In the context of cancer, monitoring serum calcium levels is critical because certain cancers can cause hypercalcemia or hypocalcemia. Hypercalcemia, an elevated level of calcium in the blood, is more common and can be a paraneoplastic syndrome, indicating advanced disease or a relapse. Hypocalcemia, a lower than normal level of calcium, can also occur, often as a result of treatment or nutritional deficiencies.
