Confusion and Cancer: What You Need to Know

Confusion can be a troubling side effect for people dealing with brain tumors, and it can cause people who have not been diagnosed with a brain tumor to wonder whether it is indicative of a larger medical issue.

While not every patient with a brain tumor will experience confusion, some patients may experience delirium throughout their treatment, depending on the part of the brain where the tumor is located. Here’s what you should know about confusion—when it’s a symptom or side effect of a brain tumor, when it’s not, and what you can do to mitigate the problem.


Confusion and delirium are not always caused by a brain tumor

For most people, confusion has medical causes that are unrelated to a brain tumor. Infections, dehydration, or abnormalities in blood counts or metabolic factors, can all cause confusion for people without a brain tumor.

For people who have already received a diagnosis of a brain tumor, these issues can be a result of treatment, and can cause confusion that is not related to the tumor itself.

Proper hydration, sufficient sleep, and eating healthy can help alleviate or prevent confusion for people with and without a brain tumor. However, if the issue persists, it is a good idea to see a doctor to find out what is causing the confused state.

Treatments for the brain tumor can change the patient’s experience with confusion

Some patients with brain tumors will not experience confusion until they begin treatment. Treatments for brain tumors, such as radiation therapy, surgery and chemotherapy, can cause swelling in the brain, which can cause or exacerbate confusion. Additionally, some treatments may affect the immune system, which puts patients at a higher risk of infection. Urinary tract infections, GI illness, low blood count levels and changes to kidney or liver function may result from treatment, and can cause confusion unrelated to the tumor.

Increased confusion does not mean that treatment has failed or that the tumor has gotten worse

Many patients with brain tumors worry that new or worsened confusion means that the treatment for their brain tumor is not working. This is not always the case, says Ugonma Chukwueke, MD, a neuro-oncologist in the Center for Neuro-Oncology at Dana-Farber Cancer Institute.

“We consider the whole picture,” Chukwueke says. “Has the patient had a recent surgery? Are they dealing with any infections or issues with their blood counts? Is there swelling in the brain? Is there a history of seizure? Confusion does not always mean the tumor is coming back.”

You should contact a medical provider if you notice new or different symptoms

Patients with brain tumors who notice symptoms that are worse or represent a change from their baseline should contact their doctor. Caregivers of brain tumor patients should be aware of the patient’s normal personality and orientation and look out for changes. “Sometimes, to an observer, what looks like confusion may be a seizure or speech difficulty, which may be due to many causes. It is important to check in with your doctor to determine the most appropriate course of action,” says Chukwueke.

Learn more about symptoms of brain tumors from Dana-Farber Cancer Institute.