Early Relapse Risk Higher When Omitting Radiotherapy in PET-negative Early Hodgkin Lymphoma
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The risk of early relapse is increased when radiotherapy is omitted in patients with stage I/II Hodgkin lymphoma whose PET scan findings are negative, according to an interim trial analysis. Both arms of this trial found that early outcomes were excellent; however, the trial's final analysis should reveal whether these initial findings are maintained over time.
“The standard treatment for patients with clinical stage I/II Hodgkin Lymphoma is ABVD (adriamycin, bleomycin, vinblastine, and dacarbazin) chemotherapy followed by radiotherapy,” said the study's central coordinator, John M.M. Raemaekers, MD, PhD, of the Radboud University Medical Center in Nijmegen, The Netherlands. “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 this 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 lymphoma who had a negative early PET scan after two cycles of ABVD chemotherapy.
This interim trial analysis included a total of 1,137 patients with untreated clinical stage I/II Hodgkin lymphoma. Of these, prognoses were favorable for 444 patients and unfavorable for the remaining 693 patients.
Patients in each prognostic group were randomized to receive either standard or experimental treatment. They all first received two cycles of ABVD chemotherapy. Patients in the experimental arm whose early PET scan was negative after the two cycles of ABVD chemotherapy did not receive the involved-node radiotherapy.
Among the patients with a favorable prognosis and a negative early PET scan, one disease progression occurred in the standard arm and nine progressions occurred in the experimental arm. For patients with unfavorable prognosis and a negative early PET scan, seven progressions occurred in the standard arm and 16 progressions occurred in the experimental arm.
Even though there were few progression events and the median follow-up time was short, the Independent Data Monitoring Committee concluded that the final results were not likely to show noninferiority for the experimental treatment. They, therefore, advised that randomization should be stopped for early PET-negative patients.
The study was closed for recruitment in June 2011 with a total of 1,952 patients. This interim analysis was published in the Journal of Clinical Oncology (2014; doi:10.1200/JCO.2013.51.9298).