For a patient receiving radiation treatment for breast cancer, which of the following would be a common side effect?

Patients receiving radiation treatment for breast cancer commonly experience skin irritation and fatigue as side effects. Radiation therapy targets cancerous cells, but it can also affect surrounding healthy tissues. This often leads to skin changes in the area being treated, which may appear as redness, blistering, or peeling. These skin irritations are a direct result of the radiation's effect on rapidly dividing skin cells.

Additionally, fatigue is a prevalent side effect of radiation therapy. While the treatment aims to eliminate cancer cells, the body expends significant energy to recover from the effects of the radiation and to heal, leading to a feeling of overall tiredness and decreased energy levels. This fatigue can persist during and after the treatment.

Other options presented do not typically correlate with the effects of radiation therapy. Weight gain and increased appetite are generally not seen as direct side effects of this treatment, and enhanced mobility is not a common outcome; instead, patients may experience temporary limitations due to fatigue or discomfort from skin irritation. Thus, skin irritation and fatigue are the most recognized side effects faced by patients receiving radiation treatment for breast cancer.