Some Children with Hodgkin Lymphoma May Not Need Radiation Therapy
Children with Hodgkin lymphoma who have favorable clinical features and who respond early to chemotherapy may not need treatment with radiation. The finding, reported in the June 27 JAMA, is from a clinical trial of 88 patients younger than 21 with low-risk disease.
Children who had an early complete response to the chemotherapy regimen used in the trial and who were not treated with radiation (as stipulated in the study protocol) had 5-year survival rates similar to those of children who did not have the same response to chemotherapy and therefore required radiation.
"This study adds to evidence that it is possible to omit radiation even in patients treated with a less intense chemotherapy regimen and still achieve excellent long-term survival," lead investigator Dr. Monika Metzger of St. Jude Children's Research Hospital said in a statement.
Nine of 10 children with low-risk Hodgkin lymphoma survive the disease, but many will experience side effects of treatment later in life, including secondary cancers. Researchers and clinicians have been trying to identify patients for whom therapy can be refined and shortened so that they will suffer fewer long-term side effects.
—Dr. Monika Metzger
"We know we can cure Hodgkin lymphoma, but how do we cure it in a way that patients will have the healthiest lives?" Dr. Metzger said in an interview. "This study proved that it was safe to omit radiation" for certain patients.
In the nonrandomized phase II trial, 47 patients had a complete response to two cycles of combination chemotherapy known as the VAMP regimen; 41 patients did not have a complete response and therefore had radiation. The 88 patients were treated between 2000 and 2008 at St. Jude, Stanford University Medical Center, Dana-Farber Cancer Institute, Massachusetts General Hospital, and Maine Medical Center in Portland.
The patients were followed for a median of nearly 7 years. The 5-year event-free survival rates were 89.4 percent in the patients who received only chemotherapy, compared with 87.5 percent in the patients who received chemotherapy plus radiation.
These findings "highlight the continued commitment to reduce complications in the treatment of childhood malignancies," wrote Drs. Kimberly Whelan and Frederick Goldman of the University of Alabama at Birmingham in an accompanying editorial.
Five patients in the chemotherapy-only group experienced a relapse; all responded to salvage therapy with chemotherapy and radiation without the need for an autologous stem cell transplant. Four of these patients had a form of the disease called nodular lymphocyte-predominant Hodgkin lymphoma. The less intensive chemotherapy regimen may not be appropriate for children in this subgroup, the study authors noted.
Because the study population was relatively small, the authors had limited power to assess differences between study sites or to do subgroup analyses. "Thus, it would be important to confirm the results in a larger cohort," they wrote.
—Drs. Kimberly Whelan and Frederick Goldman
Dr. Metzger and her colleagues are developing a treatment regimen for low-risk patients that involves lower doses of radiation therapy and would reduce the percentage of patients who undergo radiation therapy to less than the roughly 50 percent in the current study. "Clearly, the goal is to find the best balance between chemotherapy and radiation therapy," she said.
Older patients with Hodgkin lymphoma who have similarly limited forms of the disease and who are less able to tolerate intensive chemotherapy may also be candidates for the minimal treatment approach tested in this study, Dr. Metzger noted.
"The emphasis on minimizing therapy when possible is especially important in the treatment of childhood malignancies," the editorialists wrote. They cautioned, however, that "any attempt to decrease therapy to minimize late effects must be balanced with the risk of relapse because the primary cause of death the first 10 years after diagnosis remains recurrent disease."