Abstract
The outcomes of intensity-modulated proton craniospinal irradiation (ipCSI) are unclear. We evaluated the clinical benefit of our newly developed ipCSI system that incorporates two gantry-mounted orthogonal online X-ray imagers with a robotic six-degrees-of-freedom patient table. Nine patients (7–19 years old) were treated with ipCSI. The prescribed dose for CSI ranged from 23.4 to 36.0 Gy (relative biological effectiveness) in 13–20 fractions. Four adolescent and young adult (AYA) patients (15 years or older) were treated with vertebral-body-sparing ipCSI (VBSipCSI). Myelosuppression following VBSipCSI was compared with that of eight AYA patients treated with photon CSI at the same institution previously. The mean homogeneity index (HI) in the nine patients was 0.056 (95% confidence interval: 0.044–0.068). The mean time from the start to the end of all beam delivery was 37 min 39 s ± 2 min 24 s (minimum to maximum: 22 min 49 s – 42 min 51 s). The nadir white blood cell, hemoglobin, and platelet levels during the 4 weeks following the end of the CSI were significantly higher in the VBSipCSI group than in the photon CSI group (P = 0.0071, 0.0453, 0.0024, respectively). The levels at 4 weeks after the end of CSI were significantly higher in the VBSipCSI group than in the photon CSI group (P = 0.0023, 0.0414, 0.0061). Image-guided ipCSI was deliverable in a reasonable time with sufficient HI. Using VBSipCSI, AYA patients experienced a lower incidence of serious acute hematological toxicity than AYA patients treated with photon CSI.
Highlights
Craniospinal irradiation (CSI) plays an essential role in the management of central nervous system malignancies such as medulloblastomas and germ cell tumors, which have the propensity to disseminate throughout the neuroaxis
There was no significant difference in the homogeneity index (HI) of the CTV between the VBSipCSI and intensity-modulated proton craniospinal irradiation (ipCSI) without VBS
The incidence of Grade 3 or more acute diarrhea was significantly reduced to 23% in psCSI from 54% in photon CSI (P = 0.023) in Song et al.’s series [16]
Summary
Craniospinal irradiation (CSI) plays an essential role in the management of central nervous system malignancies such as medulloblastomas and germ cell tumors, which have the propensity to disseminate throughout the neuroaxis. It has been documented that proton beam therapy (PBT) is superior to photon beam therapy in reducing the dose to normal tissues in CSI [1, 2]. From a biological point of view, intensity-modulated proton craniospinal irradiation (ipCSI) is expected to be superior to passive scattering (PS)-PBT for children, and adolescent and young adult (AYA) patients, because it leads to less frequent contamination of neutrons [3]. IpCSI has been shown to be superior to CSI using PSPBT (psCSI) to improve the dose distribution, especially at the junction of the fields [4, 5]. We evaluated the time required to perform ipCSI using the system for all the patients who required CSI during the study period
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
