Is there any Potential Clinical Impact of Serum Phosphorus and Magnesium in Patients with Lung Cancer at First Diagnosis? A Multi-institutional Study

Background: The aim of the study was to determine whether the expression of baseline phosphorus (P) andmagnesium (Mg) levels were prognostic in terms of stage and overall survival (OS) in newly diagnosed non-smallcell lung cancer (NSCLC) and small cell lung cancer (SCLC) patients. Materials and
Methods: Retrospectively,130 patients were selected at the time of diagnosis oflung cancer (100 with NSCLC and 30 with SCLC), beforethe initialization of any chemo-radiotherapy. The median age was 67 (range 29-92). IA, IB, IIA, IIB, IIIA, IIIBand IV stages were present in 3, 4, 19, 6, 25, 8, and 65 patients, respectively. After centrifugation, the levels ofserum P and Mg were measured using the nephelometric method/ photometry and evaluated before any type oftreatment.
Results: Higher than normal levels of P were found in 127/130 patients, while only four patients hadelevated Mg serum values. In terms of Spearman test, higher P serum values correlated with either stage (rho=-0.334, p<0.001) or OS (rho=-0.212, p=0.016). Additionally, a significant negative correlation of Mg serum levelswas found with stage of disease (rho=-0.135, P=0.042). On multivariate cox-regression survival analysis, only stage(p<0.01), performance status (p<0.01) and P serum (p=0.045) showed a significant prognostic value.
Conclusions:Our study indicated that pre-treatment P serum levels in lung cancer patients are higher than the normal range.Moreover, P and Mg serum levels are predictive of stage of disease. Along with stage and performance status,the P serum levels had also a significant impact on survival. This information may be important for stratifyingpatients to specific treatment protocols or intensifying their therapies. However, larger series are now neededto confirm our results.