Lessons learned: endoscopy with 96-hour ambulatory esophageal pH monitoring as a tool to avoid proton pump inhibitor use in cancer patients with refractory gastroesophageal reflux

The proton pump inhibitors (PPIs) are extensively prescribed for the empirical treatment of epigastric pain and heartburn in cancer patients. However, they carry the potential for drug interactions with antineoplastic agents during active cancer therapy, and osteopenia, opportunistic infections, adverse cardiovascular outcomes, and altered gut microbiome in long-term users in survivorship. Herein, we examined the use of endoscopy with esophageal 96-hour ambulatory pH monitoring in guiding clinicians in safely prescribing PPI in 21 such patients. We retrospectively studied patients with active cancer or in survivorship, presenting with PPI-refractory heartburn. All underwent an endoscopy with esophageal ambulatory pH monitoring performed "off" PPI therapy for 96 hours, following a "liberal diet" for the first 48, and a "restrictive diet" for the latter 48 hours. Acid exposure time (AET) ≥ 6% per 24 hours was defined as abnormal. For each patient, the average AET from the first 2 days was considered as baseline and was compared with that from the latter 2 days (on restrictive diet). We concluded that ambulatory 96-hour pH monitoring, identifies 48% of patients with normal AET, who may not need PPI. Esophageal pH monitoring on restrictive diet normalizes AET in 73% of patients, thereby allowing esophageal acid control to be achieved with diet alone.