Study highlights CT findings that could mask lung cancer, leading to delayed diagnosis
New research highlights several CT findings that could prevent radiologists from spotting lung cancer in patients with interstitial lung disease (ILD)
Patients with ILD may be especially vulnerable to delays in lung cancer diagnosis. New data published in European Radiology indicates that lung cancer in these individuals could go undetected for more than three years for a significant number of patients, putting them at risk of disease progression that would require more extensive treatment. Experts sought to understand what factors contribute to these delays, leading them to identify several tumor and radiologic characteristics common to later diagnoses.
For their work, the group retrospectively assessed the cases of 54 patients with both ILD and lung cancer. Four thoracic radiologists reviewed patients’ imaging to determine the earliest callable date—when the majority would have raised concern about a nodule—to the time when providers first expressed clinical concerns. The timelines were then compared alongside a handful of tumor factors, including size, morphology, staging, growth rate (volume doubling time), and treatment regimens, radiologic findings and survival outcomes.
The team’s efforts revealed that 50% of the cohort had a delayed diagnosis, with the mean delay time exceeding 3 years. The group found that tumors subject to delayed diagnosis grew significantly slower (mean volume doubling time: 1.42 vs. 0.22 years).
In terms of radiologic factors, researchers determined that fibrosis, ground glass opacity or bronchovascular bundles (63%), misinterpretation as infection or exacerbation (15%), minimal interval growth (11%), and invisibility on CT (15%) all contributed to delayed diagnoses as well. Tumor size, morphology, stage and histologic subtype were similar between the groups, as were survival rates.
“Half of the lung cancer cases in ILD patients were diagnosed with significant delay, primarily due to parenchymal masking and subtle imaging findings, rather than biologically aggressive disease,” Jae Ho Sohn, MD, with the Department of Radiology and Biomedical Imaging, University of California, San Francisco, and colleagues explained. “Clinicians should stay alert for malignancy in peripheral fibrotic regions with slow-growing nodules.”
The group added that although there does not appear to be a clear survival impact, future research should examine the timelines of how delays can impact tumor growth, treatment and outcomes.
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In addition to her background in journalism, Hannah also has patient-facing experience in clinical settings, having spent more than 12 years working as a registered rad tech. She began covering the medical imaging industry for Innovate Healthcare in 2021.