Introduction
Burkitt lymphoma (BL) is an extremely aggressive form of non-Hodgkin B-cell lymphoma. This disease is characterized by its association with the Epstein-Barr virus (EBV), the human immunodeficiency virus (HIV), and chromosomal translocations that lead to the overexpression of the oncogene C-MYC. The World Health Organization (WHO) categorizes BL into three clinical subtypes: endemic, sporadic, and immunodeficiency-related.
The endemic form is connected to malaria and EBV, while the immunodeficiency-related variant is linked primarily to HIV infection and, to a lesser extent, organ transplantation. While children generally have an excellent prognosis with intensive chemotherapy treatment, the outlook for adults with BL is typically poor. Hypophosphatemia, characterized by serum phosphorus levels below 2.5 mg/dL, is a common occurrence among cancer patients and is linked to increased morbidity and mortality.
Phosphorus plays a vital role in the normal physiological functioning of all cells, and disruptions in its homeostasis are frequently observed in the context of cancer and cancer treatments. This article provides a comprehensive review of hypophosphatemia in Burkits lymphoma. It is important to note that phosphorus is typically introduced into our bodies as phosphate. This review aims to explore drug-induced hypophosphatemia, focusing on its underlying mechanisms and the latest insights to enhance clinicians' understanding of timely diagnosis and appropriate management.
What Is Hypophosphatemia?
Hypophosphatemia is defined as serum phosphate levels below 2.5 mg/dL (0.81 mmol/L) and is further classified into mild, moderate, or severe based on specific thresholds. A wide range of commonly used drugs, including intravenous glucose solutions, antacids, diuretics, corticosteroids, and newer medications like antibiotics, antiviral agents, antiosteoporotic drugs, antineoplastic agents, and intravenous iron, have been associated with hypophosphatemia.
Phosphate plays a vital role in numerous biochemical processes, such as:
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Energy metabolism.
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Nucleic acid synthesis.
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Cellular signaling.
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Bone formation.
Hypophosphatemia, characterized by serum phosphate levels below 2.5 mg/dL (0.81 mmol/L), often occurs during treatment with commonly prescribed drugs like diuretics, bisphosphonates, antibiotics, insulin, and antacids. New medications such as teriparatide, denosumab, parenteral iron, and certain antiviral and antineoplastic agents can also contribute to this undesired effect.
Phosphate is a crucial component in cellular membranes, enzyme systems, nucleic acids, and various nucleoproteins, participating in essential biochemical pathways such as bone formation, energy metabolism, and cellular signaling. Maintaining serum phosphate concentrations within normal limits is vital for optimal cellular function. Phosphate is present in organic and inorganic forms, with the inorganic form being a major component of bone hydroxyapatite. Although drug-induced hypophosphatemia is typically mild and asymptomatic, it can lead to severe complications, particularly when multiple drugs are used concurrently or when baseline phosphate levels are low.
What Are Effects Of Hypophosphatemia in Burkits Lymphoma?
Recent advancements in cancer treatment have led to improved therapeutic outcomes for advanced cancer patients, thanks in part to the development of molecular-targeted therapies and other agents. Notably, there has been a global increase in the number of survivors of breast and colorectal cancers, with 5-year survival rates exceeding 60% and 85%, respectively.
Similarly, prostate cancer has seen a remarkable 5-year survival rate of over 95% in many countries. However, as survival times lengthen, there is a growing need to maintain patients' quality of life. The management of adverse events associated with these newer therapies differs from those previously observed with cytotoxic agents.
For instance, antiangiogenic agents like Bevacizumab and Ramucirumab can induce hypertension and thrombosis, while anti-epidermal growth factor receptor antibodies such as Cetuximab and Panitumumab may cause acne-like rash, paronychia, and hypomagnesemia.
Additionally, severe hand-foot syndrome can result from multiple tyrosine kinase inhibitors like Regorafenib, and hypocalcemia may occur with bone-modifying agents like Zoledronic acid and Denosumab. Moreover, prolonged survival times may impact the general condition of advanced cancer patients, leading to unforeseen situations.
Hypophosphatemia, often referred to as oncogenous osteomalacia, is associated with cancer and may be induced by various medications, particularly molecular-targeted agents. The incidence of severe hypophosphatemia has been reported in patients treated with drugs such as zoledronic acid, denosumab, imatinib, dasatinib, sunitinib, and dabrafenib.
Tumor-induced osteomalacia (TIO), associated with hypophosphatemia, is commonly linked to mesenchymal tumors, and fibroblast growth factor-23 (FGF-23) is implicated in its pathogenesis. However, hypophosphatemia in cancer patients can also be influenced by factors such as the patient's general condition and medication use. The body's phosphorus regulation involves complex mechanisms mediated by various hormones and factors. The complexity of hypophosphatemia in advanced cancer patients, studies sought to investigate its prevalence and severity in recent cases.
The observational study examined serum inorganic phosphorus levels and gathered additional data from electronic medical records, including patient demographics, cancer characteristics, medication history, and laboratory values. Studies have not confirmed the effectiveness of Hypophosphatemia in Burkits lymphoma.
What Are the Mechanisms for Hypophosphatemia in Burkits Lymphoma?
Eighty-five percent of the body's phosphorus is found in bone tissue, with intracellular phosphorus levels closely mirroring those in extracellular fluid. Hypophosphatemia occurs when phosphorus moves from the extracellular fluid into cells. Several factors can contribute to this transfer, including insulin, glycolysis, respiratory alkalosis, leukemia, malignant lymphoma, and catecholamines. Additionally, hormones like parathyroid hormone and certain diuretics promote phosphorus excretion in urine, leading to hypophosphatemia.
Malabsorption, deficiency in active vitamin D, and aluminum ingestion can disrupt phosphorus absorption from the intestine, further exacerbating hypophosphatemia. Temporary decreases in extracellular fluid phosphorus levels may be compensated for by releasing stored phosphorus from bone tissue. In this study, hypophosphatemia was observed frequently in cancer patients, with rates as high as 50% (grade ≥2) or 20%. Hypophosphatemia can cause muscle injury, nerve paralysis, and red blood cell damage (hemolysis).
However, symptoms are often only noticeable once serum inorganic phosphorus (IP) levels drop below 1 mg/mL. Therefore, the need for therapeutic intervention for hypophosphatemia remains a topic of debate. Nonetheless, even mild hypophosphatemia has been associated with poor clinical outcomes. When serum IP levels fall below 2.0 mg/dL, oral phosphorus supplementation is recommended to maintain a minimum of 2.0 mg/dL, even without symptoms. While intravenous administration of phosphorus is an alternative option, it can be risky and should be avoided due to the potential to cause hyperphosphatemia.
Conclusion
In conclusion, studies have shown that regulating phosphorus levels in the body is more complex than regulating the balance of the body, which is regulated by various factors. There may be risk factors for hypophosphatemia during the disease duration. Monitoring phosphorous levels is important in long-term survivors and advanced cancer patients. Patients with bone cancer with low serum or calcium levels should also be monitored. The significance of hypophosphatemia needs to be understood, as it is not warranted in a larger population.
