Symptoms - Loss of Appetite and Weight Loss
Reviewed by: HU Medical Review Board | Last reviewed: January 2017. | Last updated: February 2023
Lung cancer patients often experience loss of appetite and unintentional weight loss. Loss of appetite is known medically as anorexia, and the weakness due to ill health and malnutrition associated weight loss is known as cachexia. Together, these symptoms make up cancer anorexia-cachexia syndrome (CACS) and can cause additional complications and negative effects of the health of patients with lung cancer.
Approximately half of all cancer patients experience anorexia and cachexia, and at diagnosis, approximately 60% of patients with lung cancer have already experienced substantial weight loss.1,2
Malnutrition and cachexia
Cachexia is a condition of advanced malnutrition and occurs due to the inability to ingest nutrients or the body’s inability to use those nutrients.
Cachexia can be caused by interference in the gastrointestinal tract, such as obstruction (blockage) or malabsorption (abnormal nutrient absorption),surgical treatment, or treatment-related side effects. Patients receiving chemotherapy or radiation therapy may experience nausea, vomiting, taste changes, or diarrhea, which can contribute to cachexia. The psychological distress of cancer can also affect eating.3
The loss of appetite and unintentional weight loss experienced by people with lung cancer greatly impacts quality of life. In addition, these symptoms are associated with higher incidence of post-surgical complications, less effectiveness of chemotherapy, and increased side effects from chemotherapy.
In patients with advanced lung cancer, the presence of anorexia and cachexia can also impact their ability to receive certain treatments. In more than 20% of cancer patients, cachexia is the primary cause of death.1,3
A patient’s nutritional state is generally measured by body weight. Although the range of body weight varies considerably across the human population, the range of an individual’s weight varies less, allowing doctors to note any significant weight change as abnormal. Cachexia is suspected when a patient has an unintentional weight loss of more than 5% within a six-month period, especially when the patient also has a loss of muscle mass.
A weight loss of 10% or more indicates severe deficiency which is used as an initial measurement for obese patients. A number of laboratory tests can also assist in the evaluation of a patient’s nutritional status, including the measurements of transferrin, transthyretin, creatinine, and serum albumin.3
While the best way to treat CACS is to cure the cancer, that isn’t always possible. The management of cachexia is to increase nutritional intake and stop the muscle and fat wasting by the potential use of several medications. Any causes of reduced food intake, such as gastrointestinal obstruction, nausea, vomiting, or mouth sores from chemotherapy, must be treated using appropriate palliative care interventions (pain/symptom management).3
Medications used in the palliative care treatment of cachexia include corticosteroids (prednisone, prednisolone, methylprednisone), progestational drugs (megestrol acetate and medroxyprogesterone acetate), antiserotonergic drugs (cyproheptadine, ondansetron), branched-chain amino acids (leucine, isoleucine, and valine), prokinetic agents (metoclopramide), eicosapentaenoic acid, and cannabinoids (dronabinol).3
Additional lung cancer symptoms
In addition to loss of appetite and weight loss, other symptoms of lung cancer include: