Hyponatraemia is an abnormally low level of sodium in the blood. It can be caused by a range of factors, from an underlying medical condition to drinking too much water and diluting the blood. In people with mesothelioma, hyponatraemia can also be triggered by chemotherapy.
By analyzing the cases of 62 consecutive mesothelioma patients on chemotherapy, researchers with the Marche Polytechnic University in Ancona, Italy determined that those who developed hyponatraemia were less likely to have good outcomes. All patients received pemetrexed-based chemotherapy as a first-line treatment for their mesothelioma between 2003 and 2013. Twenty-nine of the mesothelioma patients went through chemotherapy a second time.
Dr. Rossana Berardi, the lead author on the newly-published report, writes, “The occurrence of hyponatraemia during first-line chemotherapy was significantly associated to a shorter median progression-free survival. Results were also similar in the subgroup receiving a second-line treatment.”
Patients whose serum sodium level dropped to less than 135 mEq/L (milliequivalents per liter) during treatment had a median survival of just 7.93 months. In contrast, patients whose sodium levels remained normal during chemotherapy lived a median of 13.48 months – a six-month survival advantage.
When the research team evaluated a multitude of factors that could potentially have an impact on mesothelioma survival times, including age, gender, smoking habit, asbestos exposure and overall health, only hyponatraemia was found to be an independent prognostic factor. In their article in Support Care for Cancer, the team concludes that, in addition to predicting overall survival, hyponatraemia levels could be useful for predicting response to chemotherapy; mesothelioma patients who developed the condition did not respond as well to treatment.
The Italian researchers say theirs is the first study to directly associate hyponatraemia with malignant pleural mesothelioma outcomes. Prognostic indicators are an important part of treatment planning for mesothelioma, an aggressive asbestos-linked cancer with no known cure.
Berardi, R, et al, “Hyponatraemia is a predictor of clinical outcomes for malignant pleural mesothelioma”, August 21, 2014, Support Care in Cancer, Epub ahead of print