Weight loss is a frequent concern for individuals undergoing radiation therapy, though the amount can differ substantially among patients. The experience is highly individualized, and this variation depends on several factors related to the treatment and a person’s overall health. Understanding why this happens and how to manage it is a part of navigating the treatment process.
Why Radiation Can Cause Weight Loss
Radiation therapy targets cancer cells, but it can also affect nearby healthy cells. This damage to normal cells causes side effects, many of which can lead to weight loss. The body also uses a significant amount of energy to heal itself during treatments, which can contribute to changes in weight.
Side effects that directly impact eating are common. Nausea, a loss of appetite, and changes in how food tastes or smells can make eating less appealing. For individuals receiving radiation to the head, neck, or chest, physical difficulties can arise, such as mouth sores, a dry mouth, or trouble swallowing, which can make eating painful.
Systemic effects like fatigue are also prevalent, making tasks like grocery shopping and meal preparation feel overwhelming. If radiation is directed at the abdomen or pelvis, it can cause gastrointestinal problems like diarrhea, which interferes with the body’s ability to absorb nutrients and calories from food.
Factors That Influence Weight Changes
The area of the body receiving treatment is one of the most significant variables. Radiation to the head and neck area is very likely to cause weight loss because it directly affects the mouth and throat, leading to pain, difficulty swallowing, and taste changes. Similarly, treatment targeting the stomach or esophagus can disrupt the digestive process.
Receiving other treatments concurrently, particularly chemotherapy, can compound the side effects that lead to weight loss. This combination often increases the severity of nausea, appetite loss, and fatigue. A person’s health before starting treatment also plays a part, as pre-treatment weight and nutritional status can influence how well the body tolerates the therapy.
The type of cancer itself can be a factor. Some cancers cause a condition known as cachexia, a complex syndrome involving weight loss and muscle wasting that is independent of treatment side effects. In these cases, the cancer contributes to the weight loss, which can be intensified by radiation.
Managing Nutrition and Weight During Treatment
Managing nutrition is a key part of mitigating weight loss during radiation therapy. The primary strategy is to consume small, frequent meals throughout the day rather than three large ones. This approach can feel less daunting for someone with a poor appetite. Focusing on foods that are high in calories and protein is also recommended.
Incorporate high-energy foods by adding butter, oils, or cheese to meals, drinking whole milk, or using nutritional supplement shakes between meals. If chewing and swallowing are difficult, soft, moist foods like scrambled eggs, soups, and smoothies are good options. A dietitian can provide personalized advice and create a meal plan for a patient’s specific needs.
Working closely with the oncology team is important for managing symptoms that interfere with eating. Doctors can prescribe medications to control nausea or diarrhea, which can make a significant difference in a person’s ability to eat comfortably.
When to Be Concerned About Weight Loss
While some weight fluctuation can be expected, it is important to know when weight loss becomes a medical concern. A guideline is the unintentional loss of more than 5% of one’s initial body weight. Losing weight rapidly, such as more than two pounds per week for several consecutive weeks, should also be reported to the healthcare team.
This level of weight loss is concerning because it can negatively affect the body’s ability to tolerate treatment and recover. Significant weight loss, particularly muscle loss, can lead to increased weakness and fatigue, impacting the ability to complete the planned course of radiation. Maintaining weight is also important because the radiation plan is designed based on a person’s specific body size; a large change could affect treatment accuracy.
Patients should monitor their weight on a weekly basis. Any significant or rapid decrease should be communicated to the oncology doctor or nurse right away, rather than waiting for the next scheduled appointment. Early intervention, such as adjusting diet or medications, can help stabilize weight and improve overall outcomes.