An ultrasensitive method for measuring circulating tumor DNA (ctDNA), a non-invasive biomarker for quantifying cancer burden in patients is reported online this week in Nature Medicine. This method is more useful than existing techniques, as it is cheaper, provides both high sensitivity and can be used one patients with various different tumor genotypes, for which recurrent mutation data is known.
Maximilian Diehn and colleagues used data from over 400 patients to develop a sequencing approach that covers recurrent gene mutations in lung cancer. With this method, they detected ctDNA with high specificity in all samples from another set of patients with stage II and advanced disease and half of the samples from stage I cancer patients. The amounts of ctDNA measured correlated with tumor volume during the course of therapy, identified patients with residual disease after treatment, and better detected response to therapy compared to radiographic methods.
As this method may also allow cancer screening and genetic identification of locally advanced and metastatic tumors without needing a biopsy, it could be used in the clinic for personalized cancer treatment.