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Cancer and its treatment can have effects that lead to changes in eating habits and the desire to eat, including a loss of appetite.
Loss of appetite is called anorexia. People with a very low appetite that lasts more than a few days usually lose weight. Losing weight from not eating enough can often make a person feel weak and have fatigue. This may affect their quality of life and ability to do usual activities. It can also affect how they respond to cancer treatments.
People with cancer might have many factors that affect their appetite, most commonly it's the cancer itself and treatment for the cancer.
Cancer itself can cause a loss of appetite for the following reasons.
Surgery and other cancer treatment-related side effects can cause loss of appetite. Some of the side effects that can affect appetite include:
It's important to remember that other non-cancer health problems and medications used to treat non-cancer problems can also cause loss of appetite.
A person who has anorexia (poor appetite or no appetite) may eat much less than normal or may not eat at all. This is common with some cancers and some treatments, but it's important to remember that everyone is different. If treatment is the main cause, loss of appetite can be temporary. If there are other factors, it can be longer lasting.
Some people who lose their appetite may have cachexia. This is a more serious problem that can lead to poor nutrition and a significant loss of weight and muscle mass.
Eating as well as you can is an important way a person with cancer can help to take care of themselves. It's important to talk to the cancer care team about any expected appetite changes before surgery for cancer, or before other types of treatment are started. Reporting appetite changes early can help limit problems from losing too much weight and having poor nutrition.
Here are some hints that may help if you are having changes in your appetite:
The American Cancer Society medical and editorial content team
Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.
Besser J, Grant BL, American Cancer Society. What to Eat During Cancer Treatment. Atlanta, GA: American Cancer Society; 2018.
National Comprehensive Cancer Network (NCCN). Clinical practice guidelines in oncology: Palliative care. Version 2.2019. Accessed at www.nccn.org/professionals/physician_gls/pdf/palliative.pdf on January 21, 2020.
Oncology Nursing Society (ONS). Anorexia. Accessed at https://www.ons.org/pep/anorexia on January 21, 2020.
Rosenzweig MQ. Anorexia/cachexia. In Camp-Sorrell D, Hawkins RA., eds. Clinical Manual for the Oncology Advanced Practice Nurse. 3rd ed. Pittsburgh, PA: Oncology Nursing Society;2014:583-590.
Ward VA. Cancer anorexia-cachexia syndrome. In Brown CG. A Guide to Oncology Symptom Management. 2nd ed. Pittsburgh, PA: Oncology Nursing Society;2015:119-136.
Last Revised: September 14, 2022
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