What is the most common side effect of radiation therapy to the chest?

The most common side effect of radiation therapy to the chest is skin irritation or dermatitis. Radiation therapy targets tumors but also affects surrounding healthy tissues, particularly in areas where the skin is in close proximity to the treatment field. The skin in the breast or chest area is sensitive, and as radiation breaks down cells in this region, it can lead to symptoms such as redness, dryness, peeling, or even ulceration, collectively referred to as dermatitis.

While fatigue is also a frequent side effect experienced by many patients undergoing radiation therapy, it is not as specific to chest radiation, as individuals receiving treatment in various body areas can report fatigue. Nausea can occur, particularly if areas near the digestive tract are treated, but it's less common for radiation to the chest alone. Hair loss typically occurs in areas where radiation is directly targeted to hair follicles, which in the case of chest radiation, may not be applicable unless the treatment field includes the scalp.

Overall, the specific and localized nature of skin irritation or dermatitis makes it the most prevalent side effect among patients undergoing radiation therapy to the chest area.