Hyponatraemia—SIADH in lung cancer diagnostic and treatment algorithms

Lung cancer, in particular small cell lung cancer (SCLC), is a very aggressive solid tumour with limited therapeutic options to date. The majority of patients present, at the time of diagnosis, with extensive disease patterns and reduced performance status. Hyponatraemia is a common finding in SCLC (25%) which can be assigned to a paraneoplastic syndrome termed syndrome of inappropriate ADH secretion (SIADH) in 60% of cases. Hyponatraemia may cause significant and even dramatic neurocognitive deficits, if not treated in an effective manner. Palliative chemo- or radiotherapy is restricted to patients with good performance status and therapeutic adherence. Acute or persistent hyponatraemia may interfere with such treatment options and compromise outcome. This review integrates new diagnostic and therapeutic guidelines to improve the understanding how and when to treat hyponatreamia in thoracic oncology patients Integrating early palliative care in lung cancer patients has a significant impact on prognosis. Correcting hyponatraemia in a supportive and risk stratified fashion may help to improve both prognosis and quality of life and should be a standard in modern palliative care for patients with lung cancer.