Why Does Cancer Cause Weight Loss?
Certain cancers can cause abnormal weight loss
Certain cancers can cause abnormal weight loss
Nearly everyone loses or gains weight at some point in their lives. Diet, exercise, pregnancy, hormonal changes and aging can all affect weight. Fluctuations are generally normal.
However, unexplained weight loss is not normal and raises questions. Could it be a sign of a serious illness, like cancer?
Weight loss can be a symptom of cancer or a side effect of treatment or the illness itself.
Losing weight for no clear reason does not mean you have cancer, however. The amount of weight lost matters. Losing a few pounds is usually not serious. But losing 10 pounds or more without explanation can be a warning sign.
“For many people with cancer, this unexplained weight loss is one of the first indications of the disease,” says Munveer Bhangoo, MD, a hematologist and oncologist at Scripps Cancer Center and Scripps Clinic. “Someone who loses this amount of weight without a clear reason should see their physician to determine what is causing it.”
What types of cancer cause weight loss?
Some types of cancer can lead to marked weight loss. This is primarily due to their impact on the body’s metabolism or the organs involved with digestion. When cancer causes severe weight loss, it is called cancer cachexia. This metabolic condition leads to muscle loss and reduced appetite.
According to the American Cancer Society, significant weight loss happens most often with cancers that affect the stomach, pancreas, esophagus and lungs. Colorectal cancer, head and neck cancer and liver cancer can also cause weight loss.
Why does cancer cause weight loss?
Several factors can contribute to weight loss in people with cancer. One key factor is the body’s increased calorie burn.
Cancer cells demand more energy than healthy cells, so the body may burn more calories at rest than normal. Cancer cells also release substances that affect how your body uses calories from food and can lead to weight loss.
Inflammation is another key factor. When the body fights cancer cells, the immune system releases substances called cytokines that increase inflammation in the body. They can disrupt normal metabolism and interfere with hormones that control appetite. This often leads to less hunger and significant weight loss.
Nausea, a common side effect of cancer, also plays a role. Patients with nausea may have little or no appetite and may be unable to keep food down.
Other factors include the location of the cancer. Cancers in the mouth or throat can make chewing or swallowing difficult.
Tumors near the abdomen, like ovarian cancer, can press on the stomach. This pressure can make patients feel full even if they eat less.
Cancer treatment and weight loss
Cancer treatments, such as chemotherapy and radiation therapy, often cause side effects that make it difficult for patients to eat and absorb nutrients.
Nausea, vomiting and loss of appetite are common side effects of these treatments. Some patients may also develop sores in their mouths, which make it painful and difficult to eat.
Cancer patients may also experience stress, depression or anxiety, which can affect their appetite and energy levels.
Role of cancer care team
If you or a loved one has cancer and is losing weight, muscle or energy, consult with your care team. They can find out what is causing these problems and give advice on how to deal with them.
Doctors look at the medical side of weight loss, including treatment side effects and overall health. They can adjust treatments to reduce negative effects. Anti-nausea medications can help relieve nausea and stimulate appetite.
Registered dietitians provide individualized nutrition recommendations to help keep weight on while accommodating for personal or cultural food preferences and side effects, such as reduced appetite, nausea, taste changes and issues chewing or swallowing.
Exercise specialists provide personalized recommendations to help prevent muscle loss and boost energy levels.
Behavioral health specialists, such as psychologists and social workers, can help patients cope with stress and other emotional challenges of cancer, which can improve energy and appetite.
Cancer support groups provide a community of shared experiences. Emotional support is crucial for cancer patients. For many, knowing they are not alone can be powerful medicine.
Cancer care at Scripps
At Scripps, cancer care focuses on the overall health and well-being of patients. A multidisciplinary team works closely to do that, including oncologists, nurses, dietitians, exercise specialists and mental health counselors.
“Medical care is just one aspect of cancer treatment,” says Dr. Bhangoo. Nurse navigators play a crucial role in guiding cancer patients through their care journey.
“At Scripps, our nurse navigators guide patients living with cancer to support services to help them feel as well as possible throughout their journey,” Dr. Bhangoo says.
Nutrition is given special attention. At Scripps, registered oncology dietitians provide personalized nutrition support for cancer patients to address their specific needs related to their type of cancer, treatment side effects and dietary preferences.