Oncology - Oncological Emergencies

• Oncological emergencies lead to the need for emergent evaluation and treatment in cancer patients because of unique complications.
• An oncological emergency is an acute condition caused by cancer or its treatment, requiring immediate intervention to avoid mortality or severe morbidity.

Types of Oncological Emergencies

• Cardiovascular emergencies include pericardial tamponade and superior vena cava (SVC) syndrome.
• Neurologic emergencies include brain metastasis, increased intracranial pressure, and spinal cord compression (SCC).
• Gastrointestinal emergencies include bowel obstruction and bowel perforation.
• Hematological emergencies include disseminated intravascular coagulation (DIC), leukostasis, and thrombocytopenia.
• Respiratory emergencies include airway obstruction and pneumothorax.
• Renal emergencies include ureteral obstruction and pelvic tumors.
• An orthopedic emergency is a pathologic fracture.
• Metabolic emergencies include hypercalcemia, hypoglycemia, lactic acidosis, and tumor lysis syndrome.
• Infectious emergencies include sepsis and neutropenic fever.

Superior Vena Cava (SVC) Syndrome

• Defined as venous congestion of the head, neck, and upper extremities due to impaired venous flow through the superior vena cava to the right atrium.
• Etiology of SVC syndrome is classified into malignant, which accounts for over 90% of cases or benign causes.
• Lung cancer, lymphoma and metastatic disease are common malignancies found with SVC syndrome.
• Mediastinal tumors account for less than 2% of SVC syndrome cases.
• SVC syndrome pathophysiology involves blood flow obstruction through the SVC due to external compression or internal occlusion.
• SVC obstruction impairs venous drainage from the head, neck, upper extremities, and thorax, reducing venous return to the heart.
• SVC obstruction results in decreased cardiac output, increased venous congestion, and edema.
• Severity of symptoms in SVC syndrome depends on the obstruction acuity and the compromise of SVC flow.
• Gradual progression of SVC syndrome allows for the development of collateral circulation in the azygous venous system.
• This gradual progression leads to a more benign presentation.
• Periorbital edema, facial edema, arm edema, venous distention of chest wall and congested non-pulsating neck veins are characteristic physical examination findings of SVC syndrome.
• Diagnosis of SVC syndrome is reached when around 60% of patients present without a prior cancer diagnosis.
• A histologic diagnosis is required before starting antitumor therapy if imaging studies suggest malignancy.
• The CT chest is the most useful study for imaging the mediastinum and a biopsy should be obtained for a first presentation.
• Emergency radiation therapy is no longer considered necessary for managing most SVC patients.
• Accurate histologic diagnosis before starting therapy is important.
• Use upfront endovenous therapy (e.g., stenting) in patients with severe symptoms for rapid symptom relief instead of radiation therapy alone.
• Steroid-responsive malignancies like lymphoma or thymoma can respond to glucocorticoids in reversing symptomatic SVC syndrome.
• If lymphoma is suspected but not yet histologically confirmed, glucocorticoids may obscure the diagnosis due to their lympholytic effects.
• Initial chemotherapy is the treatment of choice for chemotherapy-sensitive malignancies
• For radio-sensitive tumors (less chemotherapy-sensitive, no prior RT), radiotherapy is widely advocated for SVC syndrome.

Brain Metastasis and Increased Intracranial Pressure

• Raised intracranial pressure results from the space-occupying effect of intracranial tumors, most often metastatic.
• Lung cancer, melanoma, renal cell carcinoma, and breast cancer are the most common primary tumors that metastasize to the brain.
• Any new neurologic symptom in a cancer patient requires consideration of metastasis diagnosis.
• An exceptions occurs when other possible causes are more likely.
• CT scans of the brain can detect most brain metastases.
• MRI of the brain has greater sensitivity for detecting any small metastases, meningeal disease, and fourth ventricle obstruction.
• A biopsy may be necessary for diagnosis in patients with a single intracranial lesion, especially if there is minimal systemic disease or only a remote cancer history.
• Patients without a prior cancer history should have efforts made to get a histological diagnosis, especially if a single brain tumor is present.
• A biopsy may not be appropriate for frail patients with multiple cerebral metastases and potential other sites of metastatic disease.
• Initial management includes using corticosteroids such as dexamethasone and covering with a proton pump inhibitor.
• In severe cases with rapidly falling Glasgow Coma Score, administer IV mannitol.
• Avoid fluid overload.
• Surgical resection or stereotactic radiosurgery (SRS) is recommended over whole-brain radiation therapy (WBRT) alone for single brain metastasis.
• Large, symptomatic tumors, tumors with extensive edema and cases with diagnostic uncertainty typically indicate surgical resection.
• SRS is suitable as an alternative to surgery for small or inaccessible single tumors.
• SRS (stereotactic radiosurgery) gives a single, highly concentrated dose of ionizing radiation to a small target.
• SRS is favored for few brain metastases over WBRT alone.
• Although WBRT improves intracranial disease control, it doesn't improve overall survival and may reduce quality of life.
• WBRT remains the mainstay for patients with good performance status with multiple brain metastases who are ineligible for SRS/surgery or lack effective systemic therapy options.

Spinal Cord Compression (SCC)

• Spinal cord compression is an oncologic emergency as delays in diagnosis can cause irreversible neurologic compromise and functional decline.
• The most common cancers associated with malignant spinal cord compression are breast, prostate, lung, multiple myeloma, and lymphoma.
• The common presenting symptom is back pain in cases of malignant SCC.
• Other symptoms and signs depend on compression level, including paraparesis, paralysis, loss of sensation, and urinary/fecal incontinence.
• Muscle weakness often occurs before sensory loss or autonomic dysfunction.
• MRI with contrast of the spine is the most sensitive diagnostic test to detect compression level.
• Multiple levels of compression may be found.
• Establish a tissue diagnosis if possible through a needle biopsy in patients without a prior cancer diagnosis.
• Primary treatment goals include pain control, preservation/recovery of neurologic function and prevention of complications.
• Immediate interventions include starting corticosteroids (dexamethasone) and consulting neurosurgery/radiation oncology.
• Further therapy depends on the clinical picture, spinal stability, the availability of histologic diagnosis, and previous treatment.
• Spinal instability (even without clinical signs or symptoms) dictates surgery.
• Hematologic tumors indicate radiation therapy as an appropriate treatment modality.
• Life expectancy of <3-6 months and paraplegia present for >24 hours are contraindications for radiation therapy.
• Systemic Chemotherapy is an appropriate primary treatment modality only for patients with SCC caused by highly chemosensitive tumors.