High radiotherapy dose boosts prospects for children with brain cancer

April 28, 2015
by Thomas Dworetzky, Contributing Reporter
A pair of new studies presented Sunday at the 3rd European Society for Radiotherapy and Oncology (ESTRO) Forum in Barcelona, Spain, have revealed that upping radiotherapy doses for children with an intracranial ependymoma can improve survival significantly.

Since 2004 a dose of 59.4 Gy1 has been recommended for pediatric cases worldwide, as opposed to the lower (54 Gy) dose that was in use previously, and adding a radiotherapy boost to this can improve outcome yet further in selected cases, according to Dr. Lorenza Gandola, Head of the Paediatric Radiotherapy Unit at the Fondazione IRCCS, Istituto Nazionale dei Tumori, Milan, Italy.

For children with measurable intracranial ependymoma post-surgery, she and her team, in addition to the 59.4 Gy radiotherapy dose applied to the tumor bed, also added a boost of 8 Gy, divided into two fractions to the tumor residue.

"Our strategy contributed significantly to obtaining durable local control of disease in these children, and this is more striking because they already had a poorer prognosis after surgery," Dr. Gandola said in a statement. "The hypofractionated radiotherapy boost approach represents an effective alternative to surgery in cases where further surgery cannot be performed without the possibility of causing severe and perhaps lifelong damage to the child."

Twenty-four eligible children (median age 4.5 years) out of the 143 in the Italian project received the radiotherapy boost and 15 of them are still alive without disease progression at a median of 51 months after diagnosis.

No deaths related to the treatment or major toxicity has been reported in the boost group, the researchers said. Next step for the protocol is an international clinical trial to be carried out under the auspices of the European Pediatric Oncology Society, scheduled to begin later this year.

In another report on ependymoma, Dr. Anne Ducassou, from the Institut Claudius Regaud, IUCT-Oncopole, Toulouse, France, studied the impact of the high radiation dose of 59.4 Gy, in use since 2004, on a group of 177 children treated for the condition in France between 2000 and 2013.

The researchers found that children with localized disease who had been treated with the higher radiation dose of 59.4 Gy did better than those who had received the lower dose in use until that date. Of the 177 patients included in the study, the estimated overall survival and progression-free survival (where the disease remains but does not get worse) were 90% and 67% for patients who received a dose above 54 Gy, compared with 79% and 52% who received a lower dose.

"Our work, which involved a large number of children with ependymoma, has confirmed that the treatment we carry out today is better than it was a few years ago, but there is still much work to be done. For example, we found that children younger than three, and those with more aggressive disease had a poorer outcome, and we need to look further at how we can improve their treatment, as well as identifying other children at high risk of relapse," Dr. Ducassou reported in a statement.

Professor Philip Poortmans, president of ESTRO, reflected in a statement on the pair of studies. He noted that they “demonstrate that a clear dose-effect relationship exists for tumor control and survival. While the increase from 54 to 59.4 Gy that was adopted first improves disease control and survival in a population-based study, a new study is planned to confirm the results of increasing the dose by a further 8 Gy, delivered with highly directed radiation therapy techniques that give a very localized dose to the target volume, with a low dose to the surrounding normal tissues."