You’ve completed your surgery and, if prescribed, your chemotherapy. It’s normal to be wondering: What happens next? The next step is called follow-up (or monitoring). These are scheduled checkups to detect a possible relapse as early as possible. Here’s what these checkups typically include and how often they’re scheduled. This is general information: your exact schedule will be determined by your care team based on your stage, your risk, and your hospital.
The Purpose of Follow-up Care (and Its Limitations)
The goals are to detect a recurrence early, monitor treatment side effects, and examine the colon for any new polyps or tumors. The 2023 Spanish SEOM-GEMCAD-TTD guidelines state that monitoring after treatment allows for earlier detection of relapses and enables more patients to undergo curative surgery.
Now, to be honest: more testing does not always mean better survival. Several large trials (COLOFOL, FACS, GILDA) failed to demonstrate that more frequent CT scans and CEA testing reduce mortality, although more relapses were treated with curative intent in the intensive follow-up group. That is why the guidelines provide ranges rather than a single, universal schedule. It’s not that your team is being negligent—it’s just that the evidence doesn’t specify an exact schedule.
The tests, one by one
| Test | What it measures | Recommended frequency in the guidelines |
|---|---|---|
| Consultation with examination | Symptoms, treatment effects, general condition | Every 3–6 months for the first 2–3 years; thereafter, every 6–12 months until age 5 |
| CEA testing | A blood marker that may rise if there is a relapse | Same as checkups: every 3–6 months at first, then less frequently |
| CT scan of the chest, abdomen, and pelvis | Metastases in the liver, lungs, or other areas | Every 6–12 months, for up to 5 years according to the guidelines, or less frequently in some regimens |
| Colonoscopy | Polyps or a new tumor in the colon | One year after surgery; thereafter, depending on the findings |
| PET-CT | To clarify specific concerns | Not a routine test |
Consultation and testing
The European ESMO guidelines (2020) recommend follow-up visits and CAE testing every 3–6 months for 3 years and every 6–12 months in years 4 and 5. The NCCN (U.S.) guidelines for stages II and III recommend follow-up visits and CEA testing every 3–6 months for the first 2 years and every 6 months for the following 3 years, up to a total of 5 years.
In addition to the CEA, the SEOM explains that follow-up typically includes a blood test with a complete blood count and biochemical panel. This helps assess, for example, how well the liver is functioning.
Be careful with the CEA: it’s only indicative. The SEOM emphasizes that your doctor interprets it in conjunction with your symptoms and other test results, and that an isolated increase does not, on its own, mean you need to change your treatment. ESMO notes that it can produce false positives (7–16%) and false negatives (up to 40%). If you’re interested, there’s an entire guide on high CEA levels: what they mean—and what they don’t.
CT scan of the chest, abdomen, and pelvis
This is the primary imaging test used for follow-up. The guidelines do not entirely agree:
- ESMO (2020): A chest and abdominal CT scan may be considered every 6–12 months for the first 3 years in patients at higher risk of relapse.
- NCCN: CT scans of the chest, abdomen, and pelvis every 6–12 months for up to 5 years in stage III and high-risk stage II patients.
- Proposal published in Annals of Oncology (commentary on the ESMO guidelines): follow-up visit and CEA every 3 months in the first year, then every 6 months for 3–5 years, and two CT scans at 12 and 36 months.
- The COLOFOL trial compared CT scans and CEA at 6, 12, 18, 24, and 36 months with testing only at 12 and 36 months. There was no significant difference in 10-year mortality.
That’s why you’ll see that one patient is asked to have a CT scan every 6 months and another every year. Ask your oncologist which schedule applies to you and why.
Colonoscopy
The 2023 SEOM-GEMCAD-TTD guidelines recommend a colonoscopy one year after surgery. After that, the interval depends on the findings. The NCCN recommends a repeat colonoscopy at 3 years and then every 5 years, unless an advanced adenoma is found, in which case it is repeated after one year. Full details are in our guide “Colonoscopy After Treatment: When and How Often.”
PET-CT: Not a Routine Test
Many people expect a PET scan because it “sees more.” But the SEOM is clear: it should not be performed routinely as part of follow-up care. It is only ordered in specific cases: when there are concerns about recurrence based on a CT scan, or before surgery for liver metastases to rule out other sites. Other guidelines agree that, in asymptomatic patients who have completed curative treatment, surveillance PET scans are not recommended. They are more useful, for example, when the CEA level rises and a CT scan does not provide clarity.
If you don’t have a PET scan, it doesn’t mean you’re being monitored any less closely.
If your CEA rises but your test results are normal
This happens sometimes. The NCCN states that if the CEA rises and the imaging is normal, the CT scan should be repeated every 3 months until the disease is identified or the CEA stabilizes or decreases. It’s a very frightening situation, but a high CEA level isn’t a diagnosis in itself—it needs to be confirmed with other tests.
Depending on your case: what might change
- Stage. For Stage I, the guidelines are not in agreement: ESMO proposes the same strategy as for Stages II and III, while the NCCN and ASCO do not recommend intensive surveillance. Your care team will decide.
- Rectal cancer. The guidelines are somewhat different. The ESMO rectal cancer guideline mentions, for example, follow-up visits every 6 months for 2 years, CEA testing at least every 6 months for the first 3 years, and a minimum of two CT scans during that period. If you’re on a “watch and wait” approach, follow-up is more frequent and is determined by your team (see our guide on rectal cancer).
- Operated-on metastases. If you underwent surgery for metastases with curative intent, the SEOM-GEMCAD-TTD guidelines recommend more intensive monitoring: CT scan (or MRI) and CEA every 3 months for the first 2 years and every 6 months thereafter.
- Liquid biopsy (ctDNA). The 2023 Spanish guidelines state that there is not yet sufficient evidence to use it routinely outside of clinical trials. We explain this in our guide on liquid biopsy.
How It Typically Works in the Public Health System
Typically, follow-up is managed by your Oncology (or Surgery/Gastroenterology) department, and appointments are scheduled through the hospital. The exact schedule varies by center and autonomous community. Upon completing treatment, you should leave the appointment knowing three things:
- Which tests you’ll need and their approximate dates.
- Who schedules your appointments (the hospital, your oncologist, or your primary care physician).
- Who to call if you experience a symptom between checkups.
If you need a copy of your CT scans or lab results, you have the right to request one (guide on medical records and patient rights).
When to contact your care team without waiting for your appointment
Scheduled checkups are not a substitute for your ongoing care. This list is intended as a guide, not an exhaustive list. Contact your care team or your primary care physician if you notice:
- Blood in your stool or new, persistent changes in your bowel habits.
- Unexplained or worsening abdominal pain.
- Unexplained weight loss, worsening fatigue, or a persistent lack of appetite.
- A persistent cough, difficulty breathing, new bone pain, or yellowing of the skin or eyes.
- New lumps or swelling in the abdomen.
Go to the emergency room if you have severe abdominal pain with vomiting and are unable to pass gas or stool, significant bleeding, or a high fever if you have recently received chemotherapy (see the guide on febrile neutropenia). Do not wait until your next checkup.
The days before and after each test
It’s very common to feel nervous in the days leading up to a CT scan or lab tests—and even more so while you’re waiting for the results. This isn’t a sign of weakness; it’s a normal reaction. Ask them to explain when and how they’ll give you the results, so you don’t have to wait in the dark. The guide Fear of Relapse offers helpful strategies.
Questions to Ask During Your Appointment
- What is my screening schedule, and for how many years?
- Is my case considered high or low risk for relapse?
- When will I have my next colonoscopy?
- If my CEA level rises, what steps will we take?
- What phone number or clinic should I call if I have a symptom?
And remember: none of these tests guarantees anything on its own. They’re a safety net, and keeping them well organized helps put your mind at ease.