TABLE 95-1 Common Symptoms and Signs of Superior Vena Cava Syndrome | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Oncologic Emergencies
Oncologic Emergencies
Diane M.F. Savarese
I. SUPERIOR VENA CAVA (SVC) SYNDROME
A. Etiology.
1. SVC syndrome results from obstruction of venous return.
a. Invasion of tumor into SVC or intravascular thrombus.
b. External compression of the SVC.
2. Sixty-five percent to eighty percent of cases due to malignancy.
a. Predominantly lung cancer and lymphoma.
3. Other causes.
a. Thrombosis (usually with an indwelling intravascular device).
b. Mediastinal fibrosis.
B. Clinical features and diagnosis.
1. Symptoms and signs of SVC syndrome (Table 95-1) are related to the following:
a. Poor venous return.
b. Increased intravenous (IV) pressure.
c. Collateral vessel engorgement.
2. Radiographic studies are usually diagnostic.
a. Chest radiograph abnormal in >80%: mediastinal widening, pleural effusion.
b. Contrast-enhanced chest computed tomography (CT) the preferred diagnostic study.
i. Identifies the site of venous obstruction.
ii. Suggests etiology and identifies impending complications.
c. Upper extremity venography.
i. Gold standard for defining the level and extent of SVC obstruction.
ii. Cannot identify etiology unless thrombosis is the sole cause.
3. Tissue diagnosis: Routine diagnostic procedures carry little excess risk.
a. Pursue the least invasive option.
i. Sputum or pleural fluid cytology.
ii. Biopsy of an enlarged peripheral lymph node.
iii. Transthoracic CT-guided biopsy.
iv. Bronchoscopy with biopsy.
b. Pursue more invasive procedure if necessary to establish diagnosis.
i. Mediastinoscopy.
ii. Video-assisted thoracoscopy.
iii. Thoracotomy.
c. Emergent treatment before pursuing histologic diagnosis required if the following are present:
i. Stridor.
ii. Confusion, obtundation.
iii. Hemodynamic compromise.
C. Treatment.
1. Goals: Alleviate symptoms; treat underlying cause.
a. Urgency of treatment depends on severity of SVC syndrome (Yu, 2008). In the presence of the following severe life-threatening symptoms, perform immediate venogram and urgent endovascular stenting for rapid relief of symptoms; direct thrombolysis if thrombus present:
i. Stridor.
ii. Confusion, obtundation.
iii. Hemodynamic compromise.
b. After urgent management of severe or life-threatening symptoms, and for all others, establish the histologic diagnosis and tumor stage to select appropriate therapy for malignancy-associated SVC syndrome.
2. Definitive therapy depends upon underlying etiology.
a. Malignant cause: Histology and tumor stage dictate initial antitumor treatment.
i. Surgery for selected cases (nonmetastatic thymoma, residual germ cell cancer).
ii. For nonsurgically managed malignancy, chemotherapy is preferred for chemosensitive tumors (lymphoma, mediastinal germ cell tumor, small cell lung cancer).
iii. Intraluminal stenting.
(a) Useful for extrinsic tumor compression.
(b) Provides more rapid relief of symptoms in more patients than radiation therapy (RT).
(c) Does not compromise ability to establish a histologic diagnosis.
iv. Radiation therapy.
(a) Relieves symptoms, though not as quickly as stenting.
b. Nonmalignant causes.
i. Intravascular device associated.
(a) Remove device, if possible.
(b) Consider thrombolysis if thrombus ≤5 days old.
ii. Mediastinal fibrosis.
(a) Benefits of stenting are generally short lived.
(b) Surgical bypass may be required.
3. Supportive care.
a. Bed rest with head elevated to reduce central venous pressures.
b. Diuretics (avoid depletion of intravascular volume), decreased salt intake.
c. Oxygen.
4. Glucocorticoids.
a. Most useful in lymphoma and thymoma (cytolytic effect).
b. Short course of high-dose glucocorticoids may be recommended with emergent RT for impending airway obstruction.
i. Minimizes edema.
ii. Reduces the risk of central airway obstruction.
II. TUMOR LYSIS SYNDROME (TLS)
A. Pathophysiology.
1. Massive cytolysis of malignant cells releases large amounts of potassium, phosphate, and uric acid with secondary hypocalcemia.
2. Acute renal failure from precipitation of uric acid and/or calcium phosphate in the renal tubules.
B. Etiology.
1. Most commonly encountered after initial chemotherapy for the following:
a. Clinically aggressive non-Hodgkin lymphomas (NHL, particularly the Burkitt and lymphoblastic subtypes).
b. Acute lymphoblastic leukemia (ALL).
2. May also occur spontaneously in high-grade NHL or ALL.
3. May occur in other tumor types with a high proliferative rate, large tumor burden, or high sensitivity to cytotoxic therapy.
C. Diagnosis.
1. Cairo-Bishop definition (Table 95-2).
D. Prevention and treatment.
1. Best management is prophylaxis. Risk stratification guidelines are available (Cairo et al., 2010).
2. Prevention.
