ESTRO 2024 - Abstract Book

S2020

Clinical - Paediatric

ESTRO 2024

Results:

The median follow-up (FU) time was 4.3 years (range, 0.8-14.7 years), since first diagnosis. Of all patients, 24.3% received PBT as adjuvant therapy within their primary treatment regimen, while 75.7% underwent PBT upon disease progression or recurrence. The estimated 3-year overall and progression-free survival rates were 98.2% (±1.7) and 94.7% (±3.0). In 18 patients (24.3%), asymptomatic, transient cyst enlargement was observed by diagnostic imaging, with no need for any intervention. The estimates for 3-months, 1- and 3-year cystic failure free survival were 82.4% (±4.4), 79.7% (±4.7) and 76.8% (±5.4), respectively ( Figure 1 ). Two nodular (after 7.8 and 17.0 months) and one cystic (after 23.5 months) progressions/recurrences occurred in-field after irradiation. At last contact, 68/70 (97.1%) children presented with an Endocrine Morbidity Score of ≥ 1 and 59/70 (84.3%) of ≥ 3. BMI-SDS value ≥ +2 was observed in 28/67 (41.8%) at last FU. Including pre-existing morbidities, vision disorders (39.2%), fatigue (32.4%), headaches (28.4%), obesity and endocrinopathies were the most commonly observed lower grade (CTCAE 1 and 2) sequelae. No ≥ grade 3 new-onset of visual impairment or deterioration, memory impairment, or cognitive deterioration occurred after PBT. The incidence of neurocognitive deficits after PBT was significantly associated with treatment factors such as the size of the PTV and the mean dose to the temporal lobes.

Conclusion:

Early results illustrate promising rates of local control with acceptable late adverse effects after surgery and modern PBT. The growth of cysts within 12 months after irradiation is generally not indicating tumor progression. Critical consideration for the size of the target volume and dose to the temporal lobes is mandatory to avoid late effects. However, longer FU is needed to confirm our findings.

Keywords: proton therapy, paediatrics, sequelae