Minimal Residual Disease Testing for the Early Detection of Cancer Recurrence in Resectable Stage II-IV Colorectal Cancer Patients

Inclusion Criteria:

* Documented written informed consent of the participant
* Age: ≥ 18 years
* Diagnosis of stage II, III or IV colorectal cancer (any gender) if enrolled post-operatively. If a treatment naïve patient is enrolled pre-operatively and determined to be pathological stage I, the patient will be replaced
* Patient who are to undergo a curative intent surgery or have undergone a curative resection and are presenting for surveillance
* Patient identified as an appropriate candidate for Signatera® testing as a standard of care MRD surveillance assay
* Patient willingness to continue Signatera® assay every 3 months for 2 years in the first 2 years after resection and every 6 months for years 3, 4, 5 after resection, as performed by standard of care testing. In addition, the patients should be willing to provide blood samples for Haystack MRD testing at the same intervals of Signatera®, along with willingness to allow access to archival tissue to allow for Haystack MRD assay personalization. Surveillance with ctDNA should be initiated between 3 to 10 weeks from surgery
* Adequate availability of archival tissue or anticipated pathological viable tissue. All untreated primary resection would be expected to have adequate tissue. Patients with resected metastatic disease should have either previously resected primary that is amenable for tumor informed MRD testing or should have adequate archival metastasectomy samples
* Patients with total neoadjuvant therapy (TNT) for rectal cancer and complete clinical response with plans of watchful waiting may also be enrolled as long as there is adequate tissue from prior endoscopic biopsies to allow for Signatera® and Haystack MRD assays

Exclusion Criteria:

* Inability to safely provide sequential blood samples
* Clinical evidence of unresected metastatic disease
* Inability to give informed consent