Part II
In our last article, we discussed the problem of unintentional weight loss in the healthy asymptomatic individual. In this week’s article, we discuss the topic of weight loss in the patient with a diagnosed cancer.
Why does weight loss occur in cancer patients? As I noted last week, cancer cells utilize more energy than do normal cells so your body may need to utilize and burn more calories than it usually does at rest in order to provide enough energy for your tumor cells. Furthermore, tumor cells don’t utilize energy the same way that normal cells do—they are less efficient—so this leads to further wasting of calories via the so-called Warburg effect. The body also produces molecular substances called cytokines, which can alter the body’s metabolism to help it fight the cancer. These cytokines can increase inflammation in the body and may also decrease appetite, which reduces weight.
Certain cancers can directly affect the ingestion of food or its digestion. Cancers of the alimentary tract or of the digestive system more broadly would be expected to lead to weight loss. Ovarian cancer very commonly causes bowel obstruction, which again would interfere with caloric ingestion. In addition, ovarian cancer leads to ascites or fluid in the abdomen which presses on the stomach and so causes a feeling of fullness and so reduces food intake. Other cancers may also cause ascites, such as primary liver cancer.
There are other cancer-related problems that lead to weight loss. Emotional problems in cancer patients, such as depression or anxiety, may lead to decreased appetite and hence decreased food intake. More prominently, there are significant effects of treatment. Surgery of the GI tract may cause disruption in the normal absorption mechanisms in the gut. Radiation therapy and chemotherapy may cause nausea and vomiting with concomitant decreased appetite and reduced caloric intake. Diarrhea also causes weight loss as well as dehydration, so both calories and fluid loss may need to be replaced.
It is certainly the case that patients, as their disease progresses, almost always lose weight. This needs to be carefully monitored. Severe weight loss can make it more difficult to cope with the disease as well as with the side effects of the various treatments. Because of the changes in metabolism precipitated by the cancer, significant weight loss can transpire even in the setting of normal eating. In the very late stages of cancer, this may progress to a condition known as cachexia. In this condition, there is severe weight loss as we have been discussing, but in addition there is also loss of muscle and fat mass from the patient’s body; the precise physiologic and pathologic mechanisms that underlie cachexia still remain unexplained.
So what can one do to alter this grim pathway? Personally, I am not a big fan of drugs for weight management and very rarely use them. For most patients, judicious use of high-calorie foods in their diets will usually suffice. When you are able to eat, make it count. Eat protein smoothies, or utilize Ensure. Take frequent high-energy snacks like nuts, peanut butter, hard boiled eggs and cheese. Eat your favorite foods—have an omelet or oatmeal even for supper if that is what you like. Put butter or cream cheese on your bread or bagels. And olives are high-calorie—put them on your salad. (Why are you eating a salad anyway?) Now is the time for a milkshake or malted.
The best treatment for weight loss is successful treatment of the underlying tumor. But numerous drugs have been attempted to improve weight loss in this setting. Perhaps the most successful have been megestrol acetate (Megace) and corticosteroids. It is no surprise that steroids work—they produce a sense of euphoria and thereby enhance the appetite. However, the beneficial effects are not long-lasting. A randomized trial that compared steroids to Megace showed that the Megace was superior.
Megace has always been my personal favorite go-to for the pharmacologic management of weight loss. It is a progesterone analogue that is used in the treatment of metastatic breast cancer and was found to cause weight gain as one of its adverse effects—but this turned out to be a boon for those with weight loss from advanced cancer. The downside is that the extra body mass from Megace is from fat tissue and not from lean body mass. Nonetheless this does seem overall to benefit patients and it has a minimal side effect profile.
Finally, another drug that has proved efficacious is dronabinol (Marinol), a cannabis derivative. I think cannabis is going to prove effective for everything. But it does seem effective at least for improving appetite, though not as effective as Megace.
Alfred I. Neugut, MD, PhD, is a medical oncologist and cancer epidemiologist at Columbia University Irving Medical Center/New York Presbyterian and Mailman School of Public Health in New York. Email: [email protected].
This article is for educational purposes only and is not intended to be a substitute for professional medical advice, diagnosis, or treatment, and does not constitute medical or other professional advice. Always seek the advice of your qualified health provider with any questions you may have regarding a medical condition or treatment.
