Serum sodium levels in the lower end of the normal range are associated with inferior outcomes in patients with metastatic renal cell carcinoma (mRCC) treated with tyrosine kinase inhibitors (TKIs) in the first-line setting, according to research published in Frontiers in Oncology.
Researchers found that patients with serum sodium levels of 135-139 mEq/L had inferior progression-free survival (PFS) and overall survival (OS), when compared with patients who had serum sodium levels of 140-145 mEq/L.
The study included 317 patients with mRCC who all had serum sodium concentrations within the normal range (135-145 mEq/L). The patients had a median age of 67 (range, 36-89) years, 73.1% were men, and 86.7% had clear cell mRCC. The TKIs patients received were sunitinib (54.9%), pazopanib (34.7%), and cabozantinib (10.4%).
The researchers compared patients with higher sodium levels (≥140 mEq/L) and lower sodium levels (<140 mEq/L) at baseline and at the first assessment. The baseline measurement was done within 10 days of starting TKI treatment. The first assessment was done roughly 40 days after patients started sunitinib and 26 days after they started pazopanib or cabozantinib.
The median PFS was significantly longer in patients with higher baseline sodium levels than in those with lower baseline sodium levels — 16 months and 12 months, respectively (P <.01).
There was no significant difference in median OS for patients with higher baseline sodium levels and those with lower baseline sodium levels — 64 months and 46 months, respectively (P =.2).
However, both the median PFS and median OS were significantly longer in patients with higher sodium levels at the first assessment.
The median PFS was 15 months in patients with higher sodium levels at the first assessment and 12 months in patients with lower sodium levels at that point (P <.01). The median OS was 70 months and 41 months, respectively (P =.02).
“To the best of our knowledge, this is the first study to evaluate the effect of normal sodium levels on mRCC outcomes in patients receiving targeted therapy as first-line treatment,” the researchers wrote. “A lower, but within the [normal] range, sodium concentration … may be an important factor associated with poorer survival in RCC patients, suggesting its possible use as an additional prognostic variable aside from the well-known nomograms for risk stratification.”
Roviello G, Catalano M, De Giorgi U, et al. Prognostic value of normal sodium levels in patients with metastatic renal cell carcinoma receiving tyrosine kinase inhibitors. Front Oncol. Published online August 16, 2022. doi:10.3389/fonc.2022.918413