In this post, I link to and review The Curbsiders‘ #358 Oncologic Emergencies with Dr. Aditi Singh, 1:24:22, OCTOBER 3, 2022 By MATTHEW WATTO, MD.*
*Trubitt MT, Amin MA, Singh, A. “#358 Oncologic Emergencies”. The Curbsiders Internal Medicine Podcast. https://thecurbsiders.com/episode-list October 3rd, 2022.
All that follows is from the above resource.
Do you freak out over oncologic emergencies like cord compression or tumor lysis syndrome? Join Dr. Aditi Singh (University of Pennsylvania, Abramson Cancer Center, @AditiSinghMD) for this comprehensive conversation on six commonly encountered oncologic emergencies we see in the hospital!
Oncologic Emergencies Pearls
- Do not wait for permission to order steroids for cord compression.
- The most common presenting symptom of cord compression is back pain, and it may not present with the classic triad of cauda equina syndrome.
- Malignant SVC syndrome can be associated with thrombus, which requires treatment with anticoagulation.
- Malignant bowel obstruction or pseudo-obstruction may be due to other risk factors besides current cancer diagnosis such as pain medications (e.g. opioids), prior surgeries, prior pelvic radiation, or current cancer-specific treatment.
- Elevated calcium levels may be an early sign of cancer recurrence for some cancer types, most commonly breast, lung, and multiple myeloma..
- Cairo-Bishop criteria can be used for diagnosis of lab-based or clinical tumor lysis syndrome.
- For patients with hypocalcemia in tumor lysis syndrome, treat with a phosphorus binder, because the mechanism of hypocalcemia is elevated serum phosphorus which binds calcium. Calcium repletion may result in precipitation of calcium phosphate in renal tubules resulting in acute kidney injury.
- For patients who present with hyperleukocytosis, be cognizant of leukostasis as a potentially fatal complication.
Oncologic Emergencies Pearls
- Do not wait for permission to order steroids for cord compression.
- The most common presenting symptom of cord compression is back pain, and it may not present with the classic triad of cauda equina syndrome.
- Malignant SVC syndrome can be associated with thrombus, which requires treatment with anticoagulation.
- Malignant bowel obstruction or pseudo-obstruction may be due to other risk factors besides current cancer diagnosis such as pain medications (e.g. opioids), prior surgeries, prior pelvic radiation, or current cancer-specific treatment.
- Elevated calcium levels may be an early sign of cancer recurrence for some cancer types, most commonly breast, lung, and multiple myeloma..
- Cairo-Bishop criteria can be used for diagnosis of lab-based or clinical tumor lysis syndrome.
- For patients with hypocalcemia in tumor lysis syndrome, treat with a phosphorus binder, because the mechanism of hypocalcemia is elevated serum phosphorus which binds calcium. Calcium repletion may result in precipitation of calcium phosphate in renal tubules resulting in acute kidney injury.
- For patients who present with hyperleukocytosis, be cognizant of leukostasis as a potentially fatal complication.
Treatment
As soon as you get the call for admission, Dr. Singh says not to hesitate to order an initial steroid dose (typically dexamethasone 10 mg, followed by 4 mg every 6 hours). Ultimately, the specialists should provide the duration and taper for steroids. Length of steroid treatment is dependent on length of radiation therapy, type of cancer, and surgical plan, so should be determined by the multidisciplinary team (expert opinion).
The multidisciplinary team will consist of neurosurgery (or local spine surgery team) and radiation oncology. The patient’s surgical candidacy is up to the surgeon, but Dr. Singh provided the mnemonic NOMS (Neurologic, Oncologic, Mechanical, Systemic) that the surgeon may use to determine candidacy (Laufer, 2013).
- Neurologic: What are the neurologic deficits present?
- Oncologic: Where is the patient in their cancer journey? Is the cancer type chemo or radiosensitive as an additional therapeutic option?
- Mechanical: How stable is the spine, and can surgery safely be done?
- Systemic: What is the patient’s overall health status and can they tolerate surgery?
Premorbid functional status is an important factor for overall functional prognosis, and explains the reason for quick action (Lawton, 2019).
SVC Syndrome
Diagnosis
SVC syndrome is caused by compression of the superior vena cava and the hallmark finding is facial edema (Higdon, 2018). SVC syndrome is a clinical diagnosis and other signs/symptoms may be present as well including distended neck veins, cough, dyspnea, orthopnea, upper extremity swelling, distended chest vein collaterals, and/or conjunctival suffusion. Less commonly SVC syndrome can present with stridor, hoarseness, dysphagia, pleural effusion, head plethora, headache, nausea, lightheadedness, syncope, change in vision, altered mental status, upper body edema, cyanosis, papilledema, stupor, and/or coma (Seligson, 2022).
While diagnosis of SVC syndrome is clinical, it is important to confirm with a CT scan of the neck with IV contrast. If the patient cannot tolerate contrast, then order MR venography instead. The imaging can help discern location, severity, and etiology to help guide treatment options and timing (Seligson, 2022).
The cancers most predisposed to SVC syndrome include lung, non-Hodgkin lymphoma, thymic, germ cell, breast, and mesothelioma.
Treatment
The first step to treatment is to ensure stability of the patient (e.g. evaluate airway and breathing).. The next steps are involving the multidisciplinary team which will include vascular surgery for possible endovascular stenting to alleviate the obstruction (Higdon, 2018) as well as radiation oncology.
Additionally, Dr. Singh recommends additional oncologic evaluation to consider chemotherapy and/or radiation depending on tumor sensitivity. This could be complicated if SVC syndrome is the presenting symptom of a new cancer diagnosis, as it is necessary to get a histologic diagnosis first to initiate appropriate cancer-directed treatment.
Lastly, if SVC syndrome is found with an associated thrombus, the team will need to consider anticoagulation. Depending on other procedures needed (i.e. endovascular intervention), catheter-directed thrombolysis may be a possible treatment modality (Seligson, 2022).
Malignant Obstruction
Diagnosis
The most common associated symptoms include: nausea, vomiting, colicky abdominal pain, and the absence of flatus or stool in the last 72 hours (Ferguson, 2015). Dr. Singh urges us to remember that even if someone has an underlying cancer, their obstruction may not be due to the malignancy but other risk factors such as prior surgery, prior pelvic radiation, opioids or cancer-specific treatment causing pseudo-obstruction.
Cancers most commonly associated with malignant obstruction include colorectal, ovarian, peritoneal metastasis, and melanoma.
If there is a high suspicion for obstruction or even with confirmed obstruction on abdominal x-ray, it is important to get a CT abdomen/pelvis with contrast to provide more information about the transition point, partial vs complete obstruction, and high or low grade obstruction, as these answers all impact surgical decision-making (expert opinion).
As with all oncologic emergencies, the primary team needs to involve the multidisciplinary team managing this patient, including medical oncology, general surgery, and palliative care.
Treatment
Initial therapies include conservative management of IV fluids, NPO, NG tube for decompression, electrolyte repletion as well as symptom control for both pain and nausea. Considerations for symptomatic control include somatostatin analogues which decrease secretions and motility, scopolamine, and steroids (Ferguson, 2015).
Nutrition is often a central concern, particularly for the patient and their family. Therefore, total parenteral nutrition (TPN) may come up in family discussions. Dr. Singh notes that while this is an available treatment modality, it is very dependent on where the patient is in their cancer journey. If the underlying malignancy cannot be treated, then starting TPN may prolong longevity without improving quality, thereby requiring a multidisciplinary discussion with the patient’s primary oncologist and likely palliative care provider.
Lastly, Dr. Singh highlights that malignant obstruction often results in recurrent admissions and a venting G-tube may be considered as a palliative measure.
Hypercalcemia of Malignancy
For a full review of hypercalcemia, please refer to episode 281.
Dr. Singh had a couple of pearls she wanted to highlight regarding hypercalcemia in the setting of malignancy. First, the most common associated cancers with this condition are squamous cell cancer from the lung or head and neck, which is mediated by parathyroid related protein (PTHrP). It is also associated with multiple myeloma due to lytic lesions and lymphoma due to activation of vitamin D.
The ultimate treatment for hypercalcemia of malignancy is treating the underlying cancer, but the initial mainstay of therapy is fluids. A newly uptrending calcium may be the first sign that there is recurrence of malignancy.
fig2 when server ready!
Tumor Lysis Syndrome
Pathophysiology
Tumor lysis syndrome can occur spontaneously or after initiating therapy. When it occurs spontaneously, the tumor is outgrowing its blood supply resulting in lysis of tumor cells. When it occurs after initiating therapy, the cell death is intentional, but still results in lysis of tumor cells (Howard, 2018). As Dr. Singh says, whatever is inside the cell comes out when the cell dies which includes potassium, phosphorus, and uric acid. The increasing serum phosphorus then binds to calcium ions which drives calcium levels down, which can lead to dangerous hypocalcemia.
Diagnostic Criteria
Cairo-Bishop Criteria defines tumor lysis syndrome (Howard, 2018).
Laboratory tumor lysis syndrome: requires two of the below serologic criteria within the same 24 hour period either 3 days before starting therapy or up to 7 days afterward:
- Potassium > 6 mmol/L
- Phosphorus > 4.5 mg/dL
- Uric acid > 8 mg/dL
- Corrected Calcium < 7 mg/dL
Clinical tumor lysis syndrome: requires meeting laboratory tumor lysis syndrome criteria (listed above) PLUS one of the following:
- Acute kidney injury
- Seizures
- Cardiac dysrhythmia
- Death
Dr. Singh reminds us that while we often obtain LDH levels, this is not part of the criteria for TLS diagnosis. LDH is a marker of high cell turnover and suggests risk of TLS however it should not be used to monitor for TLS by itself.
Common cancers at high risk for TLS are high-turnover hematologic malignancies such as: Burkitt’s lymphoma, diffuse large B cell lymphoma, ALL, CLL (especially with an elevated WBC#). TLS can be seen rarely with some solid tumor malignancies such as small cell lung cancer or colorectal cancer.
Treatment
Management is aimed at preserving renal function. Dr. Singh recommends that treatment to avoid renal failure should include high rate maintenance intravenous fluids such as 150-250 cc/hr.
Additionally, treatment is aimed at carefully managing electrolytes, Dr. Singh warns against the common pitfall of repleting hypocalcemia, as this may result in more precipitation of bound calcium and phosphorus, which can worsen acute kidney injury. She reminds us that phosphorus binders should be the mainstay of treatment as they treat both the phosphorus and calcium abnormalities.*
*See Hyperphosphatemia Medication from emedicine.medscape.com
Updated: Aug 19, 2022
Author: Eleanor Lederer, MD, FASN
