About this document "ctDNA MRD assay (Signatera™)": Define MRD

It refers to the small number of cancer cells that may remain in the body during or after treatment, even when a patient appears to be in remission.

Based on ASCO (American Society of Clinical Oncology) guidelines, MRD testing is becoming increasingly important in cancer care because:

1. It can detect very small amounts of remaining cancer cells that traditional imaging might miss
2. It can help identify potential recurrence earlier than conventional methods

Specifically for the Signatera™ test described in this document:

• It is a blood-based ctDNA (circulating tumor DNA) test
• Its purpose is explicitly stated as detecting "molecular residual disease/recurrence months before imaging"
• It is currently being used in clinical trials for Stage II-III post-operative colorectal cancer patients

The American Cancer Society notes that MRD testing through methods like ctDNA analysis represents an emerging approach to monitoring cancer patients after treatment, though it's important to note that according to the document, this specific test is still considered investigational and is not yet covered by insurance.

Remember: Always consult with your healthcare team about the appropriateness and interpretation of any MRD testing for your specific situation.