Prospective study of molecular residual disease and efficacy of adjuvant chemotherapy in patients with colorectal cancer

Relapse is seen in more than 30% of patients who receive standard-of-care treatment for resectable colorectal cancer (CRC). Circulating tumor DNA (ctDNA) analysis may enable postsurgical risk stratification and adjuvant chemotherapy (ACT) decision-making. The Japanese multicenter observational GALAXY study analyzed postsurgical ctDNA in 1,039 patients with stage II-IV resectable CRC. In this cohort, with a median follow-up of 16.74 months (range 0.49-24.83), ctDNA positivity at 4 weeks after surgery was associated with higher recurrence risk (HR 10.0; p<0.0001) and was the most significant prognostic factor associated with recurrence risk in patients with stage II or III CRC (HR 10.82; p<0.001). Postsurgical ctDNA positivity identified patients with stage II or III CRC who derived benefit from ACT (HR 6.59; p<0.0001). The authors conclude that the results of the study support the use of ctDNA testing to identify patients who are at elevated risk of recurrence and are likely to benefit from ACT.