The National Cancer Institute says that anorexia is a lack of appetite; cancer cachexia is considered a wasting syndrome characterized by loss of muscle and fat directly caused by tumor involvement. Cancer cachexia is almost universally accompanied by anorexia, and in fact the same factors tend to cause both anorexia and cachexia.
Cancer cachexia and cancer anorexia are similar syndromes that occur in patients with advanced-stage, metastatic and refractory disease. Together they are regarded as the anorexia/cachexia syndrome. Signs and symptoms of this include:
- Loss of lean tissue
- A decline in performance status (what the patient is physically capable of doing)
- Fluctuations in resting energy expenditure
- Loss of appetite
Losing both fat and lean tissue is common in this syndrome, but it is the loss of lean tissue—specifically skeletal muscle—which is considered the more profoundly impacting of the two.
Contrary to intuition, the use of feeding tubes or other methods of getting nutrients into patients with this syndrome are entirely ineffective and most treatment guidelines discourage their use. The same is true for such things as dietary counseling.
Since attempts at aggressive feeding methods typically fail, researchers have concluded that the syndrome isn't about the patient's lack of sufficient nutrition; rather, it is a result of the cancer
As one might imagine, the anorexia/cachexia syndrome is a very difficult one for the patient's family and friends to cope with psychologically; as the patient weakens, they become more and more dependent on caregivers, while traditions such as family meals disappear. Additionally, it is distressing to watch helplessly as a loved one wastes away.
If all of this weren't difficult enough, anorexia/cachexia is also associated with a smaller set of overall treatment options for the patient. Notably, increased weight loss makes chemotherapy treatments that much more toxic, and studies show that as the syndrome develops, tumors become more resistant to therapy.
This syndrome is typically seen in patients at the time of their diagnosis if they are diagnosed with subtypes that include non-small cell lung cancer, upper gastrointestinal cancers, and pancreatic cancer. Early onset of the syndrome is very uncommon in subtypes such as colorectal cancer, breast cancer, and many of the lymphomas, although these patients may experience the syndrome during their final weeks or so of life.
The prognosis for patients who develop this syndrome is extremely poor. The loss of more than five percent of pre-disease weight before receiving chemotherapy itself predicts shorter survival times, a factor that is independent of performance status, disease stage or tumor type (histology). Since chemotherapy is increasingly ineffective in these patients, this makes prognosis even worse. Ultimately, weight loss and loss of appetite (anorexia) are strong indicators of poor prognosis. In fact, even after adjusting for other prognostic factors, patients who experience anorexia have a much worse prognosis in general than those patients who maintain an appetite.
Source: NCI, Education in Palliative and End-of-Life Care for Oncology
