What is 'cancer cachexia'?

(adapted from: Laure B. Bindels and Jean-Paul Thyssen, Clin. Nutr. Exp. 2016 http://dx.doi.org/10.1016/j.yclnex.2015.11.001)

Cachexia, also known as “wasting syndrome”, is a multifactorial, progressive and incurable condition that leads to the deterioration of skeletal muscle and fat stores in our body. 

Typical symptoms of cachexia include (but are not limited to) muscle and fat loss, muscle weakness and fatigue, loss of appetite, low levels of albumin, anemia, high levels of inflammatory markers and insulin resistance. Altogether, these debilitating symptoms also lead to mental fatigue and pronounced weight loss.

Although it frequently associates with cancer, cachexia can also occur in patients diagnosed with pro-inflammatory and chronic diseases such as congestive heart failure, chronic obstructive pulmonary disease (COPD), chronic kidney disease and AIDS.

Once thought to be a direct consequence of cancer-secreted factors, nowadays researchers and physicians agree on the idea that cachexia rather develops when signals released from tumor cells or as a response of the host body to the tumor crosstalk (i.e., interact) with different tissues throughout the body. The main result is the loss of body weight, muscle mass and weakness.

Up to 80 percent of patients diagnosed with advanced cancers will develop cachexia, accompanied by progressive body weight loss. This condition is estimated to cause up to 30 percent of cancer deaths, which also means that a third of cancer patients are expected to die OF cachexia rather than WITH cachexia.

Cancer cachexia is more frequently diagnosed in patients with certain types of cancer, especially pancreatic and gastric cancer, lung, esophageal, colorectal and head and neck cancer. Although several factors and disease states can promote significant loss of weight, it is important to highlight that the difference between cachexia and regular weight loss (as simply due to reduced food and calorie intake) is that it happens involuntarily, likely also because of metabolic, hormonal and inflammatory changes that cause the body to break down muscle mass uncontrollably.

We and others have shown that the development of cachexia in patients with cancer will also increase the toxicity of anti-cancer treatments and reduce their tolerability, thus also negatively impacting patients’ survival.

Although the causes of cachexia remain obscure, we now know that imbalances in the levels of several circulating factors (such as hormones, cytokines and growth factors) usually lead to weight loss and wasting of muscles, as well as to loss of bone mass, even in the absence of bone metastases.