The involved field is back: issues in delineating the radiation field in Hodgkin's disease

During the last century, the role of radiation therapy in the treatment of Hodgkin's disease (HD) has changed drastically. From a palliative treatment reserved for bulky lymph nodes of an incurable disease at the beginning of the century, to an exciting primary treatment used alone to cure most stages in the 1960s and 1970s, to the present more limited role as consolidation treatment after chemotherapy. Interestingly, the radiation field size has always influenced the evolution of treatment principles of HD. Over several decades, large or extended field radiotherapy has become synonymous with the successful treatment of HD. But the critical transformation from a single-modality to a combined-modality therapy, together with improvement in imaging and radiation planning techniques, mandates a reassessment of the delineation of appropriate radiation fields in HD. In this manuscript we review the comeback of the involved field, address design questions and offer field borders for common disease sites.