns were compared, the G12C group was more likely than the non-G12C group to have lung cavitation (13% vs 5%) and lung metastasis (38% vs 21%). When the fusion rearrangement group (n = 215) was compared with the KRAS G12C group, the G12C group had a lower occurrence of pleural metastasis (21% vs 41%) and lymphangitic carcinomatosis (4% vs 39%), but had a higher occurrence of brain metastasis (42% vs 22%). When compared with patients with NSCLC harboring EGFR (n = 117), the G12C group had a higher frequency of distant nodal metastasis (10% vs 2%) and a lower lung metastasis frequency (38% vs 67%). The G12C group had a lower frequency of intrathoracic metastasis (52%) than the fusion rearrangement group (75%) and the EGFR group (82%), but a higher frequency of soft tissue metastasis (13%) than the fusion rearrangement group (4%) and the EGFR group (0%).¹

Differences in imaging patterns between NSCLC patients harboring the G12C mutation and other genetic mutations may provide direction in the future for clinicians diagnosing and treating patients with NSCLC.

Reference

1. Wu MY, Zhang EW, Strickland MR, et al. Clinical and imaging features of non-small cell lung cancer with G12C KRAS mutation. Cancers (Basel). 2021;13(14):3572. doi:10.3390/cancers13143572.