Fever when the immune system is down
Many chemotherapy drugs temporarily lower the number of neutrophils, the white blood cells that fight bacteria. A fever during this period, called febrile neutropenia, can be the first sign of a serious infection and is treated as a medical emergency. Yet many patients recover without complications. In 2000, a team led by Jean Klastersky for the Multinational Association for Supportive Care in Cancer (MASCC) published a score to identify these low-risk patients, who may be safely treated with less intensive care.
The items
| Characteristic | Points |
|---|---|
| Burden of illness: no or mild symptoms | 5 |
| Burden of illness: moderate symptoms | 3 |
| No low blood pressure (systolic above 90 mmHg) | 5 |
| No chronic obstructive pulmonary disease | 4 |
| Solid tumor, or blood cancer with no previous fungal infection | 4 |
| No dehydration needing IV fluids | 3 |
| Outpatient when the fever started | 3 |
| Age under 60 | 2 |
The maximum is 26. The “burden of illness” item reflects how unwell the patient seems overall, as judged by the clinician.
Interpreting the score
- 21 or more: low risk. In the validation study, about 91% of these patients recovered without serious complications.
- Below 21: high risk. Patients are admitted for intravenous broad-spectrum antibiotics and close monitoring.
Worked example
A 64-year-old outpatient receiving chemotherapy for breast cancer develops a fever. She has mild symptoms (5), normal blood pressure (5), no COPD (4), a solid tumor (4), no dehydration (3) and was at home when the fever began (3). Her age gives no points. The score is 24, in the low-risk group.
What a low-risk score allows
Guidelines from the American Society of Clinical Oncology and the Infectious Diseases Society of America suggest that selected low-risk patients can receive oral antibiotics, often after a few hours of observation, and be managed as outpatients if they:
- can take tablets and have no nausea or vomiting,
- live close to the hospital with a caregiver and a phone,
- can return immediately if they get worse.
The score supports clinical judgment and never replaces it. Some patients with a high score still need admission because of other factors.
For patients
A temperature of 100.4 °F (38 °C) or higher during chemotherapy needs urgent assessment, day or night. Do not take fever-reducing drugs before calling, because they can hide the fever. Keep your oncology team’s emergency number at hand.
This calculator is for general information and education. It is not medical advice and does not replace the judgment of a doctor, nurse or pharmacist who knows the full clinical picture.