Craniospinal irradiation high dose as independent predictor of permanent alopecia in childhood medulloblastoma survivors: cohort study and literature review

Purpose: Our aim was to determine the main risk factors related to the occurrence of permanent alopecia in adult survivors of childhood medulloblastoma (MB) to improve their quality of life. Methods: We retrospectively analysed the clinical features of all consecutive survivors of MBtreated at our Institute. We divided the patients into 3 groups depending on the craniospinal irradiation (CSI) dose received and defined permanent alopecia first in terms of the skin region affected (whole skin and nape region) then on the basis of the toxicity degree (G). Any relationship between alopecia and other characteristics was investigated by a univariate and multivariate analysis and Odds ratio (OR) with confidence interval (CI) was reported. Results: We analysed data from 41 patients with a 10-year follow-up. High dose of CSI was found to be the independent factor leading to permanent hair loss in both groups: alopecia of the whole skin (G1 p-value 0.030, G2 p-value 0.003) and of the nape region (G1 p value 0.038, G2 p value 0.006). The posterior cranial fossa (PCF) boost volume and dose were not significant at multivariate analysis neither in permanent hair loss of the whole skin nor only in the nuchal region. Conclusion: In paediatric patients with MB, the development of permanent alopecia seems to depend only on the CSI dose exceeding 36 Gy. Acute damage to the hair follicle is dose dependent, but in terms of late side effects, constant and homogeneous daily irradiation of a large volume may have a stronger effect than a higher but focal dose of radiotherapy.