Correlation Between Diagnosis-to-Treatment Interval and Circulating Tumor DNA Levels in DLBCL

Short diagnosis-to-treatment (DTI) and circulating tumor DNA (ctDNA) levels in patients with diffuse large B-cell lymphoma (DLBCL) are indicative of tumor burden at baseline, according to a study published in the Journal of Clinical Oncology, and this information may be useful for mitigating patient selection bias in clinical trials.

In this multicenter trial, patients with DLBCL were assessed for pretreatment ctDNA levels per Cancer Personalized Profiling by Deep Sequencing. The researchers evaluated the correlation between pretreatment ctDNA levels and DTI, total metabolic tumor volumes (TMTVs), the International Prognostic Index (IPI), and patient outcome.

Final analysis included 267 patients. Patients with short DTI were more likely to have advanced disease (P<0.001) and higher IPI (P<0.001). DTI was inversely correlated with TMTV (P<0.001). The researchers found that DTI and ctDNA were indicative of disease burden, as significant correlations were observed between pretreatment ctDNA levels and stage, IPI, and TMTV (P<0.001 for all). Pretreatment ctDNA levels were observed in patients with shorter DTI and were predictive of short DTI, independent of the IPI. In univariable analysis, each risk factor had a significant correlation with event-free survival, but in multivariable Cox regression analysis, ctDNA level predicted event-free survival, independent of DTI or IPI.

“Short DTI largely reflects baseline tumor burden, which can be objectively measured using pretreatment ctDNA levels. Pretreatment ctDNA levels therefore have utility for quantifying and guarding against selection biases in prospective DLBCL clinical trials,” the study authors concluded.