Paraneoplastic syndromes: A focus on pathophysiology and supportive care.

Purpose: This article aims to increase awareness of, outline pathophysiology for, and offer guidance on supportive care strategies for specific endocrine, neurological, and immunological syndromes associated with paraneoplastic syndromes (PNSs).

Summary: PNS refers to remote effects that cannot be attributed to the direct or invasive effects of a malignancy. These syndromes are considered clinically important because they may provide early recognition, diagnosis, and management of the malignancy in a timely manner. Many of their presenting symptoms such as ectopic Cushing's syndrome, hypercalcemia of malignancy (HCM), syndrome of inappropriate secretion of antidiuretic hormone (SIADH), neurological dysfunctions, and paraneoplastic autoimmune thrombocytopenia overlap with those of nonneoplastic disorders, yet their pathogenesis and responses to treatments differ. Management of ectopic Cushing's syndrome due to a PNS consists of treatment of the underlying malignancy and its comorbidities. Drug therapies may include ketoconazole, mitotane, metyrapone, somatostatin analogs, and dopamine agonists. Hypercalcemia may be classified into cases with parathyroid hormone (PTH)-dependent causes or PTH-independent causes such as HCM, in which osteoclast inhibitors may be deployed. Treatments of PNS-mediated SIADH include treatment of the underlying malignancy and strategies to increase serum sodium levels. Amifampridine is now considered the first-line agent for paraneoplastic Lambert-Eaton myasthenic syndrome, whereas steroids, intravenous immune globulin, thrombopoietin receptor agonists (eg, romiplostim, eltrombopag, and avatrombopag), fostamatinib, and rituximab may find their niche in treatment of PNS-mediated autoimmune thrombocytopenia.

Conclusion: Supportive care for PNSs lends opportunities to pharmacists to add quality, value, and safety.