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Monitoring for Recurrence

After you finish active treatment, you will continue to see your medical provider for follow-up care. This care includes managing side effects, assessing your overall health, and monitoring for a cancer recurrence. This is also known as “surveillance.” Surveillance is also used to check how well you are responding to treatment.

When you see your medical provider, they may use several different tools to assess:

  • How well you are responding to treatment (if you are currently in treatment)

  • If further treatment or a change may be needed

  • Whether there are signs that the cancer has spread, returned, or progressed

Surveillance strategies aimed at early detection increase the chance that cancer can be treated and cured. New tools are available to detect traces of cancer in the blood.

The odds for cancer recurrence are bigger if the initial tumor was diagnosed at an advanced stage.

Cancer Monitoring Recommendations

Now that you have completed your treatment—whether your treatment plan included surgery, chemotherapy, and/or radiation—you and your medical team should discuss your follow-up care plan. The plan will include ongoing monitoring and should also address lifestyle and emotional needs.

  1. Talk with your doctor (oncologist) about your risk of cancer coming back (recurrence) and how it affects your follow-up care plan and testing schedule.

  2. Keep your scheduled follow-up visits. These visits are important. While you cannot guarantee that cancer will not come back, routine visits will increase your chance of catching a recurrence earlier, making it easier to treat.

  3. Ask your care team about new tests that may be available for early detection of recurrence. There are many new non-invasive technologies (e.g. blood tests) that make it easier and faster to find cancer when it recurs.

  4. Find out if you can go to a survivorship and wellness clinic for your follow-up visits. While many survivors get follow-up care with their oncologist or with their primary care doctor, these clinics have specialized experts who can also help with nutrition, physical activity, and other health needs.

  5. Talk to your medical team about your fears and anxiety. Some patients feel lonely after the frequent visits they are used to with the care team. Our certified patient and family support navigators are available anytime to talk through your concerns.

Circulating Tumor DNA (ctDNA)

What is ctDNA?

Circulating tumor DNA (ctDNA) refers to small pieces of DNA from cancer tumor cells that are shed into the bloodstream. Since ctDNA can be detectable at all stages of cancer, it can be useful in the monitoring the presence of cancer cells in your body. These test are primarily used in stage II and stage III colon and some stage II rectal cancers.

How does ctDNA testing work?

ctDNA can be detected in blood samples and can provide information for survivors who are currently receiving treatment and those who are finished with treatment. Depending on the ctDNA test, it will use either blood or both blood and tissue to provide information on short fragments of DNA that are specific to the tumor. Detection of these fragments of DNA may show that you are at a higher risk of developing recurrent cancer and/or can be used by doctors to guide effective treatment strategies. 

  • SIGNATERA - personalized Circulating Tumor DNA (ctDNA) test: Signatera is a clinically-validated, doctor-prescribed, residual disease test that can be designed only for you. Design of the Signatera test using information from your tumor allows for highly accurate detection of very small amount of ctDNA. The test compares DNA sequences between your cancer cells and normal cells to identify which mutations are only present in your tumor. Your personalized Signatera test will reveal if your blood contains any ctDNA fragments that match the mutations. A negative result indicates that tumor DNA was not detected in your blood. Repeat testing with SignateraTM is important because a negative result may change over time. If you have a positive result, there is a 97% chance that your cancer has returned. Your doctor will speak with you about next steps, which may include ordering additional tests such as CEA, CT, MRI, or PET scans to determine whether the cancer has returned.

  • COLVERA - Circulating Tumor DNA (ctDNA) test: Colvera is a clinically-validated, doctor-prescribed blood test designed to identify small fragments of DNA fragments that are methylated (changed) and associated with colorectal cancer, known as ctDNA, which may leak from a tumor into the bloodstream. The presence of ctDNA may show residual disease after a patient has been treated for colorectal cancer. If this test is positive, your doctor may order additional tests such as CT, MRI, or PET scans to determine whether the cancer has recurred. This test is currently done alongside CEA.

How is ctDNA used?

After completing treatment

  • ctDNA testing is an option for survivors who have finished curative treatment who are stage II or stage III. Along with CEA, ctDNA is currently approved for monitoring disease recurrence in survivors of stage II and III colorectal cancer. Additional tests such as CT, MRI, or PET scans may be necessary to locate the cancer recurrence. 

After surgery

  • ctDNA can also be used to monitor any residual (leftover) cancer after surgery in low-risk stage II and III colon cancer and stage IIA rectal cancer. This can determine if adjuvant (after surgery) chemotherapy is needed in low-risk patients. Chemotherapy is standard of care for high-risk, more advanced colon cancer, and high-risk rectal cancer which includes radiation with or without chemotherapy.

After Treatment

Questions to Ask Your Doctor

After you have finished treatment, you may have a number of questions swirling in your mind. Here are some questions to consider asking your healthcare team to make sure you are clear on your next steps. 

General Questions

  • What follow-up tests will I need and how often will I need them?

  • Is there a cancer survivorship clinic where I can go for my follow-up care?

  • Which doctors will be coordinating my follow-up care?

  • If I move or need to switch doctors, how do I continue my recommended follow-up care schedule?

  • What is my risk of recurrence?

  • What signs and symptoms should I watch for?

Types of Testing:

  • How can a blood test that measures ctDNA be helpful as a part of my follow-up care?

  • How often should I get ctDNA testing?

  • How does ctDNA testing compare with CEA testing? And how often should those tests be done?

  • What does it mean when ctDNA results are negative?

  • What does it mean when ctDNA results are positive? What are the next steps?

  • How often do I need a CT scan? Where will it be done?

  • How often do I need a colonoscopy? Who will do it and where?

  • What type of follow-up care do I need beyond five years after treatment?

  • Where can I find more information about follow-up care? 

Comparison of Cancer Monitoring Methods



CEA is a protein and, for some people, is a biomarker for the presence of colorectal cancer cells in the body. CEA has been used to monitor colorectal cancer survivors for over 30 years and can be predictive of recurrence in some people but not in others. The CEA level can be used to show if disease remains after treatment or if the cancer has come back. CEA is expected to decrease after surgery but if it remains above normal it is an indication that cancer remains in the body. There are also certain factors such as smoking that may increase CEA. If your CEA increases you will need further testing such as CT, MRI, or PET scans to see where the cancer is.

Circulating tumor DNA (ctDNA) 

Circulating tumor DNA (ctDNA) refers to small pieces of DNA that originate from tumor cells and are shed in the bloodstream. Detection of ctDNA in the blood indicates that there are cancer cells in your body. There are currently two available ctDNA tests that look at different small DNA fragments.


Computed tomography (CT) scan

A CT scan is a series of detailed pictures of areas inside the body, taken from different angles. The pictures are created by a computer linked to an x-ray machine. This is sometimes also called computerized axial tomography, computed tomography (CT scan), or computerized tomography.

Magnetic Resonance Imaging (MRI) 

MRI is a specialized way to look at the organs of the body using magnetic energy and a computer.

Positron emission tomography (PET) scan 

A PET scan is a specialized way to look at the organs of the body according to how fast they use sugar and it can be used to detect cancerous cells. Cancer cells have a high metabolism and use sugar faster than non-cancerous cells.



Colonoscopy is a procedure that allows a doctor (gastroenterologist) to view the inside of the colon and rectum. A colonoscope is a four-foot-long, thin, flexible tube with a camera and a source of light at its tip. The tip of the colonoscope is inserted into the anus and is advanced slowly to visualize the rectum and the entire colon. If polyps are seen, they may be removed during the procedure.

Follow-up Schedule


Stage 1

Stage 2/3

Stage 4

Physical Examination


Years 1 & 2: Every 3-6 months

Years 3-5: Every 6 months

Years 1 & 2: Every 3-6 months

Years 3-5: Every 6 months 


Years 1, 3 & 5 Years 1, 3 & 5 Years 1, 3 & 5

Test for CEA


Years 1 & 2: Every 3-6 months

Years 3-5: Every 6 months 

Years 1 & 2: Every 3-6 months

Years 3-5: Every 6 months 

CT Imaging: chest,
abdominal, pelvic areas

  Every 6-12 months for 5 years

Years 1 & 2: Every 3-6 months

Years 3-5: Every 6 months 

Managing the disease

Learn what to expect and how to manage colorectal cancer (colon and rectal cancer) every step of the way. 

Emotional Help

Learn about how to maintain good emotional health throughout your cancer journey. Just as cancer affects your physical health, it can bring up a wide range of feelings you’re not used to dealing with. 

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