Is Eating Fiber After Colorectal Cancer Diagnosis Associated with Lower Death Risk?

JAMA Oncology


Media advisory: To contact corresponding author Andrew T. Chan, M.D., M.P.H., email to Katie Marquedant at The full study is available on the For The Media website.

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Bottom Line: Eating more fiber was associated with a lower risk of death overall and from colorectal cancer in patients with non-metastatic colorectal cancer.

Why The Research Is Interesting: Colorectal cancer is common and the number of people living with treated disease is estimated to grow with advances in diagnosis and treatment. Many cancer survivors look for self-care strategies, especially advice on what to eat. Fiber intake is thought to be protective against colorectal cancer. But whether fiber intake is associated with recurrent colorectal cancer and survival in patients already diagnosed and treated has not been examined.

Who: 1,575 health professionals with non-metastatic (stages 1 to 3) colorectal cancer who provided detailed diet information on food questionnaires.

When: Fiber consumption was measured beginning in the 1980s; deaths were measured until 2012; the study was conducted from December 2016 to August 2017

What (Study Measures): Consumption of total fiber, different sources of fiber and whole grains from six months to four years after participants’ colorectal cancer diagnosis (exposures); deaths from colorectal cancer specifically and any cause (outcomes).

How (Study Design): This is an observational study. In observational studies, researchers observe exposures and outcomes for patients as they occur naturally in clinical care or real life. Because researchers are not intervening for purposes of the study they cannot control natural differences that could explain study findings so they cannot prove a cause-and-effect relationship.

Authors: Andrew T. Chan, M.D., M.P.H., of Massachusetts General Hospital and Harvard Medical School, Boston, and coauthors

Results:  During a median eight-year follow-up, a higher intake of fiber and whole grains after diagnosis of non-metastatic colorectal cancer cancer was associated with a lower risk of death from that disease and other causes. Survival improved for patients who increased their fiber intake after diagnosis compared to those who did not.

Study Limitations: Information about fiber intake and sources was self-reported without adjustment for measurement error. Detailed treatment data for the patients were largely unavailable.

Study Conclusions: “Higher fiber intake after the diagnosis of non-metastatic CRC [colorectal cancer] is associated with lower CRC-specific and overall mortality. Increasing fiber consumption after diagnosis may confer additional benefits to patients with CRC.”

Featured Image:

What The Image Shows: The image illustrates that overall and colorectal-cancer specific death appears to decline as total fiber intake increases after diagnosis.


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Editor’s Note: The article contains conflict of interest and funding/support disclosures. Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.

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