Aspirin Nearly Doubles Survival in GI Cancers

Liam Davenport

September 27, 2015

VIENNA — Low-dose daily aspirin almost doubles survival among patients with a range of gastrointestinal (GI) tract cancers, reveals an analysis of prescribing data from the Netherlands.

The finding comes from a retrospective study of almost 1400 GI cancer patients presented here at European Cancer Congress (ECC) 2015. The researchers found that among a subgroup of patients (8.3%) who took aspirin post-diagnosis, the 5-year overall survival was 75% among daily aspirin users vs just more than 40% in those who did not take the drug.

Most patients had cancer of the colon (48%); the next most common sites were the rectum (42.8%) and the esophagus (10.2%).

The data were presented by Martine Frouws, MD, from Leiden University Medical Centre, in the Netherlands.

Dr Martine Frouws

Having found benefits in patients with a range of different GI cancers and at all stages of the disease, the team is now conducting a randomized controlled trial to confirm the benefits of this low-cost, low-risk therapeutic option.

"Medical research is focusing more and more on personalized medicine, but many personalized treatments are expensive and only useful in small populations," Dr Frouws commented in a statement.

"We believe that our research shows quite the opposite -- it demonstrates the considerable benefit of a cheap, well-established, and easily obtainable drug in a larger group of patients, while still targeting the treatment to a specific individual."

Aspirin for Prevention and as an Adjunct

Aspirin is already well known for its ability to protect against colorectal cancer as well as other diseases. These new data "tell us that not only can aspirin prevent disease, but low-dose aspirin is important as an adjunct therapy for gastrointestinal cancers," said Nadir Arber, MD, head of the Integrated Cancer Prevention Center, Tel Aviv Sourasky Medical Center, Israel, in a statement.

"Aspirin may serve as the magic bullet because it can target and prevent ischemic heart disease, cancer, and Alzheimer's disease, the three major health catastrophes in the third millennium," he was quoted as saying in the release.

Adding a note of caution, he said: "The appropriate dosage and duration of aspirin use and risk-benefit ratios of aspirin use remain to be determined, but in the area of precision medicine, genetic information and blood and/or urinary biomarkers may help in tailoring treatment to those who will benefit most, while limiting adverse effects."

Analysis of Dispensing Data

Dr Frouws and colleagues examined 13,715 patients diagnosed with a GI cancer between 1998 and 2011, linking them to drug dispensing data from PHARMO, the Institute for Drug Outcomes Research, in Utrecht, the Netherlands, to obtain each separate prescription per patient.

In all, 30.5% of the patients used aspirin before their diagnosis, 8.3% started using the drug after their diagnosis, and 61.1% did not take aspirin at all. The patients typically took low-dose aspirin (80-100 mg).

The median follow-up time was 48.6 months; 28% of patients survived for at least 5 years.

The results reported here at the meeting show that overall survival at 5 years was 75% in the subgroup of patients who took aspirin post-diagnosis vs just 42% for those who did not take the drug.

Analyzing the result by type of GI cancer revealed that there was a substantial and significant benefit with daily low-dose aspirin for esophageal, stomach, colon, and rectal cancer.

There was also a borderline significant benefit for patients with hepatobiliary tract cancer who took aspirin. However, there was no benefit from low-dose aspirin for patients with pancreatic cancer.

Crucially, the significant survival benefits were seen in cancer patients at all stages, and the results held after adjusting for sex, age, stage of cancer, surgery, radiotherapy, chemotherapy, and other medical conditions or disorders.

The researchers believe that the beneficial effect of cancer is due to its antiplatelet effect, in that it may prevent circulating tumor cells (CTCs) from "hiding" inside the platelets that surround them. By inhibiting platelet function, aspirin exposes the CTCs to the immune system and, thus, leads to their elimination.

Summarizing, Dr Frouws told a press briefing: "Patients using aspirin after diagnosis of a gastrointestinal malignancy have a chance of survival twice as high compared to patients not using aspirin.

"If aspirin was to become a regular treatment for cancer, it's going to have a large effect on cancer survival and global health," she said.

Next Steps

Discussing the next steps for their research, Dr Frouws commented: "Now we would like to analyze tumor material from these patients to try and discover which ones would benefit from aspirin treatment. Through studying the characteristics of tumors in patients where aspirin was beneficial, we should be able to identify patients who could profit from such treatment in the future."

To those ends, a multicenter, randomized, placebo-controlled trial is under way in the Netherlands to examine the impact of aspirin 80 mg once daily on overall colon cancer survival in elderly patients. The team hopes to expand the trial to include further GI tract sites.

If the findings show a benefit from daily low-dose aspirin, Dr Frouws believes it could change the way clinicians look at the 100-year-old drug.

"Given that aspirin is a cheap, off-patent drug with relatively few side effects, this will have a great impact on healthcare systems as well as patients," she said.

The study received no outside funding. No significant financial relationships have been disclosed.

European Cancer Congress (ECC) 2015: Abstract 2306. Presented September 28, 2015.


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