Minimal residual disease assessment in colorectal cancer (MiRDA-C).

Abstract

TPS236 Background: Detection of circulating tumor DNA (ctDNA) in the bloodstream is emerging as a novel marker for identifying of radiographically occult microscopic or minimal residual disease (MRD) in colorectal cancer (CRC) patients (pts) after curative intent treatments. Accumulating data suggest that ct-DNA defined MRD is a highly specific prognostic biomarker for future recurrences with a lead time of several months and prospective clinical trials are being conducted using ct-DNA defined MRD as an integral biomarker for improving risk stratification for adjuvant chemotherapy decision making. However, large scale, prospective data regarding kinetics of ctDNA-defined MRD with accurate pre-analytical methodology for plasma isolation and paired clinical data are limited. Methods: In this multi-center, prospective observational study, 1,000 pts with resectable CRC (stages II – IV) without other active malignancies undergoing therapy with curative intent will be enrolled any time from time of diagnosis up to start of adjuvant therapy (or ≤ 3 months post curative surgery, whichever is earlier). All therapeutic and surveillance visits decisions are at the discretion of the treating physicians. Serial biospecimens including blood (in Cell-Free DNA BCT tubes) to be processed to plasma and buffy coat in ≤ 2 days and formalin fixed tumor tissue will be collected at key time points until the time of radiographic recurrence or up to 5 years of surveillance. Blood draws will be at study entry, after each line of neoadjuvant therapy, post-surgery, during and after adjuvant therapy in addition to each surveillance visit. These blood draws will be coordinated with pts’ standard of care visits in order to minimize additional venipunctures. Relevant clinical data including demographics, cancer history, treatment details and outcomes, serum tumor markers and genomic data will be collected at each time point. Samples will be evaluated retrospectively with a primary objective of evaluating sensitivity and specificity of post-operative MRD for radiographic recurrences utilizing Guardant Health’s Reveal assay. Other key objectives include evaluating ctDNA kinetics with neoadjuvant and adjuvant therapies and to correlate with outcomes. The study is active, and enrollment is ongoing. Clinical trial information: NCT04739072.