Who this is for
Aspirin for bowel cancer recurrence is an important new area of research for patients who have completed surgery and chemotherapy for colon cancer or rectal cancer.
this article is for patients who have been diagnosed with colon cancer or rectal cancer and have completed surgery and chemotherapy, particularly those who have undergone genomic testing of their tumour.
It may also be helpful for patients seeking a second opinion regarding colorectal cancer in Melbourne, Australia, as well as those in Sri Lanka, the Maldives, Indonesia, and the Philippines.
Clinical Observation
A 61-year-old man who previously smoked receives a diagnosis of stage III colon cancer.
He undergoes surgery, and the pathology report shows that 4 out of 16 lymph nodes contain cancer. He completes six months of chemotherapy, and his follow-up CT scans show no evidence of cancer.
At his next appointment, he asks a question many patients ask:
“Doctor, I’ve done the surgery. I’ve done the chemotherapy. Is there anything else I can do to reduce the chance of this cancer coming back?”
Until recently, the answer was often “not really.”
However, a new study called ALASCCA suggests that for a specific group of patients, a simple aspirin tablet may significantly reduce the risk of recurrence.
The study showed benefit only in cancers carrying specific mutations within the PI3K pathway.
Why this matters
Historically, doctors mainly used molecular testing in patients with metastatic bowel cancer because the results helped guide treatment choices.
Increasingly, however, we are learning that genomic sequencing may also provide valuable information for patients with earlier-stage disease.
The ALASCCA study is one of the first large randomised studies to show that a molecular alteration can identify patients who benefit from a simple and inexpensive treatment after completing standard therapy.
Aspirin for bowel cancer recurrence: What was the ALASCCA trial?
ALASCCA was a randomised phase III study conducted across Scandinavian countries.
The study enrolled more than 600 patients with stage II and stage III colorectal cancer whose tumours contained alterations within the PI3K pathway, including:
- PIK3CA mutations
- PIK3R1 mutations
- PTEN alterations
Patients had already completed standard treatment.
Researchers randomly assigned patients to receive either:
- Aspirin 160 mg daily for three years
or - Placebo
The aim was simple:
Could aspirin reduce the risk of the cancer returning?
The answer appears to be yes.
Key results
- Aspirin reduced the chance of bowel cancer coming back in selected patients.
In patients with PIK3CA hotspot mutations, recurrence at 3 years was 7% with aspirin compared with 14.1% with placebo. - Patients with other PI3K pathway changes also appeared to benefit.
In this group, recurrence at 3 years was 7% with aspirin compared with 16.8% with placebo. - More patients remained alive and cancer-free with aspirin.
In the PIK3CA hotspot group, 3-year disease-free survival was 5% with aspirin compared with 81.4% with placebo. - Aspirin was not risk-free.
Severe adverse events occurred in 8% of patients taking aspirin compared with 11.6% of patients taking placebo. - The benefit was linked to tumour genetics.
This was not a study showing that every patient with bowel cancer should take aspirin. The benefit was seen in patients whose cancers had specific PI3K pathway changes.
In the PIK3CA-mutated group, the risk of recurrence was reduced by approximately 50%.
Importantly, the benefit appeared durable throughout follow-up.
Early overall survival results also favour aspirin, although longer follow-up is still required before definitive conclusions regarding overall survival can be made.
The Most Important Message
This is the key message many headlines miss.
The study did not show benefit across all bowel cancers.
It was seen in patients whose tumours carried specific PI3K pathway changes.
In simple terms, this study does not mean that every patient with colon cancer or rectal cancer should start aspirin.
It means that tumour gene testing may help identify which patients are more likely to benefit.
Without genomic testing, doctors would not know which patients are most likely to benefit.
That is why molecular testing is becoming increasingly important, even for some patients whose cancer has not spread to other organs..
What this means for you
If you have recently been diagnosed with stage II or stage III colon cancer or rectal cancer, it may be worth asking your oncologist whether your tumour has had gene testing.
This testing may show whether the cancer has a PIK3CA mutation or another change in the PI3K pathway.
For some patients with these tumour changes, aspirin may become a simple and relatively inexpensive way to help reduce the chance of the cancer coming back after surgery and chemotherapy.
However, aspirin is not suitable for everyone.
It can increase the risk of stomach irritation and bleeding, so the decision should always be made with your treating doctor.
The ALASCCA study shows something important.
Sometimes, progress in cancer care does not come from a new expensive drug.
Instead, it comes from using a familiar treatment in the right patient, at the right time.
Key takeaways
- Simple treatments can still make a big difference
Aspirin is familiar and widely available, but in the right molecular subgroup, it may reduce the risk of bowel cancer recurrence.
- Genomic testing is becoming more important
Tumour gene testing may help identify patients who could benefit from additional treatment strategies after surgery and chemotherapy.
- Not all bowel cancers are the same
The benefit was largely confined to cancers carrying PI3K pathway alterations such as PIK3CA mutations. This is a precision oncology story, not a one-size-fits-all story.
References
- Martling A, Myrberg IH, 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
- Martling A, Lindberg J, Myrberg IH, et al. Low-dose aspirin to reduce recurrence rate in colorectal cancer patients with PI3K pathway alterations: 3-year results from a randomized placebo-controlled trial. J Clin Oncol. 2025;43(4_suppl). doi:10.1200/JCO.2025.43.4_suppl.LBA125
- National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: Rectal Cancer. Version 2.2026. National Comprehensive Cancer Network; 2026. Accessed June 13, 2026.
- National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: Colon Cancer. Version 2.2026. National Comprehensive Cancer Network; 2026. Accessed June 13, 2026.
Frequently asked questions (FAQs)
No.
The benefit observed in ALASCCA was seen in patients whose tumours carried specific PI3K pathway alterations. Aspirin should not be started without discussing the risks and benefits with your treating doctor.
- How do I know whether my tumour has a PIK3CA mutation?
This can only be determined through molecular testing or genomic sequencing of the tumour tissue.
- Does this apply to both colon cancer and rectal cancer?
Yes. The study included patients with both colon cancer and rectal cancer.
No.
Patients in ALASCCA still received standard surgery and chemotherapy when indicated. Aspirin was evaluated as an additional strategy after standard treatment.
Overall, aspirin for bowel cancer recurrence is not a treatment for everyone, but it may become an important discussion for selected patients whose tumours have PI3K pathway changes.
Final thoughts
One of the most exciting changes in modern cancer care is that we are learning which treatments work best for which patients.
The ALASCCA study is a good example of this.
It reminds us that progress in cancer care is not always about expensive new drugs or complex technology.
Sometimes, it is about finding the right patient for a treatment that has been available for many years.
For patients whose bowel cancer has a PIK3CA mutation or another relevant PI3K pathway change, aspirin may become an important option to discuss after surgery and chemotherapy.
However, aspirin is not suitable for everyone.
The decision should always be made with the treating oncology team, taking into account the tumour gene testing results, bleeding risk, other medications and overall health.
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)