Hypocalcemia in cancer patients: An exploratory study

Calcium has several physiological functions and when it registers abnormal serum levels those functions may be impacted with potentially severe consequences. There is much research on hypercalcemia in cancer patients, but there are no recent studies on the prevalence of hypocalcemia in those patients. However, there has been an evolution in oncology, namely, new drugs that may directly or indirectly result in hypocalcemia. The primary aim was to explore the association of hypocalcemia with the diverse types of cancer. The secondary aim was to study the influence that hypocalcemia might have on survival.

Review of the records of patients ≥18 years old, with total calcium <2.0 mmol/L measured in 2013 in a cancer center.

Eight hundred twenty-nine patients were included. Four hundred thirty-nine (53%) were male. The median age was 63 years. The most frequent cancer diagnoses were hematological 196 (24%) and colorectal 111 (13%). Six hundred thirty-eight patients had measured serum albumin, with a median of 25.5 g/L (14-47). When corrected for albumin level, calcium was in the normal range in 210 (33%) cases. The median survival of patients with corrected calcium lower than normal was 479 days (95% confidence interval [CI]: 309-649) and that of patients with normal corrected calcium was 62 days (95% CI: 33-91), P < .001. In a multivariate analysis, age, primary cancer, and albumin were significantly associated with survival.

Hypocalcemia is associated with several types of cancer. A low calcium level is not by itself a factor of a poor prognosis since other factors seem to be more important.