Long-term results of a randomised trial of involved field radiotherapy vs extended field radiotherapy in stage I and II Hodgkin lymphoma

Involved field (IF) radiation was compared with extended field (EF) radiation in Hodgkin lymphoma (HL) to ascertain whether reduced radiation fields would reduce the late sequelae of radiation without compromising disease control and survival. A total of 603 patients with stage I or II HL were entered into this trial; laparotomy was carried out in 380 (63%) patients. Stage I or IIA disease patients were randomised to receive IF or EF comprising a mantle or inverted Y fields alone. Stage I and IIB patients were randomised between mantle or inverted Y fields and total nodal irradiation (TNI). The dose was 35 Gy to uninvolved sites and 40 Gy to involved sites. The median follow-up of surviving patients was 25.2 years with only 3.3% lost to follow-up. The treatment failure rate at 25 years in stage IA and IIA was 44% after EF and 54% after IF (P = 0.01); in stage I and IIB this was 80% (EF) and 82% (TNI) at 25 years. No difference in overall survival between the randomised groups was seen. The incidence of second malignancies was 21% after IF and 20% after EF with a slight excess of lung cancer in the EF group. No significant differences in the causes of death between the randomised arms have emerged. In conclusion, IF radiotherapy for stage I and IIA HL results in a 11% greater risk of relapse compared with EF but has no effect on overall survival, risk of second malignancy or cause of death at 25 years.