Pediatric Radiotherapy: Surgical Considerations, Sequelae, and Future Directions

Management and Surveillance of Short- and Long-Term Sequelae of Radiation Therapy for the Treatment of Pediatric Brain Tumors

“…4 The cumulative incidence of serious radionecrosis-related injury (CTCAE grade 3 or higher toxicity) occurs in 2% of patients with some suggestion that photon therapy holds a slightly higher risk compared with proton therapy. 8,10 It is difficult to distinguish radionecrosis from pseudoprogression and tumor recurrence on conventional magnetic resonance imaging (MRI) sequences as they typically present as ring-enhancing lesions. Pseudoprogression may be seen in up to 20% of patients treated with RT and appears in the initial few weeks following treatment as an enlarging ring-enhancing lesion that resolves usually in 12 weeks and is usually asymptomatic.…”

“…[34][35][36] Strokes have been documented with an incidence of 5.6% at 25 years in pediatric patients treated with photon therapy tallied at approximately four cases per 1000 patient years 37,38 and rank second in severity to excess mortality from secondary malignancies after RT. 10 Risk factors include younger age at time of treatment; volume of brain treated and location of radiation, in particular > 30 Gy to the middle cranial fossa; neurofibromatosis; obesity; insulin resistance; and poor fitness. [39][40][41] Microbleeds and cavernomas are common and can be detected on T2WI gradient echo sequences.…”

“…The cumulative incidence of secondary malignancies within the radiation portal and margins can be as high as 3 and 6% at 10 and 20 years after a tumor diagnosis, respectively, with a sevenfold increased risk relative to the general population. 4,10 Intra-axial lesions are most commonly astrocytic (20% incidence of gliomas), while extra-axial lesions mostly arise from the meninges (70% incidence of meningiomas); however, RT to the head and neck area can also cause squamous or basal cell carcinomas. [44][45][46] Secondary malignancies carry a poor prognosis with an estimated survival of less than 50% compared with a comparison cohort but the incidences are not believed to be significantly affected by multimodal treatment.…”

“…67 There have also been open trials using melatonin, donepezil, and modafinil as cognitive modulators, although the results from these trials are not yet available. 10 Needless to say, pediatric brain tumor patients receiving RT require longitudinal cognitive support and monitoring to ensure that they maintain their best quality of life as more patients continue to survive their primary tumor diagnosis.…”