BICHE- 1: Brain Irradiation for Childhood cancer - Endocrine monitoring during the first five years is a study of endocrine monitoring after cerebral radiotherapy.

The study concerns patients in remission at the end of oncological treatment aged between 4 and 18 years at the time of inclusion and who have had radiotherapy before the age of 16, irradiating all or part of the brain, with a delay between the end of radiotherapy and inclusion of less than 5 years. Patients will be included during a routine visit to the paediatric endocrinologist.

The protocol for the Biche 1 study has been designed and discussed in a multidisciplinary and multicentre manner, based on data from the literature and the French reference document (September 2021) "National protocol for diagnosis and care - congenital pituitary deficiency".

In this population, the investigators will conduct a descriptive and exploratory study to establish recommendations for medium-term follow-up; to improve screening for endocrine deficiencies affecting the hypothalamic-pituitary axis in order to improve patients' quality of life and state of health; and to better define dose-volume constraints on the axis.

The study will also focus on better detection and characterisation of chronic fatigue as a potential sequela of pituitary deficiencies, in particular by means of a questionnaire assessing fatigue (PedsQL Multidimensional Fatigue scale) which will also be systematically administered and completed annually.The expected sample size is 100-150 patients treated for a brain tumour and 60-80 patients treated for another tumour but with an irradiation field covering all or part of the brain.

Inclusion Criteria:

• Patient aged 4 years or more (≥4) and less than 18 years (<18) at inclusion
• Treated with radiotherapy to part or all of the brain for cancer or hematological malignancy before age 16 (≤15)
• Post-radiotherapy time less than or equal to 5 years (≤5)
• In remission of this pathology at the end of oncological treatments, or, with stable residual disease without treatment for 2 years or more (≥2)
• Signature of informed consent from parents or legal guardian
• Patient affiliated to the social security system or beneficiary of such a system

Exclusion Criteria:

• Patients who have relapsed or developed a second cancer with a post-treatment delay of < 1 year
• Patient in palliative situation
• Brain irradiation with dosimetric data showing sparing of the hypothalamic-pituitary axis (Dmax hypothalamic-pituitary axis < 15 Gy)
• Patient with a known hypothalamic-pituitary axis endocrine deficit prior to radiotherapy
• Refusal of child or parents