X. When should radiotherapy be used in lymphoma?

Abstract

The dramatic effect of ionizing radiation on Hodgkin lymphoma (HL) tumours was reported as early as 1901, only a short time after Roentgen’s discovery of ‘X-rays’. Subsequently it became clear that lymphomas are typically radiosensitive tumours that die readily after radiation therapy (radiotherapy; RT) from a process that was initially called ‘interphase death’ that we now know as apoptosis. RT produces very high local complete response rates for all lymphoma subtypes and given this high clinical efficacy, it is not surprising that RT has played an important part in the curative treatment of a broad range of lymphomas over the past half century. Over the past decade, however, enthusiasm for using RT as part of combined-modality treatment has waned and many haemato-oncologists now view RT as outdated, unnecessary and simply replaceable with additional cycles of systemic therapy, using immunochemotherapy or other agents. This change in attitude towards RT appears unrelated to efficacy as illustrated in HL, where most experienced oncologists regard RT as the most active ‘drug’. It is perhaps instead related to understandable concerns about late side-effects that have emerged in long-term survivors from the outdated RT techniques and doses used in the past. This brief review will highlight areas of current controversy and where RT should be considered in improving outcome for patients with lymphomas.