Late Effects of Craniospinal Irradiation Using Electron Spinal Fields for Pediatric Cancer Patients
Menée entre 1983 et 2014 auprès de 84 patients pédiatriques atteints d'un cancer (âge médian lors du traitement : 5 ans ; durée médiane de suivi : 19 ans), cette étude analyse l'efficacité et la toxicité de l'irradiation craniospinale par faisceau d'électrons lors d'une radiothérapie vertébrale
Background: For children, craniospinal irradiation (CSI) with photons is associated with significant toxicities. The use of electrons for spinal fields is hypothesized to spare anterior structures but the long-term effects remain uncertain. We studied late effects of CSI using electrons for spinal radiotherapy (RT). Methods: Records of 84 consecutive patients treated with CSI using electrons for the spine at a single institution between 1983 and 2014 were reviewed. Median age at RT was 5 (range, 1-14) years. The most common histologies were medulloblastoma/PNET (59%) and ependymoma (8%). The median prescribed dose to the entire spine was 30 (range 6-45) Gy. A subset of 48 (57%) patients aged 2-14 at RT with clinical follow up for ≥ 5 years was analyzed for late effects. Height z-scores adjusted for age before and after CSI were assessed using stature-for-age charts and compared with a t-test. Results: At median follow-up of 19 years (range, 0-38 years), the median survival was 22 years (95% confidence interval [CI], 12-28 years) following RT with 47 patients (56%) alive at last follow up. On subset analysis for late effects, 19 (40%) patients developed hypothyroidism and 5 (10%) developed secondary malignancies. Other complications reported were esophageal stricture and periaortic hemorrhage in 1 and restrictive pulmonary disease in 1 patient. Median height z-score before treatment was -0.4 (36th percentile; interquartile range [IQR], -1.0 to 0.0) and at last follow up was -2.2 (1st percentile; IQR, -3.1 to -1.6; P<0.001). Of 44 patients with spinal curvature assessments, 15 (34%) had scoliosis with median Cobb angle 15° (range, 10-35°), of whom 1 (2%) required surgery. Conclusions: Frequent musculoskeletal toxicity, predominantly decreased height, was seen with long-term follow up. Scoliosis and hypothyroidism were each seen in at least one third of long-term survivors. However, clinically-evident esophageal, pulmonary, and cardiac toxicities were infrequent.
International Journal of Radiation Oncology, Biology, Physics