Brain Fog and Cancer

Cancer and Brain Fog

According to the Mayo Clinic, chemo brain is a common term used by cancer survivors to describe thinking and memory problems that can occur during and after cancer treatment. Chemo brain can also be called chemo fog, cancer-related cognitive impairment or cognitive dysfunction.

Though chemo brain is a widely used term, the causes of concentration and memory problems aren’t well-understood. It’s likely that there are multiple causes.
No matter the cause, chemo brain can be a frustrating and debilitating side effect of cancer and its treatment. Researchers are working to understand the memory changes that people with cancer experience.

Neurological challenges







Signs and symptoms of chemo brain may include the following:

  • Being unusually disorganized

  • Confusion

  • Difficulty concentrating

  • Difficulty finding the right word

  • Difficulty learning new skills

  • Difficulty multi-tasking

  • Feeling of mental fogginess

  • Short attention span

  • Short-term memory problems

  • Taking longer than usual to complete routine tasks

  • Trouble with verbal memory, such as remembering a conversation

  • Trouble with visual memory, such as recalling an image or list of words

There are many possible factors that might contribute to the signs and symptoms of memory problems in cancer survivors.

Cancer-related causes could include:


  • A cancer diagnosis can be quite stressful and it might lead to anxiety and depression, which can contribute to thinking and memory problems
  • Certain cancers can produce chemicals that affect memory
  • Cancers that begin in the brain or spread to the brain might cause changes in thinkin

RadiationCancer treatments

  • Bone marrow transplant
  • Chemotherapy
  • Hormone therapy
  • Immunotherapy
  • Radiation therapy
  • Surgery
  • Targeted drug therapy

Complications of cancer treatment

  • Anemia
  • Fatigue
  • Infection
  • Menopause or other hormonal changes (caused by cancer treatment)
  • Sleep problems
  • Pain due to cancer treatments

Other causes

  • Inherited susceptibility to chemo brain
  • Medications for other cancer-related signs and symptoms, such as pain medications
  • Other medical conditions, such as diabetes, thyroid problems, depression, anxiety and nutritional deficiency

Risk factors

Factors that may increase the risk of memory problems in cancer survivors include:

  • Brain cancer
  • Cancer that spreads (metastasizes) to the brain
  • Higher doses of chemotherapy or radiation
  • Radiation therapy to the brain
  • Younger age at time of cancer diagnosis and treatment
  • Increasing age