Dosimetric Comparison of Proton Radiation Therapy, Volumetric Modulated Arc Therapy, and Three-Dimensional Conformal Radiotherapy Based on Intracranial Tumor Location

Abstract

(1) Background: Selecting patients that will benefit the most from proton radiotherapy (PRT) is of major importance. This study sought to assess dose reductions to numerous organs-at-risk (OARs) with PRT, as compared to three-dimensional conformal radiotherapy (3DCRT) and volumetric-modulated arc therapy (VMAT), as a function of tumor location. (2) Materials/Methods: Patients with intracranial neoplasms (all treated with PRT) were stratified into five location-based groups (frontal, suprasellar, temporal, parietal, posterior cranial fossa; n = 10 per group). Each patient was re-planned for 3DCRT and intensity-modulated radiotherapy (IMRT) using similar methodology, including the originally planned target and organ-at-risk (OAR) dose constraints. (3) Results: In parietal tumors, PRT showed the most pronounced dose reductions. PRT lowered doses to nearly every OAR, most notably the optical system and several contralateral structures (subventricular zone, thalamus, hippocampus). For frontal lobe cases, the greatest relative dose reductions in mean dose (Dmean) with PRT were to the infratentorial normal brain, contralateral hippocampus, brainstem, pituitary gland and contralateral optic nerve. For suprasellar lesions, PRT afforded the greatest relative Dmean reductions to the infratentorial brain, supratentorial brain, and the whole brain. Similar results could be observed in temporal and posterior cranial fossa disease. (4) Conclusions: The effectiveness and degree of PRT dose-sparing to various OARs depends on intracranial tumor location. These data will help to refine selection of patients receiving PRT, cost-effectiveness, and future clinical toxicity assessment.

The Diagnosis and Treatment of Craniopharyngioma

“…Radiation therapy implies external beam radiation therapy using photons or protons [37] (Table 1). In most cases, radiation therapy is administered at the time of progression after prior surgery.…”

Clinical Outcomes of Volumetric Modulated Arc Therapy Following Intracavitary/Interstitial Brachytherapy in Cervical Cancer: A Single Institution Retrospective Experience

“…IMRT can be used to achieve excellent treatment outcomes for CC as well as to effectively reduce side effects such as radioactive cystitis and enteritis (5). Volumetric modulated arc therapy (VMAT) is an advanced form of IMRT; VMAT results in greater conformity and shorter treatment delivery time compared with IMRT (6). At our institution, definitive VMAT has been used since 2012 for treating patients with CC.…”

Efficacy and toxicity of particle radiotherapy in WHO grade II and grade III meningiomas: a systematic review

“…28 In comparative studies of radiation dosage to "organs at risk," which include the hippocampi, cochlea, optical structures, and thalami, particle radiation therapy plans actually resulted in an overall dosing reduction in all locations as compared to plans for 3D conformal radiotherapy and intensity-modulated radiotherapy. 1,2,20 Furthermore, pediatric patients receiving conventional photon-based radiation to fields encompassing cerebral vasculature demonstrated a significant risk of vasculopathy, with nearly 20% of subjects experiencing either a transient ischemic attack or an infarction within 13 years following therapy. 50 In the present review, the high-risk meningioma studies reported that the most common toxicity was radiation necrosis but at a rate lower than the radiation necrosis rates cited for photon-treated high-grade meningiomas, which range from 6.6% to 23%.…”