Many eating problems can occur with a cancer diagnosis. Some malignancies, such as lung and pancreatic cancers, commonly result in reduced appetite, or anorexia. Other cancers, such as esophageal as well as those of the head and neck, can affect swallowing which makes it more difficult for patients to eat.
Treatment also can play a role. While anti-nausea medications have made chemotherapy treatments far more tolerable than they were 25 years ago, changes in taste and reduced appetite still can result in weight loss.
Radiation treatment to the abdomen can result in discomfort and nausea resulting in weight loss that requires management to relieve symptoms. Radiation to the head and neck area can cause a loss of appetite, too.
On the other hand, chemotherapy treatments for some cancers, particularly breast cancer, can result in weight gain, which can be a significant clinical problem.
Generally, I recommend that patients undergoing treatment continue to eat as normally as possible to avoid adding to their stress levels. There is little evidence that changing a diet when a patient has an established cancer results in a better outcome.
The National Cancer Institute’s free online book, “Eating Hints: Before, After and During Cancer Treatment,” is a good resource for coping with modifications that may have to be made because of treatment side effects.
It is important for cancer patients to try to maintain their strength and energy. Cancers, particularly advanced malignancies, can cause changes that accelerate how quickly the body metabolizes energy. This can lead to weight loss if not enough calories are consumed.
The body also requires extra calories to create healthy cells as cancer treatments, in targeting malignant cells, may also damage healthy ones. Cancer patients often burn several hundred calories a day more than similar-sized people without cancer and cancer treatment.
It is important to note that cancer patients, particularly those with advanced malignancies, often are not able to consume large increases in calories and proteins due to cancer’s effect on the body’s cellular activity.
Anorexia, associated with a loss of appetite or desire to eat, is the most common cause of malnutrition in cancer patients. Cachexia is a related condition with similar results. Changes in the body’s metabolic state, stemming from the presence of cancer, can result in increased energy consumption from the body’s proteins, particularly muscle mass. This is mediated by hormone-like proteins called cytokines and decreases appetite.
Patients with cachexia often feel ill if they try to eat more. Many of these patients are also fatigued, and find both meal preparation and eating a chore.
This is a frustrating situation for both patient and family members alike, as conventional wisdom would dictate that feeding a patient will improve energy and cancer outcomes. Patients and their families often feel guilty when they cannot overcome their low appetite and consequent weight loss.
However, clinical data suggests more and more that increased feeding in a patient with no appetite actually results in reduced quality of life, without clear evidence that it prolongs survival.
We frequently recommend that these patients avoid large meals and, instead, nibble and graze on food throughout the day. We counsel families not to hector or try to force feed patients.
Hydration and oral health are both important for cancer patients. Many cancer treatments, and some cancers themselves, tend to make patients somewhat dehydrated. This is particularly a problem in hot weather, and in patients with low energy. Maintaining hydration gives a patient a sense of well-being, as well as improved kidney function and may reduce chemotherapy side effects.
Many cancer treatments affect oral and, specifically, dental health. Patients with cancer of the head and neck receiving radiation therapy require careful attention to the teeth, as radiation and infection can result in tooth and bone loss.
In addition, with chemotherapy results and lowered white blood counts, the oral cavity is a common source of bacteria entering the bloodstream. Good oral health will reduce both side effects from chemotherapy, as well as potential infections.
We recommend introducing a new, or previously consumed, food group every week or two to see if a patient can tolerate it once treatment is completed. This should also be coupled with reductions in any liquid food supplements that the patient is taking, as the individual’s body will generally limit the number of calories taken, and the patient will begin to feel bloated.
Fruits and vegetables can be reincorporated as taste returns, and new food textures can be tolerated.
Dr. Wilson C. Mertens is vice president, medical director cancer services, Baystate Regional Cancer Program. He is one several Baystate health professionals who address issues related to cancer in this space on a rotating basis each month.