Achlorhydria and cancer
Achlorhydria is a medical condition characterized by the absence of acid secretion in the stomach, resulting from the atrophy of parietal cells or the inactivation of enzymes responsible for acid production. This condition can increase the risk of gastric cancer, as studies show that approximately 60% of individuals with gastric cancer also have achlorhydria, compared to only 20% of healthy individuals. The link between achlorhydria and cancer is primarily due to chronic inflammation from untreated Helicobacter pylori infections, which can lead to atrophic changes in the stomach lining and the development of carcinogenic bacteria that synthesize harmful chemicals from dietary nitrates.
Patients with autoimmune diseases may also be at higher risk for developing achlorhydria. While the condition itself does not manifest symptoms, it can lead to deficiencies in vital nutrients like vitamin B12 and calcium, and may result in diarrhea due to bacterial overgrowth. Diagnosis typically involves measuring stomach acidity after stimulation with pentagastrin, and treatment focuses on addressing the underlying causes, including supplementing necessary vitamins and minerals. Understanding achlorhydria is crucial as it not only sheds light on potential health risks but also highlights the importance of addressing gastrointestinal health concerns to prevent serious complications.
On this Page
Subject Terms
Achlorhydria and cancer
ALSO KNOWN AS: Profound hypochlorhydria
RELATED CONDITIONS:Helicobacter pylori infection, chronic atrophic gastritis, gastric adenocarcinoma, gastric carcinoid
DEFINITION: Achlorhydria is the absence of acid secretion by the stomach caused by either atrophy of the acid-producing parietal cells or direct inactivation of the proton-pumping enzyme in parietal cells responsible for acid secretion.
Risk factors: The risk of achlorhydria increases with age and with long-term, untreated infection with the bacteria Helicobacter pylori. Patients with autoimmune conditions are also at increased risk. The condition has no predilection for sex or race.
Etiology and the disease process: Chronic inflammation of the stomach in response to untreated H. pylori infection lasting many years leads to the atrophy of stomach cells and a corresponding loss of acid-secreting capacity. Some patients may be more predisposed to achlorhydria in the presence of H. pylori because they respond to the infection by producing a specific inflammatory agent that is also a potent proton pump inhibitor. Autoimmune disease can also produce achlorhydria if the body makes antibodies that inactivate parietal cell proteins.
Achlorhydria is associated with the development of malignant cancer of the stomach. Approximately 60 percent of patients with gastric cancer have achlorhydria compared with 20 percent of healthy individuals. Acid normally acts as a disinfectant to prevent overgrowth of harmful bacteria; achlorhydria contributes to cancer development because the bacteria synthesize carcinogenic chemicals from nitrates present in food.
Achlorhydria is also associated with the formation of gastric carcinoid tumors. If acid output by the stomach is disrupted, the body overproduces the hormone gastrin, which stimulates overgrowth of enterochromaffin-like (ECL) cells in the stomach. This overgrowth may progress to carcinoid formation.
Incidence: Gastric carcinoids constitute 0.5 percent of gastric cancers. They are typically associated with autoimmune conditions and have a low risk of malignancy.
Symptoms: Achlorhydria itself causes no symptomssymptoms are secondary to the absence of acid. Lack of acid can cause vitamin B12 or calcium deficiency. Diarrhea may occur because of the overgrowth of bacteria.
Screening and diagnosis: Diagnosis is made by measuring the acidity of a stomach fluid sample after an intravenous injection of pentagastrin, which stimulates acid secretion in normal patients. Acidity will not increase in the stomach fluid of achlorhydric patients.
Treatment and therapy: Treatment focuses on addressing the underlying condition causing achlorhydria. Because vitamin B12 and calcium absorption are decreased, supplementation or injections of B12 may be necessary. Other required supplements may include iron, calcium, and vitamin D.
Prognosis, prevention, and outcomes: Restoration of normal acid production depends on prognosis and treatment for the underlying condition responsible for achlorhydria. For example, if other medications are determined to be causing achlorhydria, these may be curtailed. One example is proton pump inhibitors (PPIs). These are types of drugs designed to lessen the production of stomach acid. Prolonged usage of PPIs are believed to be a cause of achlorhydria.
Bibliography
D'Annibale, Annibale, Vito Pende, and Igor Monsellato. Gastric Cancer: From Staging to Surgical Treatment, Procedures, Complications, and Oncological Results. New York, Nova Science, 2012.
Gillson, Sharon. "An Overview of Achlorhydria." Verywell Health, 9 May 2024, www.verywellhealth.com/achlorhydria-1742373. Accessed 13 June 2024.
Gore, Richard M. Gastric Cancer. Cambridge, Cambridge UP, 2010.
Mattarelli, Paola, et al. "Occurrence of Bifidobacteriaceae in Human Hypochlorhydria Stomach." Microbial Ecology in Health and Disease, vol. 25, 20 Aug 2014, www.academia.edu/90197231/Occurrence‗of‗Bifidobacteriaceae‗in‗human‗hypochlorhydria‗stomach. Accessed 13 June 2024.
Rawish, Fatima, and Muhammad Aziz. “Achlorhydria.” StatPearls, 14 Aug. 2023, www.ncbi.nlm.nih.gov/books/NBK507793. Accessed 13 June 2024.
Singh Bhullar, Jasneet. Gastric Cancer: Risk Factors, Treatment and Clinical Outcomes. New York, Nova Science, 2014.
Yeh, Yi-Chun, et al. “H. pylori CagL-Y58/E59 prime higher integrin α5β1 in adverse pH condition to enhance hypochlorhydria vicious cycle for gastric carcinogenesis.” PLoS one, 29 Aug. 2013, journals.plos.org/plosone/article?id=10.1371/journal.pone.0072735. Accessed 13 June 2024.
Zaki, Muhammad, et al. "H. pylori Acutely Inhibits Gastric Secretion by Activating CGRP Sensory Neurons Coupled to Stimulation of Somatostatin and Inhibition of Histamine Secretion."American Journal of Physiology: Gastrointestinal and Liver Physiology, 15 Apr. 2013, doi.org/10.1152/ajpgi.00187.2012. Accessed 13 June 2024.
Zhou, Xiaoying, et al. “Decreased miR-204 in H. pylori-Associated Gastric Cancer Promotes Cancer Cell Proliferation and Invasion by Targeting SOX4” PloS one, 1 Jul. 2014, journals.plos.org/plosone/article?id=10.1371/journal.pone.0101457. Acessed 13 June 2024