Molecular residual disease and efficacy of adjuvant chemotherapy in patients with colorectal cancer

Despite standard-of-care treatment, more than 30% of patients with resectable colorectal cancer (CRC) relapse. Circulating tumor DNA (ctDNA) analysis may enable postsurgical risk stratification and adjuvant chemotherapy (ACT) treatment decision-making. We report results from GALAXY, which is an observational arm of the ongoing CIRCULATE-Japan study (UMIN000039205) that analyzed presurgical and postsurgical ctDNA in patients with stage II-IV resectable CRC (n = 1,039). In this cohort, with a median follow-up of 16.74 months (range 0.49-24.83 months), postsurgical ctDNA positivity (at 4 weeks after surgery) was associated with higher recurrence risk (hazard ratio (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). Furthermore, postsurgical ctDNA positivity identified patients with stage II or III CRC who derived benefit from ACT (HR 6.59, P < 0.0001). The results of our study, a large and comprehensive prospective analysis of ctDNA in resectable CRC, support the use of ctDNA testing to identify patients who are at increased risk of recurrence and are likely to benefit from ACT. In the observational GALAXY arm of the CIRCULATE-Japan study, among 1,049 patients with stage II-IV colorectal cancer, those with presence of circulating tumor DNA (ctDNA) after tumor resection have a high recurrence risk and are likely to benefit from adjuvant chemotherapy.

Automated summary

Circulating tumor DNA (ctDNA) analysis can help with risk stratification and treatment decisions for patients with resectable colorectal cancer (CRC). The study found that postsurgical ctDNA positivity was associated with higher recurrence risk and was the most significant prognostic factor for patients with stage II or III CRC. Furthermore, ctDNA positivity identified patients who derived benefit from adjuvant chemotherapy.