Columbus, OH—So-called cancer fog might not be related only to actual chemo-immunotherapy treatment of the disease, according to a new study.

A report in the Journal of Cancer Survivorship suggests that acid-reflux medications recommended to ease digestive issues during cancer treatment might impair breast cancer patients’ memory and concentration.

Ohio State University–led researchers point out that proton-pump inhibitors (PPIs) are used in cancer patients to manage treatment-related gastrointestinal symptoms and to prevent damage to the gastric mucosal lining during treatment.

Yet, the researchers write, PPIs might contribute to cognitive problems. To test that, they compared PPI users and nonusers in three studies:
• In Study 1, breast cancer survivors , stages 0-IIIC, 36 out of 209 using PPIs rated their cognitive function on the Kohli scale prior to cancer treatment, as well as 1 and 2 years later.
• In Study 2, 31 used PPIs out of 200 participants, who were stages 0-IIIa and 11 months post-treatment. They rated their cognitive function on the Kohli scale and BCPT checklist at three visits over a 6-month period.
• In Study 3, 21 used PPIs out of 142 participants using PPIs. The participants, stages I-IIIa and 4 years post-treatment, rated their cognitive function on the Kohli scale, BCPT checklist, and Functional Assessment of Cancer Therapy cognitive scale (FACT-cog).

Results indicated that, in Study 1, PPI users reported more severe concentration problems (P = .039) but not memory problems (P = .17) than nonusers. In Study 2, PPI users reported more severe concentration problems (P = .022) than nonusers, but not memory problems or symptoms on the BCPT (PS = .11), while in Study 3, PPI users reported more severe memory problems (P = .002), poorer overall cognitive function (P = .006), lower quality of life related to cognitive problems (P = .005), greater perceived cognitive impairment (P = .013), and poorer cognitive abilities (P = .046), but not more severe concentration problems (P = .16), compared with nonusers.

“PPI use may impair breast cancer survivors’ memory, concentration, and quality of life,” the authors concluded.

“The severity of the cognitive problems reported by PPI users in this study was comparable to what patients undergoing chemotherapy had reported in a large observational study,” explained lead author Annelise Madison, a graduate student in clinical psychology at Ohio State.

“PPI non-users also reported problems, but were definitely getting better. Based on what we’re seeing, we don’t know if PPI users might not be able to fully recover cognitively after chemotherapy. It’s an area for further investigation.”

“The fact that this study found similar effects across three different sets of patients who are at different stages of cancer survivorship gives some weight to what we’re seeing,” added senior author Janice Kiecolt-Glaser, PhD, professor of psychiatry and psychology and director of the Institute for Behavioral Medicine Research at Ohio State. “Had it been in only a single study, it could have been a chance effect.”

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