Cancer Care

Why fevers should be taken seriously in cancer patients

May 31, 2023 Word for Word Media 0Comment

Dr Sarita Retief explains why fevers are emergencies in cancer patients and explains the four probable causes.

You can listen to this article below, or by using your favourite podcast player at

Fevers are a common and worrisome symptom in cancer patients. Causes can broadly be divided in four categories:

  1. Infections during immune suppression after chemotherapy.
  2. Other incidental infections.
  3. Paraneoplastic fever.
  4. Treatment-related fever.

A fever is an emergency

As an oncologist in training, one of the first lessons you learn, is that fever in an oncology patient, most of the times, constitutes an emergency. This is especially true if the patient had chemotherapy within the last six weeks, and even more so with any blood cancer or lymphoma.  

Fever would be defined as a temperature more than 38°C for more than an hour, or any temperature more than 38.3°C.

Fever after chemotherapy

When getting chemotherapy, your oncologist will always inform you to immediately contact the emergency line if you have fever. You should never wait until the next day, or till Monday on a weekend.

When arriving at casualty, vitals will be taken to determine if you’re in septic shock or not. A source of infection will be searched for, that means collecting blood, urine and sputum for cultures and taking a chest X-ray. 

On the full blood count, the neutrophil count (white cells that fight bacterial infections) will also be determined. If the neutrophils are less than 1000, it’s called neutropenia; less than 500 is severe neutropenia, and less than 100 is profound neutropenia. The lower the count, the lower your defence against especially atypical bacterial infections. 

Treating a fever

Within 30 to 60 minutes after presenting with fever, you must have the first dose of broad-spectrum antibiotics. You will then be admitted for at least five days of intravenous antibiotics. 

During admission, adequate fluids will be given to ensure good urinary output as low blood pressure and renal failure are serious consequences of bacterial infections.  

If treated promptly, this complication shouldn’t cause any threat. But if left untreated for too long, there is a risk of septicaemia.

Other incidental infections

Of course not all episodes of fever are related to low white cells and infection. Sometimes patients get fever because of other incidental infections, like malaria, tick bite fever and TB. It’s therefore important to tell the doctor if you travelled anywhere. Other infections are then treated accordingly. 

Paraneoplastic fever

Some cancers themselves can also cause fever (called a paraneoplastic syndrome). This is usually caused by lymphomas, blood cancers, renal and liver cancer. These tumours produce cytokines that stimulate the hypothalamus and cause fever. Sometimes people can present with fever even before they know that they have cancer. Fever will get better if the cancer is treated. 

Treatment-related fever

Sometimes fever can be treatment related. Blood transfusions, some antibiotics, some chemotherapy drugs, and biological treatment can cause fever. The causative drugs should be avoided or if it can’t be discontinued, then fevers must be treated symptomatically with paracetamol. 

Inform your oncologist immediately

The most important take-home message is, to inform your oncologist immediately if you have any fever. With your personal history of cancer and treatment, they will then decide how serious it is and if you need immediate treatment. 

Dr Sarita Retief

MEET THE EXPERT – Dr Sarita Retief

Dr Sarita Retief is currently working as a clinical and radiation oncologist at Nelspruit Mediclinic in the private sector. She completed pre- and postgraduate studies at the University of the Free State.

Image by