Aspirin Given After Colorectal Cancer Diagnosis Still Useful

Damian McNamara

October 19, 2017

ORLANDO — Daily low-dose aspirin started after a diagnosis of colorectal cancer might extend survival, according to one small study, which also confirms the preventive effects of the regimen.

"I absolutely was surprised by the findings," said Heidar Albandar, MD, a third-year internal medicine resident at Wright State University in Dayton, Ohio, here at the World Congress of Gastroenterology.

"I had always heard that aspirin was something that supposedly reduced the incidence of colorectal cancer," but some research out there also suggested that "it reduced mortality in patients started on aspirin after they were diagnosed," he told Medscape Medical News. "That really intrigued me because there are not a lot of data on that."

To examine the issue, Dr Albandar and his colleagues assessed the records of 174 veterans diagnosed with colorectal carcinoma from 1996 to 2014 — 91 who used aspirin and 83 who never used aspirin. About 98% of the patients were men, and about 90% were white.

Of the aspirin users, 69 patients started the therapy before their diagnosis and 22 started after their diagnosis.

The researchers collected information on the timing and duration of aspirin use, family history of cancer, demographic characteristics, stage of tumor, and time between diagnosis and death.

Median age at diagnosis was significantly older in aspirin users than in nonusers (71 vs 66 years; P = .001). And the proportion of patients diagnosed with stage III or IV cancer was lower in aspirin users than in nonusers (37.4% vs 56.6%; P = .011).

Median survival was about 20 months longer in aspirin users than in nonusers (987 vs 389 days; P = .002), regardless of whether aspirin was started before or after diagnosis.

In addition, "we found that the veterans who started aspirin before their diagnosis of colorectal cancer had reduced mortality or were being diagnosed with less severe forms of colorectal cancer," Dr Albandar reported. "They just did better."

Among aspirin users, veterans who initiated the therapy after their cancer diagnosis survived more than 1 year longer than those who were already taking aspirin at the time of their diagnosis, although the finding was not significant (1308 vs 921 days; P = .22).

Small Study, Select Group of Patients

The researchers "postulate that the development of more advanced malignancies in nonaspirin users may explain the mortality difference," said Jordan Karlitz, MD, from Tulane University in New Orleans.

However, "I have some issues with the study," he told Medscape Medical News. The researchers did not appear to control for other risk factors, such as comorbidities that could have affected survival. In addition, the research was retrospective and the study population, because they were veterans, was mostly male.

"The findings are interesting, but it's a small study of a select group of patients," said Dr Karlitz.

Dr Albandar agrees, and said it would be great to see these findings replicated in a larger, prospective clinical trial with nonveterans and more females.

Dr Albandar and Dr Karlitz have disclosed no relevant financial relationships.

World Congress of Gastroenterology 2017: Poster 102. Presented October 15, 2017.

Follow Medscape Gastroenterology on Twitter @MedscapeGastro and Damian McNamara @MedReporter

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