Severe and prolonged hypocalcemia after a single dose of denosumab for metastatic breast cancer with diffuse bone involvement without prior calcium/vitamin D supplementations.

INTRODUCTION: Denosumab is a human monoclonal antibody antiresorptive agent used for the treatment of bone metastasis in different cancer types, including breast cancer. Hypocalcemia is a known adverse effect of denosumab, and early supplementation plays an important role in the prevention and management of hypocalcemia. CASE REPORT: A 63-year-old female with stage IV estrogen receptor-positive breast cancer with diffuse bone metastasis experienced severe, prolonged hypocalcemia following a single dose of denosumab. The patient also had several risk factors for denosumab-associated hypocalcemia. Despite not receiving additional doses of denosumab, the patient required multiple hospitalizations and outpatient infusions of calcium to resolve her symptomatic hypocalcemia.Management and outcome: Severe hypocalcemia associated with denosumab can be prevented or mitigated by recognizing the risk factors for hypocalcemia and supplementing with vitamin D/calcium. Proposed risk factors include poor renal function, hypoparathyroidism, insufficient calcium intake, and diffuse metastatic bone disease. Studies suggest that early supplementation before starting denosumab can lower this risk. DISCUSSION: Several cases of severe hypocalcemia associated with denosumab have been reported. However, to the authors' knowledge, this is the first report that highlights the importance of early vitamin D/calcium supplementations for a patient with diffuse metastatic bone disease with pre-existing low levels of calcium.

Characterizing the impact of magnesium and potassium-supplemented hydration with cisplatin and the subsequent electrolyte replacement requirements.

BACKGROUND: Cisplatin-associated electrolyte dysregulation is a prevalent therapy-related adverse effect. There are numerous electrolyte-supplemented hydration regimens that have been evaluated, however these studies focused on the development of nephrotoxicity. The objective of this study was to characterize the impact of magnesium and potassium-supplemented hydration during cisplatin administration on subsequent magnesium and potassium imbalances. METHODS: A single-region retrospective study from central Texas at Baylor Scott & White Cancer Clinics who were treated with two or more cycles of cisplatin were included. Standard hydration for this study was defined as normal saline before and after cisplatin along with potassium chloride 10 mEq and magnesium sulfate 1 g added to the cisplatin bag. RESULTS: A total of 477 patients were included in the study with376 patients receiving the standard hydration. Overall, 17 percent of patients experienced a potassium level below 3.5 mEq/L, but no major depletion was observed. Thirty-three percent of the patients experienced a magnesium level below 1.8 mg/dL, and time to first rescue magnesium supplementation was 4 weeks. CONCLUSION: Our study demonstrated despite routine magnesium and potassium supplementation in hydration, magnesium imbalances were observed. Potassium levels post cisplatin administration were maintained with minimal routine supplementation in hydration.

Retrospective comparison of low molecular weight heparin vs. warfarin vs. oral Xa inhibitors for the prevention of recurrent venous thromboembolism in oncology patients: The Re-CLOT study.

Background There is increasing evidence indicating oral factor Xa inhibitors can be used for secondary prevention of venous thromboembolism. Studies are needed to compare oral factor Xa inhibitors, low molecular weight heparins, and warfarin in the oncology population. The purpose of this study is to evaluate the recurrent venous thromboembolism incidence in oncology patients utilizing oral Xa inhibitors, low molecular weight heparins, or warfarin. Methods Using retrospectively collected data, we compared the recurrent venous thromboembolism incidence in oncology patients taking rivaroxaban/apixaban, enoxaparin, or warfarin with at least three months of follow-up. Patients were included if they had an active cancer, venous thromboembolism, and taking warfarin, enoxaparin, or rivaroxaban/apixaban. The primary endpoint was the first episode of recurrent venous thromboembolism at three months. Secondary endpoints included recurrent venous thromboembolism after six months, major bleeding, and mortality. Results Of 127 venous thromboembolism patients, 48 received rivaroxaban or apixaban, 23 received enoxaparin, and 56 received warfarin. The three most common cancer diagnoses were lung (21%), colorectal (14%), and breast (14%). There was no difference in venous thromboembolism recurrence at three months between the rivaroxaban/apixaban (0%), warfarin (3.6%), and the enoxaparin cohorts (4.4%) (p = 0.8319). Major bleeding at three months was only seen in one patient in the enoxaparin arm (4.2%). Mortality at three months was 0%, 3.6%, and 17.4% in the rivaroxaban/apixaban, warfarin, and enoxaparin cohorts, respectively. Conclusion The results of this retrospective study suggest that oral factor Xa inhibitors are potential options for cancer patients with venous thromboembolism. However, randomized, controlled trials are needed to confirm these results.

High- versus low-dose leucovorin in the modified FOLFOX6 regimen for first-line treatment of metastatic colorectal cancer.

Background In response to the national leucovorin shortage in 2008, our institution adjusted the modified FOLFOX6 (leucovorin, fluorouracil, and oxaliplatin) protocol to utilize a lower dose of leucovorin (20 mg/m2). This adjustment was based on prospective studies suggesting that lower doses of leucovorin may be equally effective in other fluorouracil containing regimens. This retrospective study evaluates outcomes in metastatic colorectal cancer (mCRC) patients treated with low- (20 mg/m2) vs. high-dose (400 mg/m2) leucovorin in the FOLFOX6 regimen for mCRC. Methods This retrospective analysis included consecutive mCRC patients from 2004 to 2011 if they received at least one cycle of modified FOLFOX6 as first line therapy. Patients who received an initial leucovorin dose other than 20 mg/m2 or 400 mg/m2 on their first cycle were excluded. Patient characteristics included demographics, metastatic site at initial diagnosis, and treatment history including chemotherapy and surgery. Primary outcome was date of death or last contact. Cox proportional hazards regression analysis and Kaplan-Meier survival curves were utilized to evaluate the effect of leucovorin dose on overall survival. Log-rank tests were used to compare median survival times by dose group. Results Of the 93 mCRC patients who received first line modified FOLFOX6, leucovorin 400 mg/m2 was administered to 47 (51%) patients and 20 mg/m2 to 46 (49%) patients. There were no differences of baseline characteristics between the groups with exception of primary site of cancer ( p = 0.038). The overall survival time was 22.5 months (95% CI 16.6-29.6). The median survival time in the leucovorin 400 mg/m2 group was 23.1 months (95% CI 16.2-35.7) compared to leucovorin 20 mg/m2 which was 20.5 months (95% CI 14.2-34.2); p = 0.573. The median survival times in patients with one versus two or more sites with metastasis were statistically different (26.9 vs. 16.2 months, p = 0.009). Metastatic site removal or ablation showed differences in the median survival, 34.2 months (95% CI 20.8-50.9) vs. 16.6 months (95% CI 14.1-23.6) without metastatic disease removal ( p = 0.004). The odds of dying for patients with two metastatic sites was higher compared with the odds of those patients with one site, HR 1.8 (95% CI 1.08-3.0). Patients without metastatic site removal or ablation had higher odds of dying compared to those patients without this procedure, HR 0.47 (95% CI 0.27-0.81). Conclusion In this single center retrospective study, there was no difference in overall survival for mCRC patients treated with first line FOLFOX6 with low- vs. high-dose leucovorin.