Serum Calcium Level at Diagnosis Can Predict Lethal Prostate Cancer Relapse

Abstract

Background/Objectives: The most important prognostic factors in curatively treated prostate cancer are T and N stage, histology, grade group and initial PSA. A recent study found that men with blood calcium levels at the high end of the normal range are over two-and-a-half times more likely to develop fatal prostate cancer than those with lower calcium levels. However, there is limited evidence regarding the prognostic value of calcium levels at the time of prostate cancer diagnosis. We aimed to determine whether a calcium level in the upper range of normal values has any prognostic value in curatively treated prostate cancer. Methods: We conducted a retrospective analysis of 84 consecutive patients with prostate cancer who underwent curative-intent radiotherapy-either as primary treatment or adjuvant therapy-using external beam radiotherapy with or without brachytherapy. We analyzed all pertinent prognostic factors that could potentially impact disease-free survival. Results: The study revealed that calcium levels at diagnosis significantly predict disease-free survival, whereas the initial PSA level did not hold prognostic significance-likely due to interference from benign prostatic hyperplasia. Conclusions: If our findings are validated, calcium levels at the time of prostate cancer diagnosis could be incorporated into future predictive and prognostic models.

Keywords: early intervention; follow-up; metastases; predictive factors; prognostic factors; prostate cancer; serum calcium; tumor markers.

Figure 1

Overall survival and disease-free survival projected at 10 years for all patients from our analysis.

Figure 2

Log-rank test to correlate disease-free survival and PSA; p-values do not fall below 0.05.

Figure 3

Log-rank test to establish if Ca at diagnosis is a prognostic factor for DFS. (Blue line represents the p value at different Ca cut-off values; red straight line represents conventional statistical significance, of 0.05).

Figure 4

DFS at 10 years of patients with a serum calcium level of more or less than 9.65 mg/dL.

Figure 5

Log-rank test to determine the prognostic value of alkaline phosphatase. (Blue line represents the p value at different AP cut-off values; red straight line represents conventional statistical significance, of 0.05.)