Abstract Book

S133

ESTRO 37

are required for this treatment. Since 1993, a multidisciplinary procedure has been developed in our department for the treatment of tumors in children with chemotherapy, surgery and brachytherapy. This procedure is called AMORE which consists of consecutive Ablative surgery, MOuld technique with after loading brachytherapy and immediate surgical REconstruction (AMORE) applied after brachytherapy. The purpose of the procedure is to provide therapeutic possibilities in case of recurrence, intensify local treatment and reduce late side effects such as cosmetic problems and / or loss of function. The treatment is mainly given to patients with (recurrence of) rhabdomyosarcoma at different locations such as the orbit, head-neck area or pelvis. In selected cases, patients with osteosarcoma, Ewing sarcoma, adenocarcinoma or rhabdoid sarcoma are eligible for this treatment. The procedure consists of two operations and brachytherapy during the intervening week with PDR fractions every two hours day and night. After the first operation, depending on the age of the patient, we make a CT scan under anesthesia. In this way the technicians are also able to measure the catheters without the patient being aware of the procedure being performed. The next morning the technicians make a treatment plan together with the radiotherapist. After this, the team that was involved in the operation, a radiologist and radiotherapist will discuss this plan. If everyone agrees, the physicist will do the final check and the treatment start at the end of the morning. It is an intensive treatment where good guidance of the child and parents is essential for the success of the treatment. Practicing the pulses without the parents presence in the room is essential as well. The children get used to the fact that they are from time to time, alone in the room but they are able to see and talk to their parents through videoconferencing. For nurses, doctors and brachytherapy technicians it is a matter of making the procedure as smooth as possible in order to make both the patient and parents feel at ease and well taken care of. The use of a patient-belt coupling is necessary so the young patients are able to move around during the 3 days of brachytherapy. In our experience, the freedom of movement contributes to a more successful treatment. On the other hand it is also extremely important that during all those days the catheters stay in good condition. To prevent them from kinking we load all the catheters during the intervals between fractions with check cables. The child and parents are supervised during the entire treatment by a pedagogical employee, so they have one contact person and a familiar face during the entire process. Our experience shows that it is possible to give this intensive treatment if the provided preconditions are correct. SP-0263 Every single paediatric patient needs to receive proton beam radiotherapy! G.O.R.J. Janssens 1 1 UMC Utrecht, Radiation Oncology, Utrecht, The Netherlands Abstract text Although a significant number of paediatric patients are candidate for proton therapy, criteria to prefer protons instead of photons or vice versa are lacking. As proton therapy is still not available in the majority of centers treating paediatric patients, better arguments to balance protons versus photons are needed. In order to tackle this issue a workshop with European experts in the field of paediatric (radiation) oncology was organized in Utrecht (NL), February 2018. A summary of this (consensus) workshop will be integrated in this session and should enhance radiation oncologists’ decisions.

Joint Symposium: ESTRO-PROS: Is there a reason not to deliver all curative paediatric treatments with brachytherapy or protons?

SP-0261 How can brachytherapy compete with surgery and external irradiation or are these techniques complementary? C. Chargari 1 , H. Martelli 2 , F. Guérin 2 , C. Haie-Meder 3 1 Institut Gustave Roussy, Radiation Oncology, Villejuif, France 2 CHU Kremlin Bicêtre, Pediatrics Surgery, Kremlin Bicêtre, France 3 Gustave Roussy, Radiation Oncology, Villejuif, France Abstract text Treatment modalities of children with malignancies are chosen in order to achieve high cures rates but also to minimize the risk of definitive sequelae. Radical surgical approaches have been now replaced by conservative treatments involving radiotherapy as part of a multimodal strategy. In this context, brachytherapy has been used in few specialized centers as part of the treatment of patients with rhabdomyosarcoma (RMS), based on the dosimetric advantages of this technique and in an attempt to avoid the long-term side effects of external beam radiotherapy. The management of bladder prostate RMS is an appropriate example of how do surgery and brachytherapy complete each other. In selected bladder prostate RMS, it has been shown that a multimodal strategy based on a conservative surgery combined with brachytherapy of the prostate and bladder/neck was effective for ensuring high cures rates at the expanse of acceptable morbidity rates. The surgery consists of a partial cystectomy and/or partial prostatectomy preserving the muscular layer of the trigone and the urethra. Implantation of plastic tubes is conducted peri- operatively through a transperineal approach, with four single leader plastic tubes encompassing the prostate and bladder neck. A ureteral reimplantation and testicular transposition are performed to decrease the risk of ureteral stenosis and to preserve fertility, respectively. Brachytherapy and surgery can be also clearly complementary in the management of gynecological RMS, and the choice of the optimal treatment relies on an estimate of the best therapeutic ratio, to spare fertility. In soft tissues sarcoma surgically treated, the perioperative placement of plastic tubes gives the possibility to have an accurate determination of the volume to be irradiated in case of positive surgical margin. Brachytherapy can also complete with external irradiation. Indeed, brachytherapy is a very appropriate technique for delivering a boost to the primary site when there is regional lymph node extension, or in case brachytherapy should not be given as only treatment because of tumor bulk or because of a too high risk of complication (e.g.: anal RMS). Altogether, these examples illustrate that brachytherapy should be still considered as the best irradiation modality in these selected patients, and that neither surgery nor external irradiation should be seen as competitive, but rather as complementary to give the highest probability of cure with acceptable morbidity. SP-0262 RTT specific role in brachytherapy for young children J. Wilkes 1 1 Academic Medical Center, radiotherapy Brachytherapy, Amsterdam, The Netherlands Abstract text This lecture will highlight the intensive procedure of treating (young) children with a carcinoma for several days with brachytherapy as well as which preconditions