Who this is for
Aspirin bowel cancer recurrence research is becoming important for patients who have completed surgery and chemotherapy and want to know whether anything else can reduce the chance of the cancer coming back.
This article is for people with stage III colon cancer or rectal cancer who has completed surgery and six months of chemotherapy and asks the question I hear almost every week:
“I’ve done everything you’ve asked me to do. Is there anything else I can do to reduce the chance of the cancer coming back?”
Until recently, the answer was usually limited to exercise, maintaining a healthy weight, avoiding smoking, and attending follow-up scans and colonoscopies.
Now, a new study suggests that for some patients, a simple aspirin tablet may reduce the risk of recurrence by about 50%.
The important detail is that the benefit appears to depend on the genetic makeup of the tumour.
Clinical Observation
A 56-year-old woman undergoes surgery for stage III colon cancer.
She completes six months of adjuvant chemotherapy.
Her scans show no evidence of cancer.
On paper, this was good news.
However, like many patients at this stage, she did not feel completely reassured.
The treatment is finished.
The chemotherapy is over.
But the fear remains.
“What else can I do?”
A few years ago, I would have focused on exercise, weight management, surveillance scans and symptom awareness.
Today, I would also want to know whether her tumour carries a PIK3CA mutation or another alteration within the PI3K pathway.
That information may now influence a prevention strategy after chemotherapy has finished.
Aspirin bowel cancer recurrence: What did the ALASCCA trial show?
What was studied?
Researchers investigated whether low-dose aspirin could reduce recurrence in patients whose colorectal cancers contained alterations in the PI3K pathway.
Study design
- Phase III randomised placebo-controlled trial.
- Conducted across Sweden, Denmark, Norway and Finland.
- 3,508 patients screened.
- 2,980 tumours successfully underwent genomic testing.
- Researchers randomly assigned 626 patients with PI3K pathway alterations to receive aspirin or placebo.
- Intervention: aspirin 160 mg daily for 3 years.
- Control: placebo.
Australia and the United States did not participate in this study.
Key results
- Aspirin reduced the chance of bowel cancer coming back in selected patients.
In patients with classical PIK3CA mutations, aspirin reduced the risk of recurrence by about 50%. (Hazard ratio: 0.49) - More patients remained cancer-free after aspirin.
After 3 years, 88.5% of patients taking aspirin were alive without the cancer coming back, compared with 81.4% of patients taking placebo. (Hazard ratio: 0.61) - The benefit was linked to tumour biology.
The benefit was seen in patients whose cancers had PIK3CA mutations or related PI3K pathway alterations. (Hazard ratio: 0.42) - This could be relevant to many bowel cancer patients.
PI3K pathway alterations are found in approximately 35–40% of colorectal cancers.
What does this study actually mean?
Three things stand out to me.
- Simple Interventions Can Still Be Powerful
Modern oncology often focuses on highly sophisticated treatments.
However, one of the most exciting recurrence-prevention studies in bowel cancer involves a medication that has existed for more than 100 years.
Importantly, the lesson is not that aspirin replaces chemotherapy.
Rather, the lesson is that simple interventions can still make a meaningful difference when used in the right patient.
- We Are Entering the Era of Genomics-Guided Prevention
Traditionally, genomic testing was mainly used in advanced or metastatic bowel cancer.
That is changing.
Increasingly, tumour genomic information is helping us understand recurrence risk, guide treatment decisions, and now identify possible prevention strategies after treatment.
This is one of the clearest examples of how tumour biology may influence decisions long after chemotherapy has finished.
- The Future Is Becoming More Personalised
Two patients with the same stage of bowel cancer may not have the same risk of recurrence.
More importantly, they may not benefit from the same prevention strategies.
This study suggests that the future of cancer care is not only about asking whether the cancer has been removed.
It is also about understanding the biology of that cancer and tailoring the next steps accordingly.
For some patients, that may include considering aspirin after treatment, but only if the tumour has the right genetic changes and only after discussion with the treating oncology team.
Overall, aspirin bowel cancer recurrence research suggests that prevention after treatment may become more personalised, especially when tumour genomic testing identifies PI3K pathway alterations.
Key takeaways
- Aspirin reduced recurrence risk by approximately 50% in patients whose tumours contained PIK3CA or related PI3K pathway alterations.
- Approximately 35–40% of colorectal cancers contain alterations within the PI3K pathway, making this relevant to a substantial number of patients.
- Tumour genomic sequencing is becoming increasingly important even in early-stage colon and rectal cancer, helping guide prognosis, treatment decisions and potentially recurrence-prevention strategies.
Key evidence
- 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
- Killock D. ALASCCA: an aspirin a day keeps colorectal cancer away. Nat Rev Clin Oncol. 2025;22:801. doi:10.1038/s41571-025-01082-2
- European Society for Medical Oncology. Low-dose adjuvant aspirin decreases incidence of recurrence among patients with resected PI3K-altered CRC. ESMO. Accessed June 8, 2026. https://www.esmo.org/oncology-news/low-dose-adjuvant-aspirin-decreases-incidence-of-recurrence-among-patients-with-resected-pi3k-altered-crc
Frequently asked questions (FAQs)
- Should everyone with bowel cancer take aspirin?
No.
The benefit demonstrated in ALASCCA was seen in patients whose tumours contained specific PI3K pathway alterations.
Aspirin can also cause bleeding and should only be considered after discussion with your treating team.
- Should my tumour be genetically tested?
Increasingly, yes.
Genomic testing is becoming an important part of understanding prognosis and identifying emerging treatment and prevention strategies.
- Does aspirin replace chemotherapy?
No.
Patients in ALASCCA received standard surgery and chemotherapy where appropriate.
Aspirin was an additional strategy rather than a replacement for established treatment.
- Does this apply to rectal cancer as well as colon cancer?
Potentially yes.
The study included colorectal cancer patients, although individual recommendations should always be discussed with your treating oncologist.
- Why this matters for patients in Melbourne, Sri Lanka, the Maldives, Indonesia and the Philippines
One of the most exciting developments in modern colorectal cancer care is that treatment decisions are increasingly based on the biology of the tumour rather than simply where a patient lives.
Whether you are receiving treatment in Melbourne or seeking a colorectal cancer second opinion from Sri Lanka, the Maldives, Indonesia or the Philippines, understanding the genomic profile of the tumour is becoming increasingly important.
The question is no longer simply:
“Has the cancer been removed?”
The next question is becoming:
“What does the biology of the tumour tell us about what to do next?”
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)