Malignant gastroparesis: pathogenesis and management of an underrecognized disorder.
Gastroparesis is a disorder of the stomach caused by delayed gastric emptying in the absence of mechanical obstruction. Symptoms of gastroparesis include nausea, vomiting, early satiety, bloating, and abdominal discomfort. Gastroparesis has been described as a complication of several malignancies, including gastric, pancreatic, gallbladder, esophageal, and lung cancers, as well as leiomyosarcoma. The prevalence of malignant gastroparesis (MG) is unknown, and this entity is widely underrecognized and undertreated. Diabetes mellitus is the most common identifiable cause of benign gastroparesis, ie, gastroparesis occurring in the absence of an underlying malignant pathology. In the setting of malignancy, gastroparesis may result from the cancer itself or may be a complication of its treatment with such modalities as surgery, radiation therapy, or chemotherapy. Coexisting conditions, including diabetes, hypothyroidism, and neurologic diseases, may further exacerbate MG. The pathogenesis of MG is not clearly understood at present. However, mechanisms suggested in the literature include postvagotomy syndrome, malignant infiltration of the autonomic nervous system, and paraneoplastic dysmotility with autoantibody-mediated destruction of the enteric nervous system (the interstitial cells of Cajal, also called the intrinsic pacemaker of the gastrointestinal tract, or the myenteric plexus). Appropriate treatment of MG may help to avoid serious consequences, such as cancer cachexia, intolerance of oral anticancer agents, dehydration, and hospitalization. In this article, we will describe our institutional experience with MG and will provide a concise review of the literature. Guidelines for management will be suggested.