Effects of two different radiotherapies for craniopharyngiomas using stereotactic radiosurgery/ stereotactic radiotherapy or fractionated stereotactic radiotherapy

Abstract

Background: Numerous studies have reported about good tumor control with both stereotactic radiosurgery (SRS) and fractionated stereotactic radiotherapy (FSRT) for residual and recurrent craniopharyngiomas, but no studies have reported on the appropriate use of different types of radiation modalities. This study aimed to report the outcomes of SRS/stereotactic radiotherapy (SRT) or FSRT and compare tumor control in a single center. Methods: From 2014 when TrueBeamTM STx with Novalis was introduced in our hospital to 2021, 21 patients underwent SRS/SRT or FSRT with gamma knife surgery (GKS) and Novalis. We have selected the radiation modalities considering mainly the distance of the optic nerve and chiasm. Imaging and clinical follow-up data were sent and reviewed. Results: The mean age was 52 years and there were 11 men. Of the 21 total patients, three experienced SRS (GKS, 50% isodose 12–15 Gy), five underwent SRT (GKS or Novalis, 19.5–24 Gy 3 fractions), and 13 patients underwent FSRT (Novalis, 54 Gy 30 fractions). The median follow-up was 32.6 (range 17–44) months after SRS/SRT and 34.0 (range 4–61) months after FSRT. In the SRS/SRT group, the mean tumor volume decreased from 1.103 to 0.131 cm3 (P < 0.01), and in the FSRT group, from 3.015 to 1.012 cm3 (P < 0.01). No radiation-induced optic neuropathy and other acute toxicity occurred. Conclusion: Craniopharyngioma can be expected to have very good tumor control by selecting SRS/SRT or FSRT depending on the distance between the optic nerve and the tumor.

Advances and Controversies in Skull Base Tumors: Implication for Diagnosis, Treatment and Management

“…Solutions with a buttress positioned within the sphenoid sinus have been developed. Some authors proposed a fat buttress to pack the sphenoid sinus (33,57,76,77). The disadvantage of this technique is that the counterpressure is not applied in a targeted manner against the sellar floor and the fibrous scarring may complicate the surgical approach if further intervention is required.…”

The role of particle radiotherapy in the treatment of skull base tumors

“…The choice of RT dose schedule comes before the choice of radiotherapy modality/technique, as we will discuss widely in the paragraph below on selection criteria for PRT in low-grade skull base tumors. In CPs, the choice of fractionation depends first on the distance of the tumors from the optic pathways ( 76 ).…”

“…A competitive approach between different radiation technical modalities does not help in the choice of a better radiation option. In making the decision-process of each clinical case, the evaluation and choice of the most suitable fractionation radiation dose schedule based on tumor volume and spatial relationship with the organ at risk represents the first step, and the choice of the radiation modality and technique represents a secondary step ( 54 , 76 , 105 , 119 , 120 , 127 – 130 , 135 , 136 ).…”

“…Regardless of tumor histology, low-grade skull base tumors with small-medium size or at most larger volumes with a maximum diameter of 3–3.5 cm and at least 3 mm distance from the brainstem and optic pathways are typically suitable cases for radiosurgical schedules (up to a multi-session schedule with five fractions) with different technology delivery options (GammaKnife, CyberKnife, or other LINAC machines with radiosurgical equipment, proton radiosurgery) ( 76 , 105 , 115 – 117 , 119 , 120 , 128 , 129 , 135 , 136 ).…”

“…In several cases, a conventional fractionation schedule (1.8–2 Gy/fraction) is more indicated in skull base low-grade tumors considering the critical location represented by the skull base: very large or giant tumors; tumors closely involving the brainstem and/or optic pathways by abutting, compressing and enveloping these structures. In these cases, conventional fractionation has been well recognized as preferable to minimize toxicity in the brainstem, optic pathways, and other cranial nerves ( 54 , 74 , 76 , 81 , 105 , 118 – 120 , 127 – 131 , 135 – 140 ).…”