Increased risk of relapse omitting radiotherapy in early PET scan negative Hodgkin lymphoma

Dr. J.M.M. Raemaekers of the Radboud university medical center Nijmegen, The Netherlands, and central coordinator of the study says, "The standard treatment for patients with clinical stage I/II Hodgkin's Lymphoma is ABVD (adriamycin, bleomycin, vinblastin and dacarbazin) chemotherapy followed by radiotherapy. Striking the right balance between initial cure through combined modality treatment and accepting a higher risk of late complications, and a higher recurrence rate after omitting radiotherapy in subsets of patients who will subsequently need intensive salvage treatment, is a matter of unsettled debate."

The main objective of the H10 trial was to evaluate whether involved-node radiotherapy could be omitted without loss of efficacy in terms of progression-free survival in patients with stage I/II Hodgkin's Lymphoma who had a negative earlyPET scan after two cycles of ABVD chemotherapy. This interim trial analysis included a total of 1137 patients with untreated clinical stage I/II Hodgkin's Lymphoma. Of these, 444 patients had favorable and 693 unfavorable prognoses. Patients in each prognostic group were randomized between standard and experimental treatment and first received two cycles of ABVD chemotherapy. Patients in the experimental arm who attained a negative earlyPET scan after the two cycles of ABVD chemotherapy were spared involved-node radiotherapy.

For patients with a favorable prognosis and a negative earlyPET scan, one progression occurred in the standard arm and nine progressions occurred in the experimental arm. For patients with unfavorable prognosis and a negative earlyPET scan, seven events occurred in the standard arm and 16 events occurred in the experimental arm. Even though there were few events and the median follow-up time short, the Independent Data Monitoring Committee concluded it was unlikely that the final results would show non-inferiority for the experimental treatment. They, therefore, advised that randomization should be stopped for earlyPET negative patients.