Impact of Chemotherapy on Hypercalcemia in Breast and Lung Cancer Patients

Introduction: Hypercalcemia is mainly caused by bone resorption due to either secretion of cytokinesincluding parathyroid hormone-related protein (PTHrP) or bone metastases. However, hypercalcemia may occurin patients with or without bone metastases. The present study aimed to describe the effect of chemotherapytreatment, regimens and doses on calcium levels among breast and lung cancer patients with hypercalcemia.
Methods: We carried a review of medical records of breast and lung cancer patients hospitalized in years2003 and 2009 at Penang General Hospital, a public tertiary care center in Penang Island, north of Malaysia.Patients with hypercalcemia (defined as a calcium level above 10.5 mg/dl) at the time of cancer diagnosis orduring cancer treatment had their medical history abstracted, including presence of metastasis, chemotherapytypes and doses, calcium levels throughout cancer treatment, and other co-morbidity. The mean calcium levelsat first hospitalization before chemotherapy were compared with calcium levels at the end of or at the latestchemotherapy treatment. Statistical analysis was conducted using the Chi-square test for categorical data,logistic regression test for categorical variables, and Spearman correlation test, linear regression and the pairedsample t tests for continuous data.
Results: Of a total 1,023 of breast cancer and 814 lung cancer patientsidentified, 292 had hypercalcemia at first hospitalization or during cancer treatment (174 breast and 118 lungcancer patients). About a quarter of these patients had advanced stage cancers: 26.4% had mild hypercalcemia(10.5-11.9 mg/dl), 55.5% had moderate (12-12.9 mg/dl), and 18.2% severe hypercalcemia (13-13.9; 14-16 mg/dl).Chemotherapy lowered calcium levels significantly both in breast and lung cancer patients with hypercalcemia;in particular with chemotherapy type 5-flurouracil+epirubicin+cyclophosphamide (FEC) for breast cancer, andgemcitabine+cisplatin in lung cancer.
Conclusion: Chemotherapy decreases calcium levels in breast and lungcancer cases with hypercalcemia at cancer diagnosis, probably by reducing PTHrP levels.