NEW YORK (Reuters Health) - Deferral of postoperative radiotherapy in children aged 3 to 8 years with medulloblastoma is associated with worse overall survival, according to results based on the National Cancer Data Base (NCDB).
"While there may exist some children ages three and older that can be safely managed with deferred radiotherapy, further research, specifically involving molecular risk stratification, is needed to identify these subgroups," said Dr. Benjamin H. Kann from Yale University School of Medicine in New Haven, Connecticut.
"For the time being, this analysis suggests that upfront initiation of postoperative radiotherapy is associated with improved survival in these patients and should remain standard of care outside the context of a clinical trial," he told Reuters Health by email.
Because of the numerous deleterious long-term effects of postoperative radiotherapy, especially in young children, deferral of postoperative radiotherapy in favor of adjuvant chemotherapy alone is currently favored for children younger than 3 years, Dr. Kann and colleagues explain in JAMA Oncology, online August 4. There is less support for this strategy in older children.
Dr. Kann and colleagues used NCDB data to analyze recent national practice patterns of postoperative radiotherapy for pediatric medulloblastoma and their implications on patient survival.
Among 816 patients included in the study, 84.9% had postoperative radiotherapy upfront and 15.1% had postoperative radiotherapy deferred.
Postoperative radiotherapy deferral rates increased from a low of 8.1% in 2005 to a high of 27.1% in 2012, the researchers found.
Deferral rates were considerably higher for younger patients (36.8% of 3-year-olds) than for older patients (4.1% of 8-year-olds).
In the survival analysis of 474 patients, of whom 17.5% had postoperative radiotherapy deferred, five-year estimated overall survival was significantly better with upfront postoperative radiotherapy than when postoperative radiotherapy was deferred (82.0% vs. 63.4%, p<0 .001="" p="">
In multivariable survival analysis, postoperative radiotherapy deferral was independently associated with worse overall survival in all models.
"With ongoing research to further reduce the use of radiotherapy, we are concerned that families are getting overly enthusiastic professional advice to avoid radiotherapy that is not based on current evidence, but based on hypothesis in current research efforts to reduce radiotherapy usage," Dr. Kann said. "Our study helps to point out that the deferral or avoidance of radiotherapy may be detrimental, with poorer survival presumably from the tumor recurrence not obviated as yet by other treatment strategies."
At present, children ages 3 to 8 years with medulloblastoma should receive postsurgical radiotherapy to the craniospinal axis and tumor bed and chemotherapy," write Dr. Arnold C. Paulino from MD Anderson Cancer Center in Houston, Texas, and Dr. Jerry J. Jaboin from Oregon Health & Science University in Portland in a related editorial.
"However, future studies using molecular subgroups for determination of treatment may reveal that some of these patients may not require radiotherapy," they add.
SOURCE: http://bit.ly/2aNDgQA and http://bit.ly/2b7FNDi
JAMA Oncol 2016.
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