Tumor lysis

Sood AR, Burry LD, Cheng DK (2007) Clarifying the role of rasburicase in tumor lysis syndrome. Pharmacotherapy 27 111-121... 

If present and clinically feasible, treat acute severe hyperphosphatemia before calcium administration (i.e., with hemodialysis in acute tumor lysis syndrome)... 

Prior to initiation of treatment with chemotherapy, determine if tumor lysis syndrome precautions need to be implemented. 

RH is admitted to the pediatric oncology service. She is started on allopurinol and intravenous fluids with sodium bicarbonate to prevent tumor lysis syndrome. According to her risk status, she will receive a three-drug induction with vincristine, dexamethasone, and pegylated asparaginase. She also will receive intrathecal (IT) chemotherapy for CNS prophylaxis with methotrexate, cytarabine, and hydrocortisone. 

The primary goals of management of tumor lysis syndrome are (1) prevention of renal failure and (2) prevention of electrolyte imbalances. Thus the best treatment for tumor lysis syndrome is prophylaxis to enable delivery of cytotoxic therapy for the underlying malignancy. 

Although not as common as hypercalcemia, tumor lysis syndrome may cause significant morbidity and mortality if adequate prophylaxis and treatment are not instituted. Tumor lysis syndrome is the result of rapid destruction of malignant cells with subsequent release of intracellular contents into the circulation. 

What risk factors does HT have for tumor lysis syndrome Why is the serum uric acid elevated and renal function decreased ... 

TABLE 96-11. Risk Factors for Tumor Lysis Syndrome... 

Patients with tumor lysis syndrome experience a wide range of metabolic abnormalities. The massive cell lysis that occurs leads to the release of intracellular electrolytes, resulting in hyperkalemia and hyperphosphatemia. High concentrations of phosphate bind to calcium, leading to hypocalcemia and calcium phosphate precipitation in the renal tubule. Purine nucleic acids are also released that are subsequently metabolized to uric acid... 

When should tumor lysis syndrome prophylaxis begin for HT ... 

If tumor lysis syndrome develops, how would you modify your management approach ... 

The primary goals of management of tumor lysis syndrome are (1) prevention of renal failure and (2) prevention of electrolyte imbalances. Thus the best treatment for tumor lysis syndrome is prophylaxis to enable delivery of cytotoxic therapy for the underlying malignancy. For patients who present with or develop tumor lysis syndrome despite prophylaxis, treatment goals include (1) decrease uric acid levels, (2) correct electrolyte imbalances, and (3) prevent compromised renal function. These goals should be achieved in a cost-effective manner. 

Prevention of tumor lysis syndrome generally is achieved by increasing the urine output and preventing accumulation of uric acid. Prophylactic strategies should begin immediately on presentation, preferably 48 hours prior to cytotoxic therapy. Treatment modalities primarily increase uric acid solubility, address electrolyte disturbances, and support renal output. 

Prophylaxis and treatment of hyperuricemia associated with tumor lysis syndrome. ALL, acute lymphoblastic leukemia AML, acute myelogenous leukemia IV, intravenous. (Data from refs. 32 and 33.)... 

Pharmacologic prevention strategies for tumor lysis syndrome are aimed at low- and high-risk patients (Fig. 96-7). Allopurinol is a xanthine oxidase inhibitor that is used for prevention only because it has no effect on preexisting elevated uric acid. Rasburicase is a recombinant form of urate oxidase that is useful for both prevention and treatment but is extremely expensive (Table 96-12). Although the approved dose is 0.2 mg/kg per day... 

Electrolyte disturbances that develop in patients with tumor lysis syndrome should be managed aggressively to avoid renal failure from hyperphosphatemia and hypocalcemia and cardiac signs from hyperkalemia. One exception pertains to the use of intravenous calcium for hypocalcemia. Adding calcium may cause further calcium phosphate precipitation in the presence of hyperphosphatemia and should be used cautiously. 

Cairo MS, Bishop M. Tumor lysis syndrome New therapeutic strategies and classification. Br J Hematol 2004 127 3-11. 

Cladribine (2-CdA) -purine analogue antimetabolite -bone marrow suppression -fever in 50% (probably due to tumor lysis) -rash in 50% -immunosuppression (with profound T-cell lymphopenia)... 

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