Results from the phase 2 MERIDIAN trial show that circulating tumor DNA (ctDNA) can help detect and guide treatment of residual disease in patients with locally advanced head and neck squamous cell carcinoma.
Researchers used the RaDaR assay, a personalized blood test, to monitor patients after treatment. The test showed very high accuracy, with positive results strongly predicting cancer recurrence. In many cases, ctDNA detected relapse months before it appeared on scans, giving doctors an early warning window.
Patients with detectable ctDNA after treatment had a much higher risk of recurrence. In one case, a patient treated early with the immunotherapy rilvegostomig cleared their ctDNA and remained disease-free for nearly two years.
The study suggests that treating patients based on ctDNA results—before tumors are visible—could help prevent relapse. Ongoing updates to the trial aim to improve detection and expand early treatment, with the goal of increasing cure rates in this high-risk cancer.