[National meetings for complex cases in pediatric radiation oncology: Back on six years experience]. / Réunions nationales de cas complexes en radiothérapie pédiatrique : retour sur six années d'expérience.

INTRODUCTION: Pediatric cancers are rare, representing almost 2,500 new cases each year in France meaning 1% of all cancers. Since 2012, a twice-monthly national web-based conference was held in France. Any patient with a pediatric type cancer requiring radiotherapy can be discussed. It aims at answering the physician with specific radiation therapy questions on rare and complex indications, at promoting the use of referential and the inclusion into clinical protocols. RESULTS: From 2012 to 2018, 1,078 cases were discussed for 940 patients in 142 meetings. Mean age was 10 years old (4 months to 45 years). The mean number of attendants was 6 (2 to 32). We review in this paper the main clinical features discussed in the web-conference and the decision of the web-conference. In 85% cases, the first treatment proposed was mostly accepted, but in 15%, other proposals were done (modifications of target volumes, doses or indications). CONCLUSIONS: Between 2012 and 2018, more than 1,000 pediatric irradiation cases were discussed in our web-based conference leading to 15% of change in radiation protocol. The rarity and the complexity of these situations need those meetings. They provide a place to improve the global knowledge and the quality of the treatments provided.

Adapted strategy to tumor response in childhood nasopharyngeal carcinoma: the French experience.

PURPOSE: The aim of this study was to retrospectively study survival and long-term morbidities of children with nasopharyngeal carcinoma (NPC) treated by induction chemotherapy and concurrent chemoradiation (CRT). The total dose of radiation was adapted to the response following neoadjuvant chemotherapy. METHODS: Children with non-metastatic NPC treated in France between 1999 and 2015 were retrospectively included in the study. The strategy combined neoadjuvant platinum-based chemotherapy, followed by adapted CRT to tumor response. RESULTS: In total, 95 patients (median age 15 years [range, 7-23 years], male-to-female ratio 1.8) with undifferentiated NPC were included; 59% of patients had TNM stage IV. Intensity-modulated radiotherapy (IMRT) was delivered to 57 patients (60%), while the other patients were treated with conformal RT (3D-RT). After a median follow-up of 4.5 years [range, 3.6-5.5 years], 13 relapses and seven deaths had occurred. The 3­year overall and relapse-free survival (RFS) were 94% [95% CI, 85-97%] and 86% [77-92%], respectively. The locoregional failure rate was 6% [95% CI, 2-14]. Long-term treatment-related sequelae of grade 2+ were reported by 37 (50%) patients; odynophagia was significantly reduced treated by IMRT vs. conventional 3D-RT (7% vs. 55%, p = 0.015). Using a reduction dose of 59.4 Gy, 54 Gy, and 45 Gy, respectively, to the primary, involved, and uninvolved neck nodes, after a favorable tumor response, was not associated with an increased locoregional failure rate. CONCLUSIONS: The survival rates for NPC have been considerably improved by means of multimodal therapy, but long-term locoregional morbidity remains common. Use of IMRT may induce less residual odynophagia. Radiation dose reduction adapted to chemotherapy response does not have a negative impact on outcome. These findings support the use of an RT protocol adapted to the tumor response to neoadjuvant chemotherapy for a long-lasting improvement in the patient's quality of life.