Hyponatraemia as a Marker of Inferior Outcomes in Small Cell Lung Cancer (SCLC)

ABSTRACT Introduction Small cell lung cancer (SCLC) represents approximately 15% of all lung cancer diagnoses and is reducing in incidence. Hyponatremia is a common and debilitating electrolyte disorder, frequently documented in SCLC. Its occurrence is typically attributed to paraneoplastic syndrome- induced syndrome of inappropriate antidiuretic hormone hypersecretion (SIADH). The influence of hyponatremia on the survival of patients with lung cancer remains poorly understood. Aim: The aim of this retrospective study is to investigate clinical features and the prognostic value of hyponatremia in an unselected Irish patient population with small cell lung cancer (SCLC) with limited disease (LD) and extensive disease (ED). Method The data of patients diagnosed with SCLC in Beaumont hospital over a 3-year period was analysed retrospectively. Patients were identified from analysis of all lung cancers biopsies via the pathology department databank. Data was collected from clinical notes on identified patients including clinical performance status, serum sodium values, disease stage, chemotherapy regimens and response, radiotherapy, palliative care input and survival. Results 48 patients (22 male, 26 female) with a median age 64 yrs (range 41-87yrs), 29.17%(n = 14) with limited stage were identified. The standard chemotherapy was carboplatin–etoposide. 7 patients received 2nd line treatment with irinotecan. 16.6% patients did not receive chemotherapy (n = 8) due to poor performance status. Hyponatraemia (plasma sodium [P-Na] Conclusions Hyponatraemia is a common occurrence in patients with SCLC, and one of the most frequent paraneoplastic syndromes noted. Profound hyponatremia is associated with significantly shorter observed median survival and should be considered in generating treatment in patients with SCLC. Disclosure All authors have declared no conflicts of interest.