**Abstract**

Radiotherapy (RT) is a cancer treatment that has been widely applied to cancer patients. However, this treatment could induce radiation skin injuries that affect the quality of life of patients. The radiation-induced ulcer is a late-stage complication of radiation burns that could not be self-limited. This chapter summarizes current knowledge relating to RT-induced skin reactions, including epidemiology, pathophysiology, diagnosis, prevention, and management. Additionally, the author also presents the experience of treating RT-induced ulcers by surgical treatments that were shown to give satisfactory results on patients.

**Keywords:** flap, radiotherapy, radiation treatment, radiation-induced ulcer, single-stage reconstructive surgery

### **1. Introduction**

Radiotherapy (RT) is a measure that delivers radiation to cancer cells that consequently killed these cells. Radiation could be delivered in the form of ionizing particles, photons, or electron beams [1]. Recently, hyperthermia (HT) has been deemed to be a potent radiosensitizer that could enhance the efficacy of radiotherapy in cancer patients [2, 3]. RT-induced skin injuries, or radiation burns, were classified into 4 grades according to Radiation Therapy Oncology Group (RTOG) where the ulceration is included in grade 4 [4].

Although RT brings therapeutic potents to cancer patients, its side effects have been reported in many studies including RT-induced ulcers, which are the most severe situations of radiation burns [4, 5]. The presence of HT, which is often in the combination with RT, in some cases also could increase thermal toxicity [6]. These complications significantly impact patients' quality of life. Thus, a comprehensive understanding of RT-induced ulcers is critical for clinical practices.

This chapter aims to summarize relevant aspects of RT-induced ulcers, including pathophysiology, diagnosis, risks factor of RT-induced skin reactions, epidemiology, prevention, and management of RT-induced skin injuries. The chapter also focuses on the surgical management of RT-induced ulcer, a severe complication of radiation burn.
