Purpose Young patients with a brain tumour show neurocognitive alterations as both consequences of the tumour and of the treatments received. In this paper, we present the basal analysis of a prospective study of damage from radiation after focal radiation therapy (RT), correlating tumour localization, symptoms, neurological/endocrinological impairments, surgery/ies±chemotherapy, and cognitive assessments at the time of enrolment. Methods Sixty-six children eligible for focal RT underwent a neurocognitive assessment. The demographic, pathological and clinical variables with MRI morphological scans, where differenypt kind of damage scores were defined, were then analysed. Results The patients’ median age was 8 years; the most frequent tumour was ependymoma (41%), and the posterior fossa (29%) was the prevalent site. All but 2 children (with germ cell tumours), had undergone surgery and 32 sessions of chemotherapy before irradiation. Ad-hoc scores for neurological deficits and endocre alterations were created and structural abnormalities were scored in each cortical/subcortical region. Patients with posterior fossa ependymomas and infratentorial tumours showed the highest score of neurological damage while endocrine alterations were more serious in patients with craniopharyngioma and germ cell tumours of the sellar region and ventricular system. The median number of structural damaged areas was equal to 2 for each child. Neurological deficit scores were not associated with the presence of hydrocephalus and surgery/ies received, unlike endocrine deficits. Conclusion The analysis of baseline evaluations highlights damage existing prior to radiation and generated by multiple factors. In light of these findings, damage over time should be investigated by distinguishing multiple generating factors.

Introduction. Mutations of the APC (adenomatous polyposis coli) gene correlate mainly with familial adenomatous polyposis (FAP), but can occasionally be pathogenic for medulloblastoma (MBL) WNT subtype as well, the course of which has only recently been described. Methods. We retrospectively retrieved all patients with documented germline APC mutations and a centrally-reviewed diagnosis of MBL to examine the outcome of their MBL, late effects of its treatment, and further oncological events. Results. Between 2007-2016 we diagnosed and treated 6 patients, all with a pathogenic APC variant mutation, who all had MBL, classic histotype. None had metastatic disease. All patients were in complete remission a median 65 months after treatment with craniospinal irradiation at 23.4 Gy, plus a boost on the posterior fossa/tumor bed up to 54 Gy, followed by cisplatin/carboplatin, lomustine and vincristine for a maximum of 8 courses. Five of 6 diagnostic revised MRI were suggestive of the WNT molecular subgroup typical aspects. Four of 6 patients had a positive family history of FAP, while gastrointestinal symptoms prompted its identification in the other 2 cases. Four patients had developed other tumors (desmoid, MELTUMP, melanoma, pancreatoblastoma, thyroid Tir3) from 5 to 7 years after MBL. Discussion. Our data confirm a good prognosis for patients with MBL associated with FAP. Patients’ secondary tumors may or may not be related to their syndrome or treatment, but warrant adequate attention when planning shared guidelines for these patients.