Guidelines on proton craniospinal irradiation (p-CSI) target volume selection in children are lacking. We examined the impact of target volume selection on growth of children receiving p-CSI at a institution. Records of 58 patients who received p-CSI were reviewed. Median age at treatment initiation was 8 years (range, 2 to 18 y). Spinal target volumes included whole vertebral body (WVB) in 67% and partial vertebral body (PVB) in 33%. Height z-scores before and after p-CSI were assessed using Centers for Disease Control and Prevention stature-for-age charts. Maximal Cobb angle and height z-score change were compared for WVB versus PVB p-CSI using a t test. Among 93% of patients with detailed data, median follow-up was 19 months (range, 2 to 58 mo) after radiation therapy initiation. Quantitative growth evaluations were available for 64% of patients. Median change in height z-score was −0.5 (range, −2.1 to +0.7) after treatment, representing a decrease (P<0.001) in age-adjusted height. WVB patients had significantly greater reduction in height z-score versus PVB patients (P=0.004) but no difference in Cobb angle change (P>0.05). Despite reluctance surrounding its use in younger patients, PVB p-CSI was associated with similar spinal curvature and less growth suppression as compared with WVB p-CSI; a trial comparing WVB versus PVB in children may be warranted.
*Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY
†ProCure Proton Therapy Center, Somerset, NJ
Presented (abstract) at the 59th Annual Meeting of the American Society for Radiation Oncology (ASTRO), September 24 to 27, 2017, San Diego, CA.
Supported by the National Institutes of Health/National Cancer Institute Cancer Center Support Grant (P30 CA008748). This work is also supported by a gift from Jack and Susan Rudin and the Louis and Rachel Rudin Foundation.
The authors declare no conflict of interest.
Reprints: Suzanne L. Wolden, MD, Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065 (e-mail: firstname.lastname@example.org).
Received November 20, 2017
Accepted May 17, 2018