Colorectal Cancer Survivorship: Follow-Up Questions

This page is for people who have finished treatment for colon cancer and want to understand their follow-up care. The NCI summary it draws on covers colon cancer, so rectal cancer may differ. It covers what NCI says about the evidence for follow-up, the CEA blood test, the pathology report, lifestyle findings, and questions to bring to visits.

NCI's health-professional summary is candid that the science behind follow-up schedules is not settled. Its opening line on the subject is blunt. Limited data, and no high-level evidence, are available to guide patients and physicians on surveillance (regular checkups and tests to look for cancer coming back) after surgery and adjuvant therapy (extra treatment given after surgery).

The American Society of Clinical Oncology and the National Comprehensive Cancer Network each recommend specific surveillance strategies. But NCI's PDQ summary adds points that are rarely quoted. Periodic evaluations may lead to finding recurrent disease earlier. But that monitoring does little to lower the overall death rate. The reason is that few people whose colon cancer comes back have small areas of spread that can still be cured. And to date, no large-scale randomized trial has shown an overall survival benefit for standard monitoring programs after surgery.

The summary goes further. The best regimen and frequency of follow-up examinations are not well defined. The effect on survival is unclear, and the quality of the data is poor.

None of that means skipping follow-up. It means the schedule is a judgment call built on guideline consensus. Keep your follow-up visits, and ask your team which schedule applies to you. It is also worth knowing before assuming that more scans must mean better outcomes.

Carcinoembryonic antigen (CEA) is a protein measured in the blood and used often in colon cancer management. The PDQ cites a review of the marker with three specific conclusions:

• A CEA level is not a valuable screening test for colorectal cancer, because of the large number of false-positive and false-negative reports.
• CEA testing after surgery should be restricted to people who could have surgery to remove (resect) liver or lung metastases, meaning areas of spread.
• Routine use of CEA levels alone for monitoring response to treatment is not recommended.

That second point is the one that changes conversations. The logic is surgical. The reason to catch a rising CEA is that something can be done about it. What can be done is removing a liver or lung metastasis. For someone who would not be a candidate for that surgery, the role of the test is different. It is fair to ask directly why it is being drawn.

CEA does one thing clearly. A raised CEA before treatment points to a worse outlook (prognosis).

Prognosis in colon cancer rests on three features, and these form the basis of every staging system for the disease:

• How far the tumor penetrated through the bowel wall.
• Whether lymph nodes were involved.
• Whether distant metastases are present.

Two events at presentation are separately listed as indicators of poor prognosis: bowel obstruction and bowel perforation.

One molecular finding cuts the other way. Microsatellite instability is also linked to hereditary nonpolyposis colorectal cancer. It has been associated with better survival, independent of tumor stage. That came from a population-based series of 607 patients younger than 50 with colorectal cancer. Many other markers have been looked at after the fact. Those include loss of part of chromosome 18 (18q) and levels of an enzyme called thymidylate synthase. Most have not been validated in advance.

Age is not itself a treatment factor. The PDQ summary states that treatment decisions depend on physician and patient preferences and on stage, rather than on the patient's age.

The numbers in the next few sections come from studies that compare groups. A relative risk or hazard ratio compares how often deaths or other events happen in one group against another. The "95% CI" (confidence interval) shows the likely range of the true value.

A meta-analysis of seven prospective cohort studies looked at physical activity before and after a colorectal cancer diagnosis. Two comparisons stand out.

People who did any physical activity after diagnosis, compared with none, had a relative risk of 0.74 for colorectal cancer-specific mortality. A relative risk below 1 means a lower risk than the comparison group. The 95% confidence interval, the range the true value likely falls in, ran 0.58 to 0.95, with P = .02. People doing a high amount of activity, versus a low amount, had a relative risk of 0.65. That interval ran 0.47 to 0.92, with P = .01.

Note what the comparison is. The first figure is any activity against none. These are observational findings, and the PDQ says they have not been confirmed by randomized trials.

Two prospective observational studies drew on patients enrolled in CALGB-89803, an adjuvant chemotherapy trial for stage III colon cancer.

Stage III patients in the highest fifth of dietary glycemic load had an adjusted hazard ratio (a comparison of event rates over time between groups) for overall survival of 1.76 (95% CI, 1.22–2.54; P < .001), against the lowest fifth. The PDQ also reports a Western dietary pattern result from these studies. Its comparison is worded unclearly, so this page does not repeat it.

The Cancer Prevention Study II Nutrition Cohort followed 2,315 people diagnosed with colorectal cancer. Red and processed meat intake before diagnosis was linked to a higher risk of death. The relative risk was 1.29 (95% CI, 1.05–1.59; P = .03). Red meat eaten after diagnosis was not linked to overall mortality.

That before-and-after split is unusual, and worth carrying into a conversation. It complicates the instinct that changing diet after treatment must be the lever.

The PDQ attaches a warning to all of it. Cohort studies have suggested diet or exercise may improve outcomes. No prospective randomized trials have confirmed those findings. The cohort studies had many openings for unintended bias, and caution is needed when using their data.

A prospective cohort study examined aspirin use after a colorectal cancer diagnosis. Regular users had a hazard ratio for colon cancer-specific mortality of 0.71 (95% CI, 0.53–0.95) and for overall mortality of 0.79 (95% CI, 0.65–0.97).

Then it gets more specific. One study looked at 964 patients with rectal or colon cancer. They came from the Nurses' Health Study and the Health Professionals Follow-up Study. Among those carrying PI3K variants, regular aspirin use was linked to a hazard ratio for death from any cause of 0.54 (95% CI, 0.31–0.94; P = .01).

All of that is graded as cohort-level evidence, not trial evidence. Aspirin also carries bleeding risk. So this is a question for the treating team, not a conclusion to act on alone. What makes it worth raising is the PI3K angle. That is a concrete, testable molecular question rather than general lifestyle advice.

• Which guideline is this surveillance schedule following — ASCO, NCCN, or something else — and what does it specify for this stage?
• Would I be a candidate for surgery to remove a liver or lung metastasis if one were found? If not, what is the CEA for?
• What was my pretreatment CEA, and what is it now?
• What did the pathology report say about depth of invasion through the bowel wall, and how many nodes were examined and involved?
• Was there obstruction or perforation at presentation?
• Was microsatellite instability or mismatch repair testing done, and what did it show?
• Was PI3K status tested, and is aspirin worth discussing given my bleeding risk?
• When is the next colonoscopy, and who is responsible for scheduling it?

• Call 911 or go to an emergency department if you have a lot of blood in your stool, black and tarry stool, or you vomit blood or material that looks like coffee grounds. Do the same if bleeding comes with dizziness, chest pain, trouble breathing, or severe belly pain (MedlinePlus). Do not drive yourself. Even a small amount of blood in your stool needs a call to your care team right away.
• Call your care team right away if you notice a new symptom or a change in your health between visits, or a symptom that will not go away. NCI says to report problems to your doctor immediately. A new symptom does not always mean the cancer has come back (NCI).
• Still on chemotherapy? CDC says to call your doctor right away, day or night, for a temperature of 100.4°F (38°C) or higher (CDC). Chills, a sore throat, mouth sores, or burning when you urinate also need a right-away call (NCI, CDC). Fever can be the only sign of infection, and a normal temperature is not a reason to wait.

Related pages: colorectal cancer covers the disease itself. What a survivorship care plan is covers how these schedules get written down and shared with primary care. And fear of recurrence covers the part surveillance does not treat.

• NCI PDQ — Colon Cancer Treatment, health professional version
• NCI — Follow-Up Care After Cancer Treatment
• MedlinePlus — Gastrointestinal bleeding
• CDC — Watch Out for Fever
• NCI — Infection and Neutropenia during Cancer Treatment
• CDC — Watch Out for Fever
• CDC — Signs and Symptoms of Infection