Asymptomatic CRC Linked to Lower ctDNA Detection, Recurrence Risk Over Symptomatic Patients

Circulating tumor DNA (ctDNA) is commonly used to measure patient prognosis, monitor disease progression, and determine treatment outcomes in patients with cancer. While it is also utilized for early cancer detection, studies of asymptomatic and symptomatic patients have demonstrated lower ctDNA detection in asymptomatic patients.

A recent study published in the British Journal of Cancer analyzed the use of ctDNA assessment in patients with asymptomatic colorectal cancer (CRC) to determine if they differ from symptomatic patients by including “low ctDNA shedding” and “less aggressive” patient subgroups.

ctDNA assessment was carried out in two independent cohorts for each cancer type. The asymptomatic CRC group consisted of 215 patients in cohort 1 and 368 patients in cohort 2, while the symptomatic CRC group consisted of 117 patients in cohort 1 and 722 patients in cohort 2.

When adjusted for tumor stage and size, the detection of ctDNA was significantly lower in asymptomatic patients than in symptomatic patients (Cohort 1: OR: 0.4, 95%CI: 0.2–0.8, Cohort 2: OR: 0.7, 95%CI: 0.5–0.9).

The recurrence risk was also lower in asymptomatic patients (Cohort 1: sHR: 0.6, 95%CI: 0.3–1.2, Cohort 2: sHR: 0.6, 95%CI: 0.4–1.0), with ctDNA-negative asymptomatic patients having the lowest recurrence risk compared to symptomatic patients (Cohort 1: sHR: 0.2, 95%CI: 0.1–0.6, Cohort 2: sHR: 0.3, 95%CI: 0.2–0.6).

Asymptomatic patients may be enriched for “low ctDNA shedding” or “low recurrence risk” subgroups. These insights can help aid in the guidance of ctDNA-based early detection initiatives, and can prompt potential de-escalation of therapy and follow-up for ctDNA-negative asymptomatic CRC patients.