Body Jean-Jacques, Niepel Daniela, Tonini Giuseppe
Department of Medicine (K1), CHU Brugmann (Université Libre de Bruxelles), Place Van Gehuchten, 1020, Brussels, Belgium.
Amgen (Europe) GmbH, Vienna, Austria.
Support Care Cancer. 2017 May;25(5):1639-1649. doi: 10.1007/s00520-016-3543-1. Epub 2017 Jan 12.
The balance between bone formation and resorption may be disrupted in patients with cancer, leading either to increased bone resorption, calcium release, and possibly hypercalcaemia, or to increased bone formation, sequestration of calcium, and possibly hypocalcaemia. In adults, hypercalcaemia of malignancy is most common in patients with tumours that produce factors that induce osteoclast activation and enhance bone resorption. Impaired renal function and increased renal tubular calcium resorption may further affect calcium levels.
Inhibitors of bone resorption, first the bisphosphonates and, later, denosumab, have been shown to be effective in hypercalcaemia treatment. Bisphosphonates (which are administered intravenously) are approved for hypercalcaemia of malignancy and are the current mainstay of treatment, whereas denosumab (which is administered subcutaneously) may offer an option for patients who do not respond to bisphosphonates or suffer from renal insufficiency.
TREATMENT AND PREVENTION: Hypocalcaemia is most common in patients with prostate cancer and osteoblastic bone metastases, but can occur in patients with a variety of tumour types who are receiving inhibitors of bone resorption. While patients often respond to calcium and vitamin D supplementation, prevention should be the aim; at-risk patients should be identified before starting treatment with inhibitors of bone resorption, be closely monitored during at least the first few months of treatment, and receive concomitant calcium and vitamin D supplementation unless hypercalcaemia is present.
Both hypercalcaemia and hypocalcaemia can be serious if left untreated. It is therefore important that patients with cancer are closely monitored and receive adequate prevention and treatment measures to maintain normal blood calcium levels.
癌症患者骨形成与骨吸收之间的平衡可能被打破，导致骨吸收增加、钙释放，进而可能引发高钙血症；或者导致骨形成增加、钙潴留，进而可能引发低钙血症。在成年人中，恶性肿瘤高钙血症在产生诱导破骨细胞活化并增强骨吸收因子的肿瘤患者中最为常见。肾功能受损和肾小管钙重吸收增加可能进一步影响钙水平。
骨吸收抑制剂，首先是双膦酸盐，后来是地诺单抗，已被证明对高钙血症治疗有效。双膦酸盐（静脉给药）被批准用于治疗恶性肿瘤高钙血症，是目前的主要治疗方法，而地诺单抗（皮下给药）可能为对双膦酸盐无反应或患有肾功能不全的患者提供一种选择。
治疗与预防：低钙血症在前列腺癌和成骨性骨转移患者中最为常见，但在接受骨吸收抑制剂治疗的各种肿瘤类型患者中也可能发生。虽然患者通常对补充钙和维生素D有反应，但应以预防为目标；在开始使用骨吸收抑制剂治疗前应识别高危患者，在治疗的至少前几个月密切监测，除非存在高钙血症，应同时补充钙和维生素D。
高钙血症和低钙血症如果不治疗都可能很严重。因此，密切监测癌症患者并采取适当的预防和治疗措施以维持正常血钙水平非常重要。
