Radiotherapy in early stage classical Hodgkin lymphoma: past, present and future

For early stage classical Hodgkin lymphoma (HL), extended field irradiation (EFRT) alone has shown excellent results in low relapse rate and high long-term survival rate. With the patients achieving long-term survival, the risk of the RT-related late complications was increased, such as secondary malignancies and heart infarctions. According to a series of studies, the combined modality therapy (CMT) as the first-line therapy has replaced the radiotherapy (RT) alone. The recommended regimens are 2 cycles of ABVD followed by involved field radiotherapy (IFRT) (20-30 Gy) for the favorable patients, and 4 cycles of ABVD followed by IFRT (30 Gy) for unfavorable patients. The involved nodular radiotherapy (INRT) has shown the potential to achieve satisfactory primary tumor control with lower RT-related toxicity than EFRT or IFRT in combined therapy. Some prospective randomized studies are going about chemotherapy (CT) plus INRT under the guidance of PET. It is not certain that whether CT alone has more benefits to cure limited HL. Appropriate application of new RT techniques can improve the radiation dose distribution in target fields and protect normal tissues from excess RT-related damage.