B107: Evaluation of Hyponatraemia in Lung cancer patients: a U.K. teaching hospital experience
1Birmingham Heartlands Hospital, Birmingham, UK
Hyponatraemia, defined as serum Na of <135mEq/L, is the commonest electrolyte abnormality in oncology practice. We describe demographics, oncological management and response of hyponatraemia to oncological treatment modalities in hospitalised patients with lung cancer in a large teaching hospital.
We retrospectively analysed serum sodium levels in all lung cancer patients admitted to a West Midlands teaching hospital between 2007-2013. Data was collected on baseline demographics, histology, tumour stage and grade of hyponatraemia. Mild hyponatraemia was defined as a serum sodium between 130-135mEq/L, moderate 125-129mEq/L, and severe <124mEq/L.
182 (108 male; 74 female) patients with lung cancer and documented hyponatraemia were hospitalised between 2007-2013. Median age was 69.2 years (range 33-92 years). 119(65%) had mild, 58(32%) moderate and 5(3%) severe hyponatraemia. 74(40%) were adenocarcinomas , 58(32%) squamous, 43(24%) SCLC and 7(4%) had unspecified non-small cell lung cancer. 89(49%) had metastatic disease at diagnosis. 18/43 (42%) small cell, 14/58 (33%) squamous , 23/74 (31%) adenocarcinoma patients had moderate to severe hyponatraemia. 132(74%) of this cohort had active oncological treatment: 93(51%) chemotherapy, 25(14%) radiotherapy, 17(9%) surgery whilst 47(26%) had best-supportive care. 28(15%) had a biochemical response to their treatment, 11(39%) of these patients were adenocarcinomas, 10(36%) squamous carcinomas and 7(25%) SCLC.
Hyponatraemia in lung cancer patients is widely distributed in various age groups and histological subtypes. Among those admitted with hyponatraemia, severe cases (<124mEq/L) were rare. Higher rates of SIADH are seen in SCLC than in any other malignancy and our data confirmed that, proportionately, more SCLC patients had moderate - severe hyponatremia than non small cell lung cancer patients. Hyponatraemia does respond to active oncological treatment including chemotherapy, radiotherapy and surgery. Although historically, hyponatraemia is considered as a poor prognostic marker and significantly associated with shorter survival duration, this shouldn't preclude active oncological management. Further studies are needed to evaluate the prognostic value of hyponatraemia and it's treatment in cancer patients.