Radiation was first discovered as a treatment for breast cancer in the 1990’s.  It remains a cornerstone for curative or palliative therapy for many malignancies.  Controlling the local advancement of medically inoperable malignancies is the most common setting for radiation therapy.  The most common portion of the body where radiation therapy is applied is the chest.  Lung cancer, breast cancer, lymphoma or total body radiation in patients undergoing bone marrow transplant are the most common conditions involving the chest where radiation therapy is applied. 

            Radiation-induced lung injury (RILI) is an important dose-limiting factor when radiation is applied to the chest.  RILI is injury to the lung, which is related to the radiation dose applied to the tumor.  You should understand that in most of the above-mentioned cases the radiation used penetrates not just the tumor but the surrounding lung in the radiation field.  Newer radiation therapy techniques, which focus the radiation and spare the surrounding lung tissue, have reduced the risk of RILI.  The most common tumors to have RILI as a post- treatment complication are lung, lymphoma, and breast.

            Radiation-induced lung injury may occur in both an acute and chronic form and diagnosing it can be difficult and challenging.  The acute form has a reasonable response to treatment, which is usually a course of prednisone. The chronic form represents scarring in the lung tissue, which may result in shortness of breath and the need for oxygen therapy.  Supportive measures are the only treatment.