What is one potential side effect of radiation therapy?

Loss of appetite is a well-documented potential side effect of radiation therapy. This can occur for several reasons, including the location of the treatment and the impact radiation may have on the body's metabolism and digestive system. For example, if radiation is directed at areas like the abdomen or pelvic regions, it may disrupt normal digestive function and lead to nausea or discomfort, which in turn can reduce appetite.

Conversely, the other options do not align with known effects of radiation therapy. Increased heart rate is not typically associated with radiation treatment; such a change might be linked to anxiety or other medical conditions. Hair growth is contrary to radiation's effects, as it often leads to hair loss in the treated areas. Enhanced vision is also not an expected outcome of radiation therapy and is unrelated to the treatment's mechanics or objectives. Therefore, loss of appetite stands out as a significant and recognized side effect of radiation therapy.