B107: Evaluation of  Hyponatraemia in Lung cancer patients: a U.K. teaching hospital  experience

ANKIT JAIN1,MARIAM JAFRI1,SALMA ALAM1,SOPHIE MASCALL1,RHIAN THOMAS1,JAMES KENDRICK1,JOYCE THOMPSON1

1Birmingham Heartlands Hospital, Birmingham, UK

Presenting date: Tuesday 3 November
Presenting time: 12.20-13.10

Background

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.

Method

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.

Results

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.

Conclusion

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.