By Megan Brooks
NEW YORK (Reuters Health) - Opting to forgo radiotherapy can be considered in children with Hodgkin lymphoma who achieve metabolic remission on interim positron emission tomography (PET) after doxorubicin, bleomycin, vinblastine, dacarbazine (ABVD) chemotherapy, suggest results of a small study from India.
ABVD is the standard chemotherapy protocol for treating pediatric Hodgkin lymphoma in India, Dr. Venkatraman Radhakrishnan told Reuters Health by email.
“This regimen is not commonly used in the Western world due to perceived increased toxicity. We were able to show that it is safe to omit radiotherapy in patients who achieve metabolic complete response with ABVD. This has not been reported before,” said Dr. Radhakrishnan of the Cancer Institute in Chennai.
“Avoiding radiotherapy can spare the patients the long-term toxicity like second cancers, growth failure, cardiac damage and pulmonary toxicity,” he added.
As reported in the Journal of Global Oncology online August 4, the researchers evaluated the role of PET-CT in upfront risk stratification and response-adapted treatment among patients younger than age 18 with Hodgkin lymphoma.
Forty-nine patients were stratified into three risk groups: group 1 (stage I or II with no unfavorable features, 15 patients); group 2 (stage I or II with bulky disease/B symptoms, seven patients); and group 3 (stage III/IV, 27 patients). Four cycles of ABVD-based chemotherapy were used in groups 1 and 2, and six cycles of an COPP-ABV-based regimen (cyclophosphamide, vincristine, prednisolone, procarbazine, doxorubicin, bleomycin, vinblastine) were used in group 3.
Of the 49 patients, 36 underwent upfront staging by PET-CT at diagnosis. In the remaining 13, staging was performed by contrast-enhanced CT because of resource limitations.
In the 36 patients who underwent upfront staging by PET-CT, seven (19%) were upstaged and one (3%) was downstaged by PET compared with CT.
Interim PET-CT was performed in all patients after the first two cycles of chemotherapy. According to negative interim PET responses, radiotherapy was avoided in 14 (93%) patients in group 1, two (29%) patients in group 2, and 23 (85%) patients in group 3. The three-year event-free survival for the entire cohort was 91%, and overall survival was 100%.
“Our study is retrospective in nature with small number of patients. Ideally, we need a prospective randomized trial with a large number of patients to clearly say that radiotherapy can be eliminated based on interim PET metabolic complete response,” Dr. Radhakrishnan cautioned. “There is evidence from Children’s Oncology Group trial AHOD0031 that showed that radiotherapy can be omitted in patients who achieve metabolic complete response in interim PET. The results of the European trial testing the similar hypothesis are awaited.”
He added, “Clinicians should understand that there are various chemotherapy regimens used for treating Hodgkin lymphoma. Omitting radiotherapy in patients getting ABVD cannot be extrapolated to other chemotherapy regimens. Also clinicians using ABVD should wait for results of randomized trials to decide if radiotherapy can be omitted, or they can discuss our findings with the patients’ parents and use their clinical judgment and the parents’ wish to plan the child's treatment.”
J Glob Oncol 2017.
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