BMI trajectories in the first 3 months after childhood craniopharyngioma resection: a plea for early management of BMI changes.

Objective: Hypothalamic obesity (HO) is a severe condition following childhood craniopharyngioma (cCP) treatment. Despite multidisciplinary and centralized care, severe body mass index (BMI) changes are still often encountered after cCP surgery. We aimed to perform an in-depth analysis of BMI trajectories in our cCP cohort in the first year after surgery and to identify characteristics associated with BMI change. Methods: Data were collected of cCP patients diagnosed since January 2018. Change (Δ) in BMI standard deviation scores (SDSs) from treatment to 3, 6, 9 and 12 months after and latest follow-up was assessed. Secondary outcomes were patient, tumor and treatment characteristics associated with ΔBMI SDS and interventions for postoperative weight gain. Results: Of the 35 cCP patients, the most significant BMI SDS change was observed within the first three months following cCP resection, with almost half of the patients developing an increase of ≥1.0 BMI SDS. Of patients with the most severe BMI change within the first three months, 87% were overweight or obese at 12 months after cCP resection. Pharmacological intervention for obesity started on average 10.8 months postresection. Development of arginine vasopressin deficiency was positively correlated with ΔBMI SDS in the first three months (P = 0.017). Barriers for obesity intervention in the first months following treatment are discussed. Conclusions: Following cCP resection, increase in BMI due to hypothalamic damage is most severe already in the first three months postoperatively. Postoperative rapid weight gain should be acknowledged as a consequence of hypothalamic damage and requires more early intervention aiming to prevent the development of HO.