Who this is for
Stage III colon cancer recurrence is one of the greatest concerns for patients after surgery. Chemotherapy remains the foundation of treatment, but new evidence suggests that structured exercise and aspirin for selected patients may provide additional ways to reduce the risk.
This article is for you if:
- You have been diagnosed with high-risk stage III colon cancer.
- Your pathology report mentions T4 or N2 disease.
- You have undergone surgery and are preparing for chemotherapy.
- You want to know whether exercise or aspirin could further reduce the chance of the cancer returning.
Clinical observation
Recently I saw a gentleman who travelled from Iraq seeking a second opinion.
One of the most difficult conversations in oncology is telling someone that they have a cancer that caused almost no symptoms until it became quite advanced.
This is unfortunately very common in colon cancer.
Many patients feel perfectly well. They continue working, exercising and spending time with their families. Then a routine test or an unexpected symptom leads to a diagnosis that comes completely out of the blue.
In his case, the cancer had spread to multiple lymph nodes.
That alone is concerning.
However, what worried me even more was the T stage.
When I explain this to patients, I often describe the bowel as a hollow tube. The cancer starts on the inside surface where food and waste pass through the bowel. Over time it grows deeper through the bowel wall.
In his case, the cancer had grown through the bowel wall and reached its outer surface.
In medical language, this was a T4 tumour.
The cancer had also spread to multiple nearby lymph nodes.
This was classified as N2 disease.
Together, T4 and N2 placed him in one of the highest-risk groups within stage III colon cance
The question he asked was simple:
“I’ve had surgery. I’m willing to do chemotherapy. What else can I do to improve my chances?”
What surprised me
For many years, the plan after surgery was relatively straightforward:
- Chemotherapy
- Follow-up appointments
- Blood tests and scans
That was largely the end of the conversation.
Today, we have something different.
We now have evidence from three separate areas:
- Modern oxaliplatin-based chemotherapy
- Structured exercise after chemotherapy
- Aspirin for carefully selected patients whose cancers have particular genetic changes
What surprised me is that two of these interventions are remarkably simple.
One involves moving your body.
The other involves a tablet that costs only a few cents per day.
Neither replaces chemotherapy.
However, both may contribute meaningful additional benefit.
Why this matters
Many patients assume that once chemotherapy finishes, there is nothing more they can do.
That is no longer entirely true.
No intervention can guarantee that colon cancer will not return. However, evidence now shows that there may be additional safe and practical ways to improve outcomes after standard treatment.
The important question is not simply:
“What can everyone with colon cancer take or do?”
The better question is:
“Which evidence-based strategies are suitable and safe for this particular patient?”
What do T4 and N2 mean?
The letters and numbers in a pathology report describe how far the cancer has grown and whether it has reached nearby lymph nodes.
T4 disease
T4 means that the cancer has grown through the bowel wall and has either:
- Reached the outer surface of the bowel, or
- Grown directly into a nearby organ or structure
N2 disease
N2 means that cancer was found in four or more nearby lymph nodes.
T4 or N2 disease carries a higher risk of recurrence than lower-risk forms of stage III colon cancer.
However, a higher risk does not mean that the cancer will definitely return.
Stage III colon cancer remains potentially curable, and treatment after surgery can meaningfully improve the chance of remaining cancer-free.
Step one: chemotherapy
The foundation of treatment is surgery followed by chemotherapy.
Common chemotherapy regimens include:
- FOLFOX
- CAPOX, also known as XELOX
These treatments combine oxaliplatin with a medicine called a fluoropyrimidine.
Chemotherapy is given after surgery to destroy cancer cells that may remain in the body but are too small to appear on a scan. This reduces the risk of the cancer returning and improves long-term outcomes.
For patients with T4 or N2 disease, six months of oxaliplatin-based chemotherapy is commonly offered.
However, the exact regimen and duration should be personalised.
The decision depends on:
- the pathology findings
- the chemotherapy regimen
- the patient’s age and general health
- the risk of side effects
- how well treatment is tolerated
- the patient’s preferences
The aim is to provide enough treatment to reduce recurrence risk while avoiding unnecessary long-term harm.
Step two: structured exercise
The CHALLENGE trial changed the way oncologists think about exercise after colon cancer treatment.
For years, studies suggested that physically active patients had better outcomes.
However, there was an important unanswered question:
Did exercise itself improve outcomes, or were healthier people simply more likely to exercise?
The CHALLENGE trial helped answer that question.
Researchers enrolled 889 patients with high-risk stage II or stage III colon cancer who had completed surgery and chemotherapy.
The patients were randomly assigned to receive either:
- A structured exercise program, or
- Standard health-education information
The structured exercise program continued for three years.
This was not simply advice to “be more active.”
Patients received:
- An individualised exercise plan
- Regular coaching
- Behavioural support
- Ongoing review of their activity and progress
The program was adjusted according to each patient’s health, fitness and abilities.
Step three: aspirin for selected patients
The ALASCCA trial examined whether aspirin could reduce the risk of colorectal cancer returning after surgery.²
Importantly, aspirin was not given to every patient.
The trial included patients whose cancers contained particular genetic changes affecting the PI3K pathway. This pathway helps control how cells grow, divide and survive.
Patients received either:
- Aspirin 160 mg once daily, or
- A placebo
Treatment continued for three years.
The strongest evidence was seen in patients whose cancers contained particular PIK3CA hotspot mutations.
A similar benefit was also observed among patients with some other genetic changes affecting the PI3K pathway.
However, aspirin is not suitable for everyone.
Before recommending it, doctors must consider:
- Whether the tumour has a relevant genetic change
- The patient’s risk of bleeding
- Previous stomach ulcers or gastrointestinal bleeding
- Other medicines, including blood thinners
- Kidney and liver function
- Aspirin allergy
- Other medical conditions
Patients should not begin taking aspirin for colon cancer without first discussing it with their oncologist.
Key results
Structured exercise
After five years:
- 80.3% of patients in the structured exercise group were alive without a cancer recurrence, a new cancer or death from another cause.
- This compared with 73.9% of patients who received health-education information alone.
After eight years, overall survival was:
- 90.3% with structured exercise
- 83.2% with health education alone
The trial demonstrated a significant improvement in disease-free survival, with findings also consistent with longer overall survival.
Aspirin
Among patients with PIK3CA hotspot mutations, the estimated chance of recurrence within three years was:
- 7.7% with aspirin
- 14.1% with placebo
This means that aspirin approximately halved the relative risk of recurrence in this biomarker-selected group.
However, this result should not be applied automatically to every patient with colon cancer.
Reducing stage III colon cancer recurrence: Putting everything together
Surgery and chemotherapy remain the foundation of treatment for high-risk stage III colon cancer.
Structured exercise may provide an additional benefit after chemotherapy.
For selected patients whose tumours contain particular PI3K pathway changes, aspirin may also become an important discussion.
However, we cannot simply add the benefits from these separate studies together.
No clinical trial has tested chemotherapy, structured exercise and biomarker-guided aspirin as one combined treatment strategy.
The potential benefit for an individual patient will depend on:
- The cancer stage and pathology
- The number of involved lymph nodes
- The tumour’s genetic profile
- The treatment already received
- The patient’s general health
- Whether exercise can be performed safely
- The possible risks and benefits of aspirin
The aim is not to promise a particular outcome.
The aim is to identify every safe and evidence-based opportunity that may improve the patient’s chances.
What do these results actually mean?
One of the most important lessons I have learned as an oncologist is that outcomes are rarely determined by a single decision.
It is often the accumulation of multiple good decisions.
- A successful operation.
- Appropriate chemotherapy.
- Maintaining physical activity.
- Optimising body weight.
- Management of treatment side effects.
- Regular follow-up.
- Considering aspirin when biologically appropriate.
These steps may work together to improve a patient’s overall chances.
However, it is equally important to say this clearly:
If cancer returns, it does not mean that the patient failed, exercised too little or made the wrong decision.
Cancer biology remains powerful and sometimes unpredictable.
The purpose of these strategies is to improve the odds wherever possible—not to place responsibility or blame on the patient.
A personalised discussion with the treating oncologist can help identify which strategies for reducing stage III colon cancer recurrence are appropriate and safe for each patient.
Key takeaways
- T4 or N2 stage III colon cancer carries a higher risk of recurrence
However, it remains potentially curable, and postoperative chemotherapy can significantly improve outcomes. - Structured exercise can make a meaningful difference
The CHALLENGE trial showed that a supported three-year exercise program improved disease-free and overall survival after chemotherapy. - Aspirin may help selected patients
The benefit appears strongest in cancers with particular PI3K pathway changes. Patients should not start aspirin without medical advice.
Key evidence
- Lieu C, Kennedy EB, Bergsland E, et al. Duration of oxaliplatin-containing adjuvant therapy for stage III colon cancer: ASCO clinical practice guideline. J Clin Oncol. 2019;37(16):1436-1447. doi:10.1200/JCO.19.00281
- eviQ. Colorectal adjuvant FOLFOX6 (modified) (fluorouracil, leucovorin, oxaliplatin). Cancer Institute NSW. Accessed June 23, 2026. https://www.eviq.org.au/medical-oncology/colorectal/adjuvant-and-neoadjuvant/637-colorectal-adjuvant-folfox6-modified-fluoro
- André T, Boni C, Mounedji-Boudiaf L, et al. Oxaliplatin, fluorouracil, and leucovorin as adjuvant treatment for colon cancer. N Engl J Med. 2004;350(23):2343-2351. doi:10.1056/NEJMoa032709
- André T, de Gramont A, Vernerey D, et al. Adjuvant fluorouracil, leucovorin, and oxaliplatin in stage II to III colon cancer: updated 10-year survival and outcomes according to BRAF mutation and mismatch repair status of the MOSAIC study. J Clin Oncol. 2015;33(35):4176-4187. doi:10.1200/JCO.2015.63.4238
- Courneya KS, Vardy JL, O’Callaghan CJ, et al. Structured exercise after adjuvant chemotherapy for colon cancer. N Engl J Med. 2025;393(1):13-25. doi:10.1056/NEJMoa2502760
- Martling A, Hed Myrberg I, Nilbert M, et al; ALASCCA Study Group. Low-dose aspirin for PI3K-altered localized colorectal cancer. N Engl J Med. 2025;393(11):1051-1064. doi:10.1056/NEJMoa2504650
Frequently asked questions (FAQs)
- Should Every Patient With Colon Cancer Take Aspirin?
No.
The strongest evidence applies to patients whose cancers have particular genetic changes involving the PI3K pathway.
Aspirin can also cause bleeding and may interact with other medicines.
Do not begin aspirin without discussing the potential benefits and risks with your oncologist.
- How Much Exercise Was Performed in the CHALLENGE Study?
The program aimed to gradually increase aerobic activity.
For many patients, the initial target was roughly equivalent to three or four brisk walks lasting 45–60 minutes each week.
However, the exercise was personalised according to the patient’s health and abilities, with regular professional support.
- Can Exercise Replace Chemotherapy?
No.
Exercise complements surgery and chemotherapy.
It does not replace standard cancer treatment.
- If My Scans Are Clear After Chemotherapy, Am I Cured?
Clear scans mean that no cancer can currently be seen.
Many patients with stage III colon cancer remain cancer-free permanently.
However, scans cannot guarantee immediately that the cancer will never return.
That is why follow-up appointments, blood tests, colonoscopies and scans remain important.
Dr Dilanka De Silva
MBBS, MRCP(UK), MRCP(UK SCE Oncology), FRACP, PhD
Medical Oncologist & Cancer Genetics Physician
Memorial Sloan Kettering Cancer Center Fellow (New York, USA)