Oncologic Emergencies¶

Chapter 80 | Part 4: Oncology and Hematology · Part 4 – Oncology: Solid Tumors · Chapter 80

Key Clinical Points¶

Superior vena cava syndrome (SVCS) is the clinical manifestation of superior vena cava obstruction with severe reduction in venous return from the head, neck, and upper extremities.
Lung cancer, particularly of small-cell and squamous cell histologies, accounts for ~85% of all cases of malignant origin SVCS.
Malignant spinal cord compression (MSCC) occurs in 5–10% of patients with cancer; lung cancer is the most common cause.
Hyperleukocytosis and leukostasis syndrome occur when peripheral blast cell count is >100,000/mL in acute leukemia.
Dexamethasone is the best initial treatment for all symptomatic patients with brain metastases.
The 'hot quadrate' sign on CT scan suggests SVC obstruction caused by portosystemic venous shunting.
Erosion of the pedicles (the 'winking owl' sign) is the earliest radiologic finding of vertebral tumor in plain films.
Cauda equina syndrome is characterized by low back pain, diminished sensation over the buttocks, and rectal/bladder dysfunction.
Pericardial effusion containing malignant cells on cytology has a very poor survival prognosis.
Intestinal obstruction in patients with cancer has a poor prognosis with median survival of 3–4 months.

1. DEFINITION & OVERVIEW¶

Oncologic emergencies are classified into three groups:

• Structural-obstructive emergencies: e.g., SVCS, MSCC • Metabolic/hormonal complications: paraneoplastic syndromes • Treatment-related complications

Vaccination recommendations for cancer patients:

• Annual Vaccines: Influenza and COVID-19 vaccines are recommended for all patients. • Immune Response: Solid tumor patients generally mount stronger antibody responses than hematologic malignancy patients, even after B-cell-depleting therapies (e.g., rituximab). • Live Vaccines: MMR and varicella should be avoided in immunocompromised patients but may be administered to household contacts.

2. EPIDEMIOLOGY¶

SVCS epidemiology:

• Malignant causes: 60% (lung cancer ~85%, lymphoma 10–15%) • Benign causes: 40% (central venous catheters, fibrosing mediastinitis)

MSCC prevalence:

• Incidence: Occurs in 5–10% of cancer patients • Location: Thoracic spine most commonly affected (70%) • Common Primaries: Breast and prostate cancers frequently involve multiple spinal sites

Brain metastases:

• Mortality: 25% of cancer patients die with intracranial metastases • Primary Sources: Lung, breast, melanoma

3. ETIOLOGY & PATHOPHYSIOLOGY¶

SVCS mechanisms:

• Malignant obstruction: lung cancer, lymphoma • Benign causes: central venous catheters, fibrosing mediastinitis • Other: Behçet's syndrome may present with SVC thrombosis

MSCC pathophysiology:

• Mechanism: Extradural tumor compression of spinal cord/cauda equina • Primary tumors: lung, breast, prostate, multiple myeloma • Pathological processes: mechanical injury, ischemia, infarction

Leukostasis syndrome:

• Threshold: Blood viscosity increases at blast counts >100,000/mL • Mechanism: Leukemic cells invade endothelium causing hemorrhage • Common sites: brain, lungs

4. CLINICAL FEATURES¶

SVCS presentation:

• Symptoms: Facial swelling, dyspnea, cough, hoarseness • Physical signs: Dilated neck veins, collateral circulation, cyanosis • Severe cases: Proptosis and obtundation

MSCC symptoms:

• Early sign: Localized back pain (preceding neurologic deficits) • Radicular pain: ◦ Thoracic: bilateral band-like ◦ Cervical/lumbar: unilateral • Neurological signs: Lhermitte's sign, bowel/bladder dysfunction

Brain metastases:

• Symptoms: Headache, seizures, focal deficits • Hemorrhage: Common in melanoma/germ cell tumors • Hydrocephalus: Resulting from CSF obstruction

5. DIFFERENTIAL DIAGNOSIS¶

SVCS differentials:

• Malignancy: Lymphoma vs. germ cell tumor in young males • Benign causes: aortic aneurysm, thyromegaly, Behçet's syndrome

MSCC mimics:

• Spine issues: Osteoporotic fracture, disk disease, epidural hematoma • Other: Radiation myelopathy, neoplastic leptomeningitis

Brain metastases differentials:

• Vascular: Stroke-like presentation with hemorrhage • Drug-induced: Pseudotumor cerebri from tretinoin therapy

6. INVESTIGATIONS & DIAGNOSIS¶

SVCS Diagnosis:
Clinical diagnosis based on venous obstruction signs
Chest X-ray: Identify mediastinal widening (right side) and pleural effusion (present in 25%)
CT scan: Identify collateral venous channels and 'hot quadrate' sign
MRI: Highest sensitivity (100%) for SVC obstruction
MSCC Diagnosis:
MRI preferred for spinal cord visualization
T1/T2-weighted sequences to identify extradural masses
Gadolinium-enhanced MRI to delineate intramedullary disease
Plain films: Identify 'winking owl' sign (erosion of vertebral pedicles) as an early finding
Intestinal Obstruction Evaluation:
CT scan: Identify mass, prior surgery site, or abrupt transition zone
CT enteroclysis: Used for low-grade small bowel obstruction

6.1 Imaging Findings¶

• Chest radiograph: mediastinal widening (right side), pleural effusion • CT scan: collateral venous circulation, 'hot quadrate' sign • MRI: 100% sensitivity for SVC obstruction; visualizes spinal cord compression

Note: Neoplastic meningitis has a 40% false-negative rate with CSF cytology.

6.2 Diagnostic Criteria¶

• SVCS: Clinical signs + CT/MRI findings of venous obstruction • Neoplastic meningitis: Malignant cells in CSF + elevated protein • Intestinal obstruction: Mass at obstruction site, irregular bowel thickening

7. MANAGEMENT & TREATMENT¶

SVCS Treatment:
Immediate intervention for airway compromise (Oxygen, diuretics)
Endovascular stenting for malignant obstruction
Chemotherapy for lymphoma (e.g., CHOP regimen)
Radiation therapy for localized disease
MSCC Management:
Dexamethasone 16 mg/day for 4–5 days
Radiotherapy (20–35 Gy in 10–15 fractions)
Surgery for spinal instability (vertebroplasty/kyphoplasty)
Chemotherapy for systemic disease
Brain Metastases Treatment:
WBRT + dexamethasone (16 mg/day) for multiple lesions
SRS for 1–3 lesions (<3 cm)
Targeted therapy for EGFR-mutant NSCLC
Palliative care for poor performance status
Tumor Lysis Syndrome (TLS) Management:
Initial Treatment: Hydration (3000 mL/m² per day) + Allopurinol (800 mg/m² per day)
Evaluation at 24–48 hours: a. If Serum uric acid >8.0 mg/dL OR Serum creatinine >1.6 mg/dL → Correct treatable renal failure & start recombinant urate oxidase (0.2 mg/kg/d). i. If no improvement → Delay chemotherapy or start dialysis. b. If Serum uric acid <8.0 mg/dL AND Serum creatinine <1.6 mg/dL → Start chemotherapy with monitoring every 6–12 h.
Emergency Criteria (Any point): If K^+ >6.0 mg/L, Uric acid >10 mg/dL, Creatinine >10 mg/dL, Phosphate >10 mg/dL or increasing, OR Symptomatic hypercalcemia → Begin hemodialysis.

7.1 SVCS Treatment¶

• Immediate: Oxygen, diuretics for edema • Definitive: Endovascular stenting (malignant), Chemotherapy (lymphoma - e.g., CHOP), Radiation (localized)

7.2 MSCC Treatment¶

• Step 1: Dexamethasone 16 mg/day for 4–5 days • Step 2: Radiotherapy (20–35 Gy in 10–15 fractions) • Step 3: Surgery for spinal instability (vertebroplasty/kyphoplasty) • Step 4: Chemotherapy for systemic disease

7.3 Brain Metastases Treatment¶

• WBRT + dexamethasone (16 mg/day) for multiple lesions • SRS for 1–3 lesions (<3 cm) • Targeted therapy for EGFR-mutant NSCLC • Palliative care for poor performance status

7.4 Tumor Lysis Syndrome (TLS) Management¶

Initial Treatment: Hydration (3000 mL/m² per day) + Allopurinol (800 mg/m² per day)
Evaluation at 24–48 hours:
If Serum uric acid >8.0 mg/dL OR Serum creatinine >1.6 mg/dL → Correct treatable renal failure & start recombinant urate oxidase (0.2 mg/kg/d).
If no improvement → Delay chemotherapy or start dialysis.
If Serum uric acid <8.0 mg/dL AND Serum creatinine <1.6 mg/dL → Start chemotherapy with monitoring every 6–12 h.
Emergency Criteria (Any point):
If K^+ >6.0 mg/L, Uric acid >10 mg/dL, Creatinine >10 mg/dL, Phosphate >10 mg/dL or increasing, OR Symptomatic hypercalcemia → Begin hemodialysis.

8. PROGNOSIS & COMPLICATIONS¶

Prognostic factors:

• SVCS: 50% mortality within 6 months without treatment • MSCC: 20–30% mortality with timely intervention • Brain metastases: Median survival 4–6 months

Complications:

• SVC syndrome: Variceal bleeding, bilateral breast edema • MSCC: Paraplegia, autonomic dysfunction • Leukostasis: Respiratory failure, disseminated intravascular coagulation

9. SPECIAL CONSIDERATIONS¶

Vaccination guidelines:

• Live vaccines: Contraindicated in immunocompromised patients • Household contacts: Should receive MMR, varicella

Palliative care:

• Vertebroplasty for painful vertebral compression fractures • Symptom management for intestinal obstruction (parenteral nutrition) • Intrathecal chemotherapy for neoplastic meningitis

10. KEY PEARLS & CLINICAL TRAPS¶

Critical pearls:

• 'Hot quadrate' sign on CT indicates portosystemic shunting in SVC obstruction • Lhermitte's sign is an early indicator of spinal cord compression • Dexamethasone is first-line for brain metastases and MSCC

Common pitfalls:

• Delayed diagnosis of MSCC leading to irreversible neurologic damage • Misinterpreting pleural effusion as the sole finding in SVCS • Overlooking neoplastic meningitis with negative CSF cytology