Carcinoid syndrome: update on the pathophysiology and treatment

Approximately 30-40% of patients with well-differentiated neuroendocrine tumors present with carcinoid syndrome, which is a paraneoplastic syndrome associated with the secretion of several humoral factors. Carcinoid syndrome significantly and negatively affects patients' quality of life; increases costs compared with the costs of nonfunctioning neuroendocrine tumors; and results in changes in patients' lifestyle, such as diet, work, physical activity and social life. For several decades, patients with neuroendocrine tumors and carcinoid syndrome have been treated with somatostatin analogues as the first-line treatment. While these agents provide significant relief from carcinoid syndrome symptoms, there is inevitable clinical progression, and new therapeutic interventions are needed. More than 40 substances have been identified as being potentially related to carcinoid syndrome; however, their individual contributions in triggering different carcinoid symptoms or complications, such as carcinoid heart disease, remain unclear. These substances include serotonin (5-HT), which appears to be the primary marker associated with the syndrome, as well as histamine, kallikrein, prostaglandins, and tachykinins. Given the complexity involving the origin, diagnosis and management of patients with carcinoid syndrome, we have undertaken a comprehensive review to update information about the pathophysiology, diagnostic tools and treatment sequence of this syndrome, which currently comprises a multidisciplinary approach.

Síndrome carcinoide y compromiso valvular cardíaco / Carcinoid syndrome anf heart valve involvemen

El carcinoide es un tumor neuroendocrino raro que se origina típicamente en el tracto gastrointestinal y que puede resultar en un amplio espectro de síntomas mediado por sustancias vasoactivas. La enfermedad carcinoide con compromiso cardíaco es caracterizada por el depósito de tejido fibroso en forma de placas, afectando más frecuentemente las válvulas cardíacas derechas y el endocardio. El compromiso valvular izquierdo ocurre en menos del 10 por ciento de los casos y es casi siempre asociado a un cortocircuito de derecha a izquierda o a un carcinoide bronquial primario. Los pacientes con falla cardíaca derecha sintomáticos tienen limitadas opciones terapéuticas diferentes a la cirugía cardíaca. El reemplazo valvular cardíaco es el único tratamiento efectivo para la enfermedad valvular carcinoide y debiese ser considerada en pacientes sintomáticos, en los cuales la enfermedad metastásica y los síntomas del síndrome carcinoide se encuentran bien controlados. Por estos motivos, se recomienda un enfoque multidisciplinario en un centro de experiencia para este tipo de pacientes. El presente artículo es una revisión actualizada de la literatura al respecto, tratando de clarificar las principales dudas con respecto al manejo de estos pacientes.

Carcinoid is a rare neuroendocrine tumor typically originating in the gastrointestinal tract and which may result in a broad spectrum of symptoms mediated by vasoactive substances. Carcinoid heart disease is characterized by plaque-like deposits of fibrous tissue, most frequently affecting the right heart valves and endocardium. Left-sided valve disease occurs in less than 10 percent of patients with cardiac involvement and is almost always associated with an atrial right-to-left shunt or a primary bronchial carcinoid. Patients with symptomatic right heart failure have limited therapeutic options other than cardiac surgery. Cardiac valve replacement is the only effective treatment for carcinoid heart disease and should be considered for symptomatic patients whose metastatic carcinoid disease and symptoms of carcinoid syndrome are well controlled. A multidisciplinary approach at an experienced center is recommended for the care of these patients.