Smart Measurement of Circulating Tumor DNA

This study is investigating whether a blood test that detects circulating tumor DNA (ctDNA) — tiny fragments of cancer DNA found in the bloodstream — can be used to monitor cancer in people with Lynch syndrome who have recently been diagnosed with cancer but have not yet started treatment. **You may be eligible if...** - You have confirmed Lynch syndrome (a genetic condition that increases cancer risk), meaning you carry a mutation in an MMR gene or EPCAM gene, OR your cancer tested positive for microsatellite instability - You are 18 or older - You have been diagnosed with any form of cancer and have not yet started treatment **You may NOT be eligible if...** - You do not have confirmed Lynch syndrome or MSI-H (microsatellite instability high) cancer - You have already begun cancer treatment - You are under 18 Talk to your doctor to see if this trial is right for you.