두경부암의 방사선치료와 림프부종

Radiation therapy (RT) is one of treatment methods of cancer using ionizing radiation (IR). Because IR damages the DNA of cells which try to divide and replicate, cells dividing and replicating faster are more susceptible to DNA damage from RT. Therefore cancer cells, which are dividing rapidly, are more likely to be destroyed by IR than normal cells. There are two different ways to deliver radiation - external beam radiation therapy (EBRT) and brachytherapy (BT). As the most common form of RT, EBRT uses an external source of IR which is pointed at a specific part of the body. Meanwhile, BT is a form of RT in which the source of radiation is a tiny radioactive seed implanted close to or within the cancer. With the evolution of new imaging technologies and RT planning, techniques of EBRT and BT also progressed. The goal of RT is to achieve local control of tumor while minimizing damage to critical organs. For patients with head and neck cancer (HN), the optimal management of HN cancer requires multidisciplinary approach. While surgery and RT are the major treatment modalities in HN cancer, a role of combined chemotherapy with RT has been spotlighted. There are a number of adverse effects of RT including mucositis, skin reaction, dysgeusia, xeostomia, osteoradionecrosis, lymphedema and hypothyroidism etc. The incidence and severity of these depends upon RT-related factors such as total radiation dose, types of fractionation, and which parts of the HN treated. Technical advancement of RT reduced the incidence and severity of acute and delayed complications related with RT, such as xerostomia or osteoradionecrosis. Likewise, it is also expected to reduce the incidence and severity of secondary lymphedema of HN, despite little evidence we have yet. Further studies are needed.