The BESPOKE CRC study will prospectively enroll patients who have undergone surgery for stage I to IV colorectal cancer (CRC) and who have residual formalin-fixed paraffin-embedded (FFPE) tissue available will provide FFPE and whole blood samples. Patients will receive SIGNATERA™ test results and may be recommended for post-operative systemic therapy or observation by their treating clinician. Patients will be followed for up to two years with periodic whole blood collection. The study also has a control arm that will consist of matched Stage I to IV CRC cases that have a minimum of least 2 years clinical follow-up data.

Primary Objectives:

• Examine the impact of SIGNATERA™ on adjuvant treatment decisions
• Determine the rate of recurrence of patients diagnosed with CRC while asymptomatic using SIGNATERA™

Secondary objectives:

• Molecular residual disease clearance as assessed by SIGNATERA™
• Percent of patients undergoing surgery for oligometastatic recurrence
• Survival in patients treated with adjuvant versus no adjuvant chemotherapy in patients with SIGNATERA™ negative test results
• Overall survival
• Impact of SIGNATERA™ test results on patient quality of life

Inclusion criteria:

1. 18 years of age or older.

2. Planning or undergone surgical resection of adenocarcinoma of the colon or rectum.

3. Diagnosis of Colorectal cancer that falls into one of the below categories:

   1. Stage I to IV disease.
   2. Stage IV with oligometastatic disease eligible for post-operative systemic therapy.

4. Selected by their healthcare provider to receive the SIGNATERA™ test according to the current evidence-informed schedule as part of their routine practice.

5. ECOG performance status ≤ 2

6. Clinically eligible for post-operative systemic therapy.

7. Able to tolerate venipuncture for research blood draw(s).

8. Able to read, understand and provide written informed consent .

9. Willing and able to comply with the study requirements.

Exclusion Criteria:

1. Pregnant or breastfeeding.
2. Prior history and treatment for any cancer within the past year or has another active cancer, with the exception of non-melanoma skin cancer
3. Has a known rare inherited genetic condition, with the exception of lynch syndrome
4. Has initiated post-operative systemic therapy.
5. Neuropathy > grade 2.
6. History of bone marrow or organ transplant.
7. Medical condition that would place the patient at risk as a result of blood donation, such as bleeding disorder .
8. Serious medical condition that may adversely affect ability to participate in the study.

Control Arm Inclusion criteria:

1. 18 years of age or older at time of diagnosis.

2. Diagnosis of Colorectal cancer that falls into one of the below categories:

   1. Stage I to IV disease.
   2. Stage IV with oligometastatic disease eligible for post-operative systemic therapy.

3. Were clinically eligible for chemotherapy at full recommended doses per Health Care Provider.

4. Received treatment no more than 3 years prior to study start date.

5. Have a minimum of least 2 years clinical follow-up data or reached a progression event.

Control Arm Exclusion criteria:

1. Female patients that were pregnant or breastfeeding during historical control collection period.
2. Per investigator, was not clinically eligible for post-operative systemic therapy.
3. Had an ECOG performance status ≤ 2 at time of diagnosis.

Patients who have been diagnosed with Stage I, Stage II, Stage III or Stage IV colorectal cancer.