Proof-of-Concept Study of the SNOEZELEN Device on Anxiety Symptoms in Patients Hospitalized for Chemotherapy in a Pediatric Oncology Department

The goal of this clinical trial is to evaluate whether the Snoezelen multisensory relaxation approach can reduce anxiety symptoms in children and adolescents aged 8 to 17 years hospitalized for chemotherapy in a pediatric oncology unit. Researchers will compare patients' symptoms during a chemotherapy cycle with Snoezelen sessions to a previous cycle without Snoezelen, in order to assess changes in psychological and physical well-being. Participants will: * Be enrolled between their first (without Snoezelen) and second (with Snoezelen) chemotherapy cycles * Complete self-report questionnaires on anxiety, depression, quality of life, and nausea * Receive 45-minute Snoezelen sessions every two days during their second hospitalization * Participate in a semi-structured interview after the final session * Provide data on medications (anxiolytics, antiemetics) and vomiting frequency during both hospitalizations