ASTRO: The International Lymphoma Radiation Oncology Group (ILROG) has
issued a guideline that outlines the use of 3-D computed tomography
(CT)-based radiation therapy planning and volumetric image guidance to
more effectively treat pediatric Hodgkin lymphoma and to reduce the
radiation dose to normal tissue, thus decreasing the risk of late side
effects. The guideline will be published in the March-April issue of Practical Radiation Oncology (PRO), the clinical practice journal of the American Society for Radiation Oncology (ASTRO).
Historically, pediatric Hodgkin
lymphoma patients were treated with the same chemotherapy and radiation
regimens as adults with Hodgkin lymphoma, which potentially exposes
their young, still-growing bodies to more treatment than necessary.
Previous radiation therapy guidelines for pediatric Hodgkin lymphoma
have focused on 2-D imaging and bony landmarks to define dose volumes
for radiation therapy treatment, and treated large volumes of normal
tissue in part because of uncertainty about which lymph node areas were
involved.
The guideline, “Implementation of contemporary radiation therapy
planning concepts for pediatric Hodgkin Lymphoma: Guidelines from the
International Lymphoma Radiation Oncology Group,” describes how to
effectively use modern imaging and innovations and advances in radiation
therapy planning technology to treat patients with pediatric Hodgkin
lymphoma while decreasing the risk of late side effects, including
second cancers and heart disease.
The authors describe methods for identifying target volumes for
radiation therapy, and how to implement the concept of “involved site
radiation therapy” to define radiation target volumes and limit dose to
normal organs at risk. According to the guideline, accurate assessment
of the extent and location of disease requires both contrast-enhanced CT
as well as fluorodeoxyglucose-PET (FDG-PET). The document describes how
the evaluation of response to chemotherapy influences the targeting of
the lymphoma and the volume of normal tissue treated, by using recently
developed capacity to fuse CT and FDG-PET images taken before and after
chemotherapy to CT imaging taken for radiation therapy planning.
“The emergence of new imaging technologies, more accurate ways of
delivering radiation therapy and more detailed patient selection
criteria have made a significant change in our ability to customize
treatment for many cancer patients,” said David C. Hodgson, MD,
associate professor in the Department of Radiation Oncology at the
University of Toronto in Toronto, a radiation oncologist at Princess
Margaret Hospital/University Health Network in Toronto and lead author
of the guideline. “This guideline has the potential to reduce the
radiation therapy breast dose by about 80 percent and the heart dose by
about 65 percent for an adolescent girl with Hodgkin lymphoma. This
shift in more personalized treatment planning tailored to the individual
patient’s disease will optimize risk-benefit considerations for our
patients, and reduce the likelihood that they will suffer late effects
from radiation therapy. We are also excited that these guidelines will
be utilized in an upcoming Children’s Oncology Group Study of
involved-site radiation therapy for high-risk Hodgkin lymphoma patients
and eagerly await the study’s results.”
For a copy of the study manuscript, contact ASTRO’s Press Office. Learn more about PRO.