Histamine Type 2 Receptor Antagonists as Adjuvant Treatment for Resected Colorectal Cancer

Abstract

Colorectal cancer is the third most commonly diagnosed cancer in the world. Surgical resection is the main treatment strategy for colorectal cancer; however, chances of postsurgical relapse exist because of the undetected spread of cancer cells from the primary tumor to other tissues. In general, metastatic colorectal cancer is not curable. Therefore, adjuvant therapies that target remaining cancer cells are administered around the time of surgery to improve patient outcomes. H2RAs, including ranitidine and cimetidine, bind to cognate H2 receptors and block the action of histamine. H2RAs block H2 receptors that also are present on other cells types, mediating processes that have been investigated for their anticancer effects. Histamine acts as a growth factor for some gastrointestinal cancer cell lines, and inhibition of histamine activity through H2RAs has been shown to reduce colon cancer cell proliferation. H2RAs also have immunologic effects that collectively act to increase immune function. In addition, cimetidine has been shown to inhibit adhesion of metastatic cancer cells to healthy endothelial cells in a dosedependent manner. Therefore, H2RAs, particularly cimetidine, may be suitable for use as adjuvant therapies delivered around the time of surgery to simultaneously stimulate patients’ immune function, reduce cancer cell proliferation and spread, and potentially improve patients’ outcomes. A systematic review of the effect of H2RA use as an adjuvant therapy for the treatment of colorectal cancer was warranted. As nurses play vital roles in the care of patients undergoing treatment for cancer, maintaining up-to-date knowledge of available therapies is beneficial for providing comprehensive patient care.