Oncologic Emergencies (Including Hypercalcemia)

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Chapter 57 Oncologic Emergencies (Including Hypercalcemia)

Marie E. Wood, MD

1 Define oncologic emergency

A unique set of complications associated with patients with cancer requiring emergent evaluation and treatment.

2 List the four types of oncologic emergencies, and give examples of each

Metabolic: Tumor lysis syndrome, hypercalcemia, syndrome of inappropriate antidiuretic hormone, lactic acidosis

Structural or mechanical: Spinal cord compression, superior vena cava (SVC) syndrome, malignant pericardial effusion

Hematologic: Neutropenic fever, leukostasis, disseminated intravascular coagulation, thrombosis, hyperviscosity

Side effects of chemotherapy: Extravasation, hemorrhagic cystitis, typhlitis

Metabolic emergencies

3 What are the symptoms of hypercalcemia?

Symptoms can be vague but most classically include lethargy, confusion, anorexia, nausea, constipation, polyuria, and polydipsia. Hypercalcemia occurs in 10% to 30% of individuals with advanced or metastatic cancer.

4 What are the important treatments for hypercalcemia?

Hydration: Use normal saline solution, watching for congestive heart failure.

Bisphosphonate therapy: The most common choices of therapy include either pamidronate 60 to 90 mg intravenously (IV) over a 2- to 4-hour period or zoledronic acid 4 mg IV over a 15-minute period (the latter must be adjusted for renal insufficiency).

Stop medications that contribute to hypercalcemia: calcium, vitamin D, thiazide diuretics.

5 Discuss reasons for not using furosemide (Lasix), calcitonin glucocorticoids, and other older therapies

The easy answer is that bisphosphonates work much better. However, furosemide can be helpful but only if the patient is hydrated. Calcitonin works but only for a short time. Glucocorticoids are really only a temporizing measure.

6 Which patients with cancer are at risk for lactic acidosis?

Lactic acidosis is a rare complication of malignancy and is seen in patients who have cancer with a high proliferative rate such as lymphoma, leukemia, and small cell carcinoma.

7 How does lactic acidosis present, and how should it be treated?

Common symptoms include tachypnea, tachycardia, abdominal pain, and hepatomegaly. Mortality is very high and institution of chemotherapy the most effective treatment.

8 Can tumor lysis syndrome be prevented?

Absolutely yes, with early initiation of allopurinol or rasburicase, close monitoring of laboratory values, and aggressive hydration.

9 Which patients are at risk for tumor lysis syndrome?

Patients with large tumor burden and tumors with a high proliferative rate that are highly sensitive to chemotherapy (acute myelogenous leukemia, acute lymphocytic leukemia, Burkitt lymphoma, multiple myeloma, small cell carcinoma) are at risk for tumor lysis. Dehydration, renal insufficiency or obstruction, or elevated lactate dehydrogenase (LDH) or uric acid level before initiation of chemotherapy may increase the risk for complications from tumor lysis.

10 Can tumor lysis happen before administering therapy?

Yes, tumor lysis can be seen in very actively growing tumors with a high proliferative rate.

11 Discuss the features of tumor lysis syndrome

Tumor lysis is caused by release of cell contents into the bloodstream. Therefore patients have elevated levels of LDH, uric acid, potassium, urea nitrogen, creatinine, and phosphate, and low calcium.

12 How should tumor lysis be treated?

Patients at risk should start taking allopurinol (300-600 mg/day for 2 days) and be aggressively hydrated before initiation of chemotherapy. If tumor lysis develops despite these measures patients should have alkalinization of urine with forced diuresis with furosemide and frequent monitoring of urine volume, cardiac and volume status, and laboratory values (blood urea nitrogen, creatinine, uric acid, calcium, phosphate, and potassium levels).

13 When should rasburicase be used?

Rasburicase promotes the degradation of uric acid whereas allopurinol decreases the formation of uric acid. One study shows improved control of uric acid compared with allopurinol. Rasburicase can be considered in patients with very high uric acid level in need of urgent treatment.

Structural emergencies

14 What is the single most important predictor of functional status for a patient with cord compression?

The neurologic status at presentation predicts functional status after treatment. Patients presenting with pain only are far more likely to be ambulatory after treatment than patients presenting with neurologic dysfunction.

15 Because back pain is common, how can you distinguish pain due to cord compression from other back pain?

The cardinal features of cord compression include pain that worsens when supine and that can be reproduced with vertebral percussion. Additional findings of cord compression include constipation and incontinence (usually due to overflow incontinence) and sensory loss.

16 Should a patient with suspected cord compression receive steroids before imaging studies?

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