ctDNA Testing Reduces Time to Treatment for Lung Cancer Patients

A nonrandomized clinical trial published in JAMA Network Open revealed that circulating tumor DNA (ctDNA) before tissue diagnosis can reduce the time to treatment in patients with suspected advanced lung cancer. The study’s results emphasize the utility of liquid biopsy as a complementary diagnostic tool in lung cancer.

According to the American Society of Clinical Oncology, roughly 238,340 adults in the United States will be diagnosed with lung cancer, with non-small cell lung cancer (NSCLC) comprising 81% of all lung cancer diagnoses. The five-year relative survival rate for NSCLC is only 28%, with higher survival rates in women than men.

As with any cancer treatment, early diagnosis and prompt treatment initiation are the best indicators for survival. Understanding the varying factors that may reduce the time to treatment can be critical for developing standards of care.

In this study, researchers recruited 150 patients suspected of having advanced NSCLC from the Princess Margaret Cancer Center University Health Network in Toronto, Ontario, Canada. Patients were enrolled from July 1, 2021, to November 30, 2022.

All the patients had evidence of advanced lung cancer using radiologic diagnostic tools before a tissue diagnosis. Each patient had a plasma ctDNA test with a next-generation sequencing (NSG) assay before having a biopsy. After ctDNA testing, participants had a diagnostic biopsy and tissue NGS.

Scientists referred to the cohort in this study as the Accelerating Lung Cancer Diagnosis Through Liquid Biopsy (ACCELERATE) cohort. They evaluated the time from referral to treatment initiation in patients with advanced nonsquamous NSCLC. They compared the ACCELERATE cohort to a reference cohort with standard tissue genotyping and tissue diagnosis.

Among the 150 participants in the study, 60%, or 90 participants, were diagnosed with advanced nonsquamous NSCLC. The time to treatment for patients in the ACCELERATE cohort ranged from 27 to 52 days, with a median time to treatment of 39 days. Comparatively, the reference cohort had a much longer time to treatment, with a median time to treatment of 62 days and a range of 44–82 days.

The researchers noted that the median time between sample collection to plasma genotyping results was seven days. Meanwhile, tissue genotyping results took roughly 23 days. Approximately 23% of patients with advanced nonsquamous NSCLC in the ACCELERATE cohort could begin lung cancer treatment before tissue sample data was available. Additionally, 12% of participants with advanced nonsquamous NSCLC changed their targeted therapy based on plasma results.

The researchers concluded, “This nonrandomized clinical trial found that the use of plasma ctDNA genotyping before tissue diagnosis among patients with suspected advanced NSCLC was associated with accelerated time to treatment compared with a reference cohort undergoing standard tissue testing.”

Many healthcare professionals maintain that liquid biopsy can be vital for disease diagnosis, especially in oncology. For example, some researchers use ctDNA testing to minimize the risk of colorectal cancer treatment. Beyond the rapid turnaround time of liquid biopsy compared to standard tissue biopsy, clinicians also emphasize that the ease of ctDNA testing can improve screening rates, early diagnosis, and early treatment. Continued research evaluating liquid biopsy's benefits, risks, and effectiveness across oncology — specifically lung cancer — may inform clinical diagnostic guidelines.