Why Does Cancer Cause Weight Loss?

Kathryn E. Vinson, MS, CCRC

One of the aspects of cancer that seems to affect most warriors, regardless of cancer type or treatment, is weight loss.  What is the connection between weight loss and cancer?  There are actually multiple reasons for this, some coming before a diagnosis, others as a result of treatments.

Weight Loss as a Symptom of Cancer

Many types cancers may announce their presence in our systems with the symptom of weight loss.  This symptom is common in pancreatic, esophageal, stomach, and lung cancers.  Any unexplained weight loss of ten pounds of more should be reported to your doctor for further evaluation.

Doctors have coined the term cancer cachexia, or sometimes cancer anorexia cachexia, to describe the condition.  Put into simple terms cachexia is a complex conditions affecting the metabolism.  It is associated with underling illnesses, and shows itself through the loss of muscle mass and sometimes the loss of body fat. This condition is diagnosed when other conditions that can affect weight loss are absent including, but not limited to, depression, diabetes, and thyroid disease.  Cachexia is a complex mechanism that causes weight loss in cancer patients.  The condition causes decreased appetite, which in turn has your body looking at itself for nutrition.  In this we see loss of fat stores and loss of muscle mass, along with increasing fatigue.  This becomes a terrible, vicious cycle.  In pancreatic cancer, the tumors can even release chemicals known as cytokines that rev up the metabolism, causing the patient to burn more calories that he/she is taking in.  As you would expect, the greater the weight loss and decrease in muscle mass, the poorer the patient’s projected outcome.

Treatment for cachexia is as complex as the condition itself.  Doctors must work to rebalance the underlying metabolic issues occurring.  After these have been addressed, patients can focus more on caloric intake.  Experts stress the fact that this condition is distinct from starvation, as patients may be eating and taking in adequate calories, but are not maintaining/gaining weight. Doctors also encourage patients to look at meal time from a social standpoint rather than just nutritional – think of the wonderful family time that can be had sitting around the dinner table.  Multiple small, calorie dense meals throughout the day are also helpful to patients.  Meal replacement beverages such as Ensure® can give a boost between meals.

It is of vital importance to identify cachexia in its earliest stages for many reasons – one of those being maintaining strength for treatment.

Treatment Induced Cancer Weight Loss

So, what about when the treatments that are supposed to save our lives make us sick too? Both radiation and chemotherapy are well known in their ability to produce nausea and vomiting.  It is difficult to impossible to know who will be affected by these symptoms, as two people receiving similar treatments can and will react very differently. The reasons for these differences are sometimes easy to spot, but other times can be puzzling.  While chemotherapy and radiation in and of themselves can produce nausea, chemotherapy can also take a more circuitous route.  In “Recognizing the Early Signs of Anemia”, we talked about how chemotherapy targets rapidly dividing cells.  The cells that line our digestive tract – from our mouth all the way, are such rapidly dividing cells.  When this lining is damaged, a multitude of symptoms can result – difficulty chewing and swallowing, nausea, indigestion, vomiting, and malabsorption, just to name a few.  Every one of these can result in cancer weight loss. In an effort to combat these symptoms, doctors recommend eating smaller, but more frequent meals in an effort to go easy on your digestive system.

Regardless of the cause, weight loss before and during cancer treatments can have devastating effects from both physical and emotional perspectives. From changing the way we see and feel about our bodies, to decreased efficacy of treatments, cancer weight loss is a serious condition.  Here at Cancer Horizons we urge you to have open and honest discussions with your doctor if you are experiencing or fear that you may experience weight loss due to cancer.  Don’t be silent and think – this is just going to happen – be proactive in your battle.

As always, much love, abundant blessings, and many prayers to all of the cancer warriors and their families.

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