Tumor-related dysmotility: Gastrointestinal dysmotility syndromes associated with tumors
Although symptoms referrable to disturbances in gastrointestinal motor function are frequently encountered in patients with neoplastic conditions, they are notoriously nonspecific and discrete disorders based on well- defined myoneural pathology are distinctly uncommon. This may reflect the current state of the diagnostic methods available for clinical use. The clinical impact of more sophisticated diagnostic tests has also been limited by both an imperfect relationship between symptoms and dysfunction and by a relatively poor ability of such tests to predict response to available therapies (3). Nevertheless, renewed interest in gastrointestinal motility, the availability of an assortment of diagnostic methodologies that provide a better evaluation of gut motor function, together with a greater understanding of the pathophysiology of such disorders should lead to increased collaboration between gastroenterologists and oncologists and to much needed progress in this area. In this review, we have attempted to focus primarily on the pathophysiology of dysmotility in relation to neoplastic conditions in the setting of a relatively restricted number of clearly defined clinical syndromes. Many of the best characterized conditions are uncommon; nevertheless, they provide excellent examples of how derangements of the neuromuscular apparatus of the gut can affect gastrointestinal motility (200). Furthermore, while not exceedingly common, it is imperative that physicians be aware of disturbances of gastrointestinal motility that should prompt an investigation for an underlying malignancy (paraneoplastic visceral neuropathy, carcinoma-induced achalasia, central nervous system tumors). Finally, a recognition of the more common causes of gastrointestinal dysmotility, including therapeutic agents (irradiation, antineoplastic agents), infections, and metabolic derangements, is imperative for those individuals who care for these patients. While a full description of the diagnostic approach to and therapy of these disorders is beyond the scope of this article, a number of excellent articles are available for review (3, 104, 186).