Hyperuricemia in Patients with Cancer

Hyperuricemia is a common early complication in patients with hematological malignancies treated with intensive chemotherapy. It results from the breakdown of nuclear proteins leading to increased blood levels of hypoxanthine and xanthine. These compounds are degraded into uric acid by the enzyme xanthine oxidase. Because the mechanisms of excretion of uric acid are limited in humans and blood levels are near saturation level, a common complication of hyperuricemia is renal failure resulting from the deposition of uric acid in renal tubules. When renal insufficiency occurs in conjunction with other metabolic aberrations, such as hyperkalemia, hyperphosphatemia, and hypocalcemia, this process is termed tumor lysis syndrome. Patients with acute lymphoblastic leukemia and non-Hodgkin’s lymphoma, particularly Burkitt’s lymphoma, are at greatest risk because of the high sensitivity of the cells to chemotherapy. Other factors associated with increased risk of hyperuricemia and tumor lysis syndrome include hyperleukocytosis, massive organomegaly, renal enlargement, extrinsic compression of the genitourinary tract, and elevated serum lactate dehydrogenase activity. Conventionally, patients at risk of developing hyperuricemia receive alkalinized fluids and allopurinol, an inhibitor of the enzyme xanthine oxidase. These measures have been effective in reducing mortality associated with metabolic complications during tumor lysis in the majority of the cases. However, as many as 25% of patients at high-risk of developing tumor lysis syndrome require dialysis, and some of them have the treatment course altered because of these complications. Recently, a synthetic recombinant form of the enzyme urate oxidase, rasburicase has become available in the US. This enzyme acts directly on urate and degrades it to allantoin, a much more soluble compound.     

Elitek-rasburicase: an effective means to prevent and treat hyperuricemia associated with tumor lysis syndrome, a Meeting Report, Dallas, Texas, January 2002.

Renal precipitation of uric acid associated with tumor lysis syndrome (TLS) is a major complication in the management of leukemia, lymphoma, and other drug-sensitive cancers. Management of hyperuricema has historically consisted of administration of allopurinol, hydration, alkalinization to maintain pH between 7.0 and 7.3, and in some cases diuresis. Allopurinol, a xanthine analogue, blocks xanthine oxidase and formation of uric acid. Urate oxidase converts uric acid to allantoin, which is 5-10 times more soluble than uric acid. Homo sapiens cannot express urate oxidase because of a nonsense mutation. Urate oxidase was initially purified from Aspergillus flavus fungus. Treatment with this nonrecombinant product had been effective in preventing renal precipitation of uric acid in cancer patients, but was associated with a relatively high frequency of allergic reactions. This enzyme was recently cloned from A. flavus and is now manufactured as a recombinant protein. Clinical trials have shown this drug to be more effective than allopurinol for prevention and treatment of hyperuricemia in leukemia and lymphoma patients. This drug has been approved in Europe as well as the US and several clinical trials are in progress to further determine its clinical utility in other patient subsets. The purpose of this meeting was to discuss usefulness of recombinant urate oxidase, also known as rasburicase, Fasturtec, and Elitek, for the management of TLS in certain cancer patients.     

Management of tumor lysis syndrome in adults

Spontaneous or treatment-induced tumor lysis syndrome (TLS) can cause significant morbidity and potential mortality. Vigorous hydration, alkalinization and inhibition of uric acid synthesis with allopurinol are the most frequently used methods for treatment and prevention of TLS. However, this approach fails to prevent renal insufficiency in up to 25% of high-risk patients. With the increased intensity and efficacy of cancer therapies, novel approaches for the management of TLS are needed. Unlike allopurinol, urate oxidase promptly reduces the existing uric acid pool, prevents accumulation of xanthine and hypoxanthine and does not require alkalinization, facilitating phosphorus excretion. A recombinant form of urate oxidase, rasburicase, is now registered for the treatment and prevention of TLS. This review provides an overview of rasburicase development and discusses the impact of rasburicase in the prevention and management of TLS.     

Management of tumor lysis syndrome in adults

Spontaneous or treatment-induced tumor lysis syndrome (TLS) can cause significant morbidity and potential mortality. Vigorous hydration, alkalinization and inhibition of uric acid synthesis with allopurinol are the most frequently used methods for treatment and prevention of TLS. However, this approach fails to prevent renal insufficiency in up to 25% of high-risk patients. With the increased intensity and efficacy of cancer therapies, novel approaches for the management of TLS are needed. Unlike allopurinol, urate oxidase promptly reduces the existing uric acid pool, prevents accumulation of xanthine and hypoxanthine and does not require alkalinization, facilitating phosphorus excretion. A recombinant form of urate oxidase, rasburicase, is now registered for the treatment and prevention of TLS. This review provides an overview of rasburicase development and discusses the impact of rasburicase in the prevention and management of TLS.     

Prevention and treatment of hyperuricemia in hematological malignancies

The standard prophylactic and treatment regimen for hyperuricemia in patients with hematological malignancies previously included vigorous hydration, urinary alkalinization, and a xanthine oxidase inhibitor, allopurinol, which blocks the conversion of hypoxanthine and xanthine to uric acid. However, xanthine is less soluble than uric acid, and preexisting uric acid is not affected by allopurinol. The enzyme urate oxidase, not present in mammals, converts uric acid to allantoin, which is 5-10 times more soluble than uric acid. A new recombinant form of urate oxidase, rasburicase, has recently been developed. In a phase I/II study of rasburicase in children and young adults with hematological malignancies, rasburicase was demonstrated to be well tolerated at 0.2 mg/kg/day intravenously, had a mean T1/2 of 21.2 +/- 12.0 hours, and induced a median decrease in uric acid from 9.7 mg/dL to 1.0 mg/dL (P < 0.001). We recently demonstrated, in a randomized prospective trial comparing rasburicase versus allopurinol in children with hematological malignancies at high risk of tumor lysis syndrome, that rasburicase significantly lowered the mean uric acid area under the curve 0 to 96 hours (128 +/- 70 mg/dL/hour vs. 329 +/- 129 mg/dL/hour; P < 0.001) and 4 hours post uric acid by 86% versus 12% (P < 0.001). Furthermore, in the hyperuricemic group, the baseline creatinine level decreased from 144% to 102% by 96 hours following rasburicase compared to an increase from 132% to 147% following allopurinol. Although the difference in effect on creatinine levels is not significant, the study was not designed or powered to question this effect. Lastly, in 510 patients with hematological malignancies at risk for tumor lysis syndrome who received rasburicase, only 2 (0.4%) have developed new renal complications requiring hemodialysis. In summary, in the prevention and treatment of hyperuricemia, patients with hematological malignancies at risk of tumor lysis syndrome appear to benefit significantly from the use of a recombinant urate oxidase (rasburicase).     

Single-Dose Rasburicase Might Be Adequate To Overcome Tumor Lysis Syndrome In Hematological Malignancies

IntroductionTumor lysis syndrome (TLS) is a commonly observed oncological emergency that requires prompt diagnosis and treatment. Rasburicase is a recombinant urate oxidase endorsed in TLS for the treatment of hyperuricemia. The effect of single-dose 7.5 mg rasburicase at longer follow-ups was not widely investigated.Patients and MethodsEighty-two patients included in the study with clinical TLS and laboratory TLS. The primary endpoint was the normalization of uric acid (<6mg/dL) within 24 hours of rasburicase administration, which was described as treatment success. The secondary endpoint was defined as having sustained response at the first week. The third endpoint was defined as the reaching the baseline renal function before TLS.ResultsWe found that the use of a 7.5 mg dose of rasburicase controlled uric acid in 74 of 82 (90,2%) patients at the 24th hour. In the first week, uric acid remained at normal levels in 69 of 82 (84,1%) patients. At 24 hours, the TLS risk group was the only predictor for failing uric acid normalization; at the end of the first week, no predictive factor was identified for failing uric acid normalization.ConclusionRasburicase at 7.5 mg dose is an important agent for controlling laboratory and clinical TLS at 24 hours and extending its effect to the first week.     

急性淋巴细胞白血病并发肿瘤溶解综合征7例

目的 :探讨急性淋巴细胞白血病 (AL L )患者化疗后发生肿瘤溶解综合征 (TL S)的临床特征。方法 :对 7例化疗发生 TL S的 AL L患者进行各项生化指标的分析。结果 :TL S患者表现为高尿酸血症、高血钾、高血磷、低血钙 ,并有不同程度的肾功能损伤 ,其中 1例发生了急性肾功能不全。用别嘌呤醇及静脉碱化利尿后 ,6例短期内血生化指标恢复正常。1例死于心衰。结论 :早期诊断并及时给予别嘌呤醇及静脉碱化利尿是治疗 TL S的关键     

Recombinant urate oxidase for prevention of hyperuricemia and tumor lysis syndrome in lymphoid malignancies

Hyperuricemia is a common manifestation of lymphoid malignancies at diagnosis or after the start of chemotherapy. When accompanied by other metabolic abnormalities and/or organ failure, hyperuricemia may be a manifestation of tumor lysis syndrome (TLS). Patients at particularly high risk of such complications include those with acute lymphoblastic leukemia and advanced stage non-Hodgkin's lymphoma. Conventional measures to prevent hyperuricemia and TLS are comprised of hydration, alkalinization of body fluids, and administration of allopurinol. Although these measures are usually effective in preventing or managing hyperuricemia, approximately 20% of patients at high risk of TLS require dialysis, and many cannot receive chemotherapy as planned. Rasburicase, a recombinant form of the enzyme urate oxidase, has recently become available and may further reduce the morbidity of hyperuricemia and TLS. In this review, we provide an overview of hyperuricemia and TLS and discuss the impact of rasburicase in the overall management of these complications.     

Rasburicase: potential role in managing tumor lysis in patients with hematological malignancies

Acute tumor lysis syndrome with hyperuricemia and renal failure usually occurs during the initial period of chemotherapy in patients with aggressive hematological malignancies. Standard therapy for hyperuricemia includes hydration, urine alkalinization and pharmacoreduction of uric acid with allopurinol. In the USA, rasburicase has recently been approved by the US Food and Drug Administration for the reduction of uric acid. Rasburicase is a recombinant urate oxidase enzyme that converts uric acid to allantoin, which has increased urine solubility. It is administered intravenously once-daily and leads to rapid, dramatic declines in serum uric acid values. The toxicity profile is excellent, with rare incidence of bronchospasm and allergies and a known contraindication for patients with glucose-6-phosphate dehydrogenase deficiency. A Phase III trial in high-risk pediatric patients conclusively demonstrated that rasburicase is more effective than allopurinol in controlling uric acid. Ongoing evidence is accumulating suggesting that the drug is also safe and effective in adults with hematological malignancies.     

Rasburicase: potential role in managing tumor lysis in patients with hematological malignancies

Acute tumor lysis syndrome with hyperuricemia and renal failure usually occurs during the initial period of chemotherapy in patients with aggressive hematological malignancies. Standard therapy for hyperuricemia includes hydration, urine alkalinization and pharmacoreduction of uric acid with allopurinol. In the USA, rasburicase has recently been approved by the US Food and Drug Administration for the reduction of uric acid. Rasburicase is a recombinant urate oxidase enzyme that converts uric acid to allantoin, which has increased urine solubility. It is administered intravenously once-daily and leads to rapid, dramatic declines in serum uric acid values. The toxicity profile is excellent, with rare incidence of bronchospasm and allergies and a known contraindication for patients with glucose-6-phosphate dehydrogenase deficiency. A Phase III trial in high-risk pediatric patients conclusively demonstrated that rasburicase is more effective than allopurinol in controlling uric acid. Ongoing evidence is accumulating suggesting that the drug is also safe and effective in adults with hematological malignancies.     

Single dose rasburicase in tumor lysis: One hospital's experience

Background: Tumor lysis syndrome is an oncological emergency occurring mainly in high‐grade hematological malignancies. It results in significant biochemical abnormalities including hyperuricemia and acute renal failure. Rasburicase is a recombinant urate oxidase enzyme that catalyzes oxidation of uric acid into allantoin, which is easily excreted in the urine. Reports in the literature suggest that a single dose of rasburicase is effective in treating tumor lysis syndrome, whereas the current dose recommended by the manufacturer is 0.2 mg/kg/day for 5 to 7 days, which is very costly ($13 000 for an average 70‐kg person). We present a retrospective analysis on the patients at our hospital that have received rasburicase as a single dose. Methods: Medical and pharmacy dispensing records were searched to identify patients with high‐grade hematological malignancy who received a single dose of rasburicase in a 12‐month period. Data on renal function, electrolytes, and uric acid were obtained. Results: Twenty‐three patients were newly diagnosed with high‐grade hematological malignancy (Burkitt lymphoma 4, AML 17, APML 1, DLBCL 1). A single dose of rasburicase 0.2 mg/kg was administered to six of these patients considered to be at high risk, five of whom had an elevated uric acid level before treatment. Their uric acid levels were monitored from 24 h to 96 h after this dose. Normal uric acid levels were seen in all patients within 24 h. These levels remained normal for 96 h. One of five patients died of pre‐existing renal failure despite the normalization of their uric acid. Conclusion: We conclude that single dose rasburicase is effective in the treatment of hyperuricemia in patients at risk of tumor lysis and effectively reduces the level of uric acid for up to 96 h. This makes it cost effective and theoretically reduces the risk of hypersensitivity associated with rasburicase.     

Managing malignancy-associated hyperuricemia with rasburicase

Along with hydration and urinary alkalinization, allopurinol has been the standard agent for the management of hyperuricemia in patients with a high tumor burden who are at risk for tumor lysis syndrome. However, this agent often fails to prevent and treat this complication effectively. Rasburicase, a recombinant urate oxidase, acts at the end of the purine catabolic pathway and, therefore, does not induce accumulation of xanthine or hypoxanthine, which can precipitate in the kidneys and lead to impaired renal function. Rasburicase may represent an effective alternative to allopurinol in rapidly reducing uric acid levels, improving patients' electrolyte status, and reversing renal insufficiency. The drug initially was studied in pediatric patients with acute lymphoblastic leukemia and aggressive non-Hodgkin lymphoma; data may suggest comparable benefit in adults with similar lymphoid malignancies. Current and future trials will evaluate alternate doses and schedules of rasburicase to maintain its efficacy while reducing its cost.     

Rasburicase (recombinant urate oxidase) for the management of hyperuricemia in patients with cancer: report of an international compassionate use study

BACKGROUND: Hyperuricemia and tumor lysis syndrome (TLS) are serious complications that can occur during chemotherapy for hematologic malignancies, even if standard management procedures, including administration of allopurinol, are undertaken. Rasburicase, a recombinant urate oxidase that converts uric acid (UA) into the soluble compound allantoin, has been shown to control hyperuricemia faster and more reliably than allopurinol.(1) METHODS: A compassionate use trial, running from January 1999 to December 2001, provided access to rasburicase for patients in nine countries who were at risk for TLS during the initiation of chemotherapy. Of the 280 patients enrolled in the study, 278 received rasburicase and were included in the analysis. A total of 166 pediatric patients who had leukemia (approximately 74%), lymphoma (approximately 24%), or solid tumors (approximately 3%) were treated with rasburicase. One hundred twelve adults with either leukemia (68%) or lymphoma (30%) also were treated. Rasburicase (0.20 mg/kg) was administered intravenously once a day for 1 to 7 days, at the investigator's discretion. Two doses daily could be administered during the first 3 days. A response was defined as a reduction in UA level or maintenance of a UA level less than 7.5 mg/dL (or less than 6.5 mg/dL, for children age < 13 years). RESULTS: UA levels at 24-48 hours after administration of the last dose of rasburicase were available for 122 pediatric patients and 97 adult patients. The mean UA level in 29 hyperuricemic children decreased from 15.1 mg/dL to 0.4 mg/dL, whereas in 27 hyperuricemic adults, the mean level decreased from 14.2 mg/dL to 0.5 mg/dL. Prophylactic administration of rasburicase to prevent TLS during chemotherapy reduced UA levels from a mean of 4.4 mg/dL to 0.8 mg/dL in 93 nonhyperuricemic children and from 4.8 mg/dL to 0.4 mg/dL in 70 nonhyperuricemic adults (for all reductions in UA levels, P < 0.001). The response rate was 100%. Rasburicase was very well tolerated. Serious adverse events related to rasburicase were observed in one patient. CONCLUSIONS: The results of the current study confirm that rasburicase is safe and highly effective in the prevention and treatment of chemotherapy-induced hyperuricemia in both children and adults.     

Efficacy of Single Low-Dose Rasburicase in Management of Tumor Lysis Syndrome in Leukemia and Lymphoma Patients

BackgroundTumor lysis syndrome (TLS) is a metabolic emergency in hematology patients. The recommended dose of rasburicase for the management of TLS is 0.2 mg/kg per day for 5 days, which is cost prohibitive for many patients. We sought to determine the efficacy of single low-dose rasburicase in the prevention and treatment of hyperuricemia in TLS.Patients and MethodsWe planned a prospective study for the safety and efficacy of fixed (weight based) dose of rasburicase to manage TLS. Patients diagnosed with leukemia/lymphoma with laboratory or clinically confirmed TLS or presence of ≥ 2 high-risk factors and serum uric acid > 7.5 mg/dL were included. The primary endpoint was uric acid normalization (< 7.5 mg/dL) within 24 hours of rasburicase administration.ResultsFifty-five patients were recruited for this study. Pediatric patients (< 18 years) accounted for 43.6% of cases. Rasburicase was provided prophylactically to 43 patients (78.2%) and for treating TLS to 12 (21.8%). Mean ± standard deviation serum uric acid at baseline and 24 hours was 9.2 ± 1.8 mg/dL and 3.2 ± 2.1 mg/dL, respectively. There was significant reduction in the serum uric acid and creatinine (P < .001) within 24 hours of rasburicase administration. The response was maintained up to 72 hours. A single dose of rasburicase was effective in 94.5% of patients. Single low-dose rasburicase led to 95% direct cost savings compared to the recommended dose.ConclusionSingle-dose rasburicase with frequent laboratory monitoring is effective in the management of TLS and offers significant cost reductions.     

Tumor lysis syndrome following hemi-body irradiation for metastatic breast cancer

Tumor lysis syndrome (TLS) is a rare serious acute complication of cancertherapy, reported mainly following chemotherapy in patients with large tumorload and chemosensitive disease. These are mainly patients with non-Hodgkin'slymphoma, leukemia and rarely in solid tumors. It is less frequently describedafter radiotherapy for lymphoid and hematological malignancies. TLS followingradiotherapy for solid tumors is a very rare complication. In thisreport/review we describe a seventy-three-year-old male patient withprogressive metastatic carcinoma of the breast to the lungs, liver and bone.He was referred for radiotherapy because of generalized bony pains. Thepatient was planned for sequential hemi-body irradiation starting with themore symptomatic upper half body. After premedication, he was given 8.5 Gy tothe mid point at the maximum chest separation with anterior lung attenuatorlimiting uncorrected lung dose to 6.15 Gy. A further 3.5 Gy electron boost tothe fungating breast tumor was given to the 100%.Forty-eight hours after irradiation he developed hyperkalemia,hyperphosphatemia, hyperuricemia, hypocalcemia and renal failure. Theseclinical and biochemical changes are typical of tumor lysis syndrome (TLS).Despite hydration, and treating the hyperuricemia, the patient developed comaand died eight days after irradiation.The prophylaxis and management of TLS and in high-risk patients aredescribed to avoid this frequently fatal complication.     

Acute tumor lysis syndrome in solid tumors—a case report and review of the literature

PURPOSE: Tumor lysis syndrome (TLS) is a potential complication in cancer therapy. It may occur in highly sensitive tumors, especially in childhood cancers and acute leukemias, whereas it is rare in the treatment of adult solid tumors. TLS is characterized by hyperuricemia, hyperkalemia, hyperphosphatemia and hypocalcemia following massive lysis of malignant cells. Complications include acute renal failure and metabolic acidosis. We report the first case of TLS during chemotherapy in a patient with metastatic medulloblastoma, together with a review of the literature regarding the occurrence of TLS in patients with solid tumors. METHODS: Data regarding clinical and biochemical parameters were extracted from the actual patients' files. Reports of TLS in the English language literature up to 2002 were identified by searching Medline. RESULTS: A 23-year old male with metastatic medulloblastoma received chemotherapy with cisplatin and etoposide due to massive extracerebral manifestations including metastases to the liver, mediastinal lymph nodes and bone marrow metastases. The patient developed classical signs of TLS on the second day of chemotherapy, including acute renal failure. A 17-fold increase in plasma LDH up to 87608 U/l was observed together with a 4-fold increase in plasma creatinine. The patient was treated with aggressive hydration, allopurinol and repeated hemodialysis. During the following days the patient improved and the biochemical markers all returned to normal. REVIEW. Reviewing the literature, a total of 45 patients with solid tumors who developed TLS have been reported. Most of the patients presented with metastatic, therapy-sensitive disease. Although preventable in practically 100% of patients, TLS is a potentially fatal complication, and in this material the mortality rate was one in three. Risk factors included increased LDH, hyperuricemia and pretreatment azotemia. CONCLUSIONS: TLS is only rarely associated with treatment of solid tumors. Precautions should be taken to avoid this potentially fatal complication in (chemo)therapy of solid tumors, especially in therapy-sensitive tumors presenting with bulky, metastatic disease and preexisting risk factors, including azotemia, elevated LDH and hyperuricemia. Prophylactic treatment to avoid TLS includes allopurinol, hydration prior to treatment and alkalization of the urine. Urate oxidase (rasburicase) is now beginning to replace allopurinol as a more effective way of reducing hyperuricemia and thereby the risk of TLS.     

A single dose of rasburicase is sufficient for the treatment of hyperuricemia in patients receiving chemotherapy

Hydration, urinary alkalization, and allopurinol are the standard of care in the treatment and prevention of hyperuricemia. Rasburicase is a new alternative for the management of hyperuricemia in cancer patients. Criteria for the use of rasburicase were developed by the Hematology/Oncology Pharmacy and Therapeutics Subcommittee of the Detroit Medical Center and implemented in 2003. The guidelines limit rasburicase use to one dose, with additional doses as needed, compared to the five doses recommended by the manufacturer, in cancer patients with hyperuricemia and bulky tumor who require immediate chemotherapy. During the period of March to September 2003, eight patients received rasburicase, according to the guidelines, for the management of hyperuricemia. One dose of rasburicase produced a rapid and sustained therapeutic effect of lowering the plasma uric acid levels in all patients. The levels remained below 4 mg/dL throughout the administration of chemotherapy for up to 96 h. Utilizing the guidelines resulted in a significant cost savings of 100,000 US dollars.     

The Effective Control of Hyperuricemia in Cancer Patients: A New Recombinant Conjugated Variant of Urate Oxidase

Objective: Management of hyperuricemia is crucial to controlling tumor lysis syndrome (TLS) during cancer therapy. Urate oxidase (UOX) that catalyzes the enzymatic oxidation of uric acid into allantoin, is effective in lowering plasma uric acid levels and controlling hyperuricemia. Recently, we developed a new recombinant conjugate variant of UOX therapeutic drug using PASylation technology. This study was designed to evaluate the stability, plasma half-life and immunogencity of PASylated UOX. Methods: A recombinant variant of PASylated UOX from the Aspergillus flavus was manufactured using bioinformatics and experimental techniques. Ex vivo evaluation of stability of PASylated UOX was done in 50% human serum. For half-life test, recombinant PASylated UOX and rasburicase were administered at 1.5 mg/kg to 10 rats in two different groups and samples were collected after injection Production of antibodies against PASylated drug was also assayed. Results: Residual activity of PASylated UOX in 50% human serum was higher than rasburicase and native UOX. Stability of PASylated UOX at 25°C and 37°C was also higher than rasburicase and native UOX. The PASylated half-life was ~32.1 hours, whereas half-life for rasburicase and native UOX was ~25.1 and ~22.8 hours, respectively. In immunogenicity examination, there is 33% and 36% decrease in the absorbance of native UOX and rasburicase, respectively when compared with that of PASylated UOX. Conclusion: Our data confirmed the efficacy and stability of PASylated UOX in comparison to the rasburicase. In summary, the results indicated that PASylated UOX drug is effective at lowering plasma uric acid levels with prolonged plasma half-life and decreased cost.     

Tumour lysis syndrome in children: experience of last decade

The strategy against tumour lysis syndrome (TLS) had been hyperhydration, urine alkalinization, and allopurinol. Recently, rasburicase was added to the armament against this life-threatening condition. In Korea, rasburicase is used as a rescue therapy for cases with allopurinol-resistant hyperuricemia, because of the restriction by the National Health Insurance. We reviewed our experiences to re-assess the risk factors of TLS and the efficacy of rasburicase. Medical records were retrospectively reviewed for 396 children who were diagnosed as positive with acute leukemia and non-Hodgkin lymphoma between the years 2000 and 2009. The risk factors for TLS were analyzed statistically, and those before and after the availability of rasburicase were compared. Sixty eight patients (17.2%) had TLS. Multivariate analysis showed that pre-chemotherapy hypophosphatemia was a risk factor for TLS, in addition to the known risk factors of hyperuricemia and high lactate dehydrogenase concentration. The availability of rasburicase as a rescue therapy did not negate the importance of uric acid as a risk factor of TLS. Rasburicase as a second line treatment for intractable hyperuricemia was not effective in reducing the incidence of TLS. Pre-chemotherapy hypophosphatemia was a significant independent risk factor for TLS.     

Spontaneous tumor lysis syndrome in a patient with cholangiocarcinoma

Tumor lysis syndrome (TLS) is a potentially deadly complication of tumors or their treatment. This syndrome consists of a constellation of laboratory parameters such as hyperuricemia, hyperkalemia, hyperphosphatemia, and hypocalcemia and clinical complications such as seizures, acute renal insult, cardiac dysrhythmias and death. TLS is especially common in patients with hematological malignancies with rapid cellular turnover rates such as acute lymphocytic leukemia and Burkitt lymphoma, but is very rare in patients with solid tumors. However, it is essential to keep in mind that solid tumors can also lead to TLS. We present a case of a 66-year-old African American male with metastatic cholangiocarcinoma complicated by the development of spontaneous TLS. TLS has never been reported in a patient with cholangiocarcinoma.