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Treatment Side Effects – Memory Problems

Some people who undergo treatment for lung cancer experience side effects of problems with their memory or concentration. Patients may describe it as fogginess or a mental fog, and it is sometimes called “chemo brain.” One potential risk factor that has been identified for putting patients at higher risk of experiencing memory problems with cancer treatment is age. Older adults seem to be more vulnerable to developing cognitive impairment from cancer treatment.1,2

Cognitive problems may start during or after treatment has finished, and they may be mild or more challenging. For some people, the changes are subtle and hardly noticeable, while others experience significant changes that affect their daily life. For most people who experience cognitive impairment with lung cancer treatment, the effects only last a short time. However, some experience long-term mental changes.1,3

Problems with cognitive function may show up as:

  • Forgetting details like names or dates
  • Trouble remembering common words
  • Loss of short-term memory
  • Difficulty concentrating
  • Inability to multitask
  • Taking longer to finish things 2,3

After treatment is finished, most people report that their symptoms of memory problems or fogginess improve. Studies have shown that about a year after treatment is completed, between 75-80% of patients say their cognitive function is back to normal.2,3

What Causes Fogginess or Memory Problems in Lung Cancer Patients?

While the side effects of fogginess or memory problems are sometimes called “chemo brain,” researchers believe that these side effects can be caused by more than just chemotherapy. Surgery, for example, which uses general anesthesia, can cause cognitive impairments. In addition, stress, depression and fatigue, which are commonly experienced by people with lung cancer, can also influence cognitive functioning. Patients who have metastases (spread of lung cancer) to the brain and who receive radiation therapy aimed at the brain may also have memory impairments. With multiple treatments that can cause these side effects, researchers commonly refer to this as “cancer treatment-associated cognitive change.”2,4

Managing Fogginess or Memory Problems

While research continues to look into the causes and possible treatments for the cognitive changes that occur in cancer treatment, there is currently no way to prevent these side effects. There are several techniques that can help manage memory problems and fogginess caused by lung cancer treatment, such as:

  • Get regular exerciseExercise helps decrease stress and improves well-being. Some studies have shown exercise can have a positive effect on cognitive functioning
  • Use tools to help – Using a daily planner or a smart phone can be helpful to keep all important information in one place, including phone numbers, medication lists and appointments
  • Get proper nutrition – Eating a diet rich in nutrients, like those from vegetables, helps support brain function
  • Using support systems – Leaning on friends and family to help with daily tasks can help patients manage memory problems
  • Focus on one thing at a time – Avoid multi-tasking, which can be difficult and frustrating when experiencing cognitive impairments
  • Talking to doctors and nurses – Patients who experience cognitive changes with treatment should discuss their side effects with their health care team 1,2,4
Written by: Emily Downward | Last reviewed: January 2017.
  1. National Cancer Institute. Accessed online on 10/30/16 at
  2. Ahles TA, Root JC, Ryan EL. Cancer- and cancer treatment-associated cognitive change: an update on the state of the science. J Clin Oncol. 2012 Oct 20;30(30):3675-86. doi: 10.1200/JCO.2012.43.0116. Epub 2012 Sep 24.
  3. Memorial Sloan Kettering Cancer Center. Accessed online on 10/30/16 at
  4. American Cancer Society. Accessed online on 10/30/16 at