Recognizing & Managing Cancer Emergencies

Most side effects of cancer treatment can wait until Monday. A small number cannot. In these situations, a delay of hours changes the outcome. The right move is to call the number your team gave you, or to go to an emergency department. Do not wait to see whether it settles.

This page is not here to frighten you. It is here so that if one of these happens, you recognize it quickly. And so that you act on it without apologizing for it.

If you are on cancer treatment, you should have been given a phone number answered around the clock. It is usually a triage line at your cancer center, or an on-call oncology service. If you do not have one, ask at your next visit. Then put it in your phone, on the fridge, and in your wallet.

Use it. These lines exist precisely for the calls people worry are "not serious enough." The nurses would far rather assess a false alarm than hear about a problem two days late.

At an emergency department, tell the front desk three things. That you are on cancer treatment. What your cancer is. And what treatment you had, and when. That sentence changes how quickly you are seen.

Many cancer treatments lower the white blood cells that fight infection. An ordinary infection can then turn dangerous fast. Fever may be the only sign you get. The usual redness, pus and swelling may never appear.

The threshold is around 100.4–100.5 °F (38 °C) or higher. Trusted sources word it a little differently. All of them describe the same body temperature:

• National Cancer Institute: a "fever of 100.5 °F (38 °C) or higher" — its printed 100.5 °F is a conversion slip, since 38 °C is 100.4 °F; act at 100.4 °F (38 °C) — listed as a sign of infection to report to your health care team.
• American Cancer Society: "For people with cancer, a fever is defined as a temperature of 100.4 °F (38 °C) or higher for at least one hour."
• MedlinePlus (NIH): a "fever of 100.4 °F (38 °C) or higher."
• The clinical definition of febrile neutropenia: "a single oral temperature greater than or equal to 101 F (38.3 C) or a temperature greater than or equal to 100.4 F (38 C) for at least an hour."

38.0 °C is exactly 100.4 °F. So NCI's 100.5 °F is a rounding of the same reading. ACS gives this advice: "ask your cancer care team what temperature they consider to be a fever. It might be different depending on your situation, but 100.4 °F (38 °C) is often used." Use the threshold your own team gave you. And if your temperature falls between these numbers and you are unsure, call anyway. No oncology service minds being called.

NCI states that infections during cancer treatment can be life threatening. They require urgent medical attention. NCI also warns that fever-reducing medicines can lower a temperature. But they may mask signs of a more serious problem. So ask your team before you take them.

Call without waiting if you have:

• Fever at or above your team's threshold, or shaking chills even without a measured fever
• New cough, breathlessness, sore throat, or burning when you pass urine
• Redness, swelling, pain or discharge around a catheter, port or wound
• Confusion, dizziness on standing, or suddenly feeling inexplicably unwell

Cancer in or near the spine can press on the spinal cord. Treated early, function is often preserved. Treated late, weakness and loss of bladder control can become permanent. That is why "I'll mention it at my appointment next week" is the wrong instinct here.

Watch for these warning signs:

• New or worsening back or neck pain, often worse lying flat or at night
• A band of pain around the chest or abdomen
• Weakness, heaviness or numbness in the legs or arms
• Unsteadiness on your feet
• Any new difficulty passing or controlling urine or stool

Bladder and bowel changes with back pain are a same-day emergency. The risk is higher for people with cancer that has spread to bone. See metastatic cancer.

Three other emergencies are worth knowing by name. They are easily mistaken for ordinary side effects.

Tumor lysis syndrome happens when a large number of cancer cells break down at once. It usually starts soon after treatment begins for fast-growing cancers, such as some leukemias and lymphomas. The contents released by those cells overwhelm the kidneys. Teams plan ahead for it with fluids, blood tests and preventive medicines. In the days after treatment begins, report reduced urine output, nausea and vomiting, muscle cramps or twitching, palpitations or unusual drowsiness.

High calcium in the blood (hypercalcemia) builds up slowly. It is often mistaken for the cancer itself, or for depression. Signs include heavy thirst, passing large amounts of urine, constipation, nausea, muscle weakness, and growing confusion or sleepiness. It is treatable. The confusion usually lifts once the calcium is corrected.

Superior vena cava obstruction happens when a tumor or clot blocks a large vein. That vein returns blood from the head and arms to the heart. Look for swelling of the face, neck or arms, distended veins across the chest, headache worse in the morning or leaning forward, a hoarse voice, and breathlessness. Breathlessness with facial swelling should be assessed the same day.

Not every worrying symptom is one of these. Most turn out to be something ordinary. But the cost of checking is an hour of your time. The cost of not checking can be much higher. Keep the 24-hour number where you can find it at 3 a.m. Tell whoever lives with you what these signs look like. And treat "something is wrong and I can't explain it" as reason enough to call. For symptoms that are troubling but not urgent, pain and symptom relief covers what to raise at a routine visit.

• National Cancer Institute — Infection and Neutropenia during Cancer Treatment
• MedlinePlus — Cancer treatment: preventing infection
• American Cancer Society — Fever and Infections
• StatPearls (NCBI Bookshelf) — Neutropenic Fever
• StatPearls (NCBI Bookshelf) — Spinal Cord Compression
• StatPearls (NCBI Bookshelf) — Tumor Lysis Syndrome
• StatPearls (NCBI Bookshelf) — Malignancy-Related Hypercalcemia
• StatPearls (NCBI Bookshelf) — Superior Vena Cava Syndrome