The Evolving Role of Radiosurgery in the Management of Radiation-Induced Meningiomas: A Review of Current Advances and Future Directions

Abstract

Meningiomas are among the most common primary adult brain tumors, which arise either spontaneously or secondary to environmental factors such as ionizing radiation. The latter are referred to as radiation-induced meningiomas (RIMs) which, while much less common than their spontaneous counterparts, are challenging from a management point of view. Similar to spontaneous meningiomas, the optimal management of RIMs is complete surgical resection. However, given their high grade, multiplicity, tendency to invade bone and venous sinuses, and high recurrence rate, this cannot always be accomplished safely. Therefore, other therapeutic modalities, such as stereotactic radiosurgery, have emerged. In the current review, we provide an overview of the historical outcomes achieved for RIMs through radiosurgery and microsurgical resection. Furthermore, we provide a discussion of clinical and radiological parameters that affect the decision-making process with regard to the management of RIMs. We also provide an outline of recent changes in our understanding of RIMs, based on molecular and genetic markers, and how these will change our management perspective. We conclude the review by summarizing some of the current obstacles in the management of RIMs with SRS and how current and future research can address these challenges.

Brain: Radiotherapy

“…In the study of Kunert et al, 2 % of meningiomas were associated with previous radiation treatment (c) Contrast-enhanced imaging confirms the classical appearance of meningiomas; the frontal lesion was histologically confirmed (Kunert et al 2012). The average time after initial treatment was 24 years, and some of the patients developed multiple tumors which was described as a common feature by Mansouri et al (2014) and is also found in our presented case. Long-term effects after radiation include the volume loss of brain parenchyma, often correlated with cognitive decline and diffuse white matter changes (Green-Schloesser and Robbins 2012; Rane and Quaghebeur 2012;Szerlip et al 2011;Lv et al 2014), the latter often seen after whole-brain irradiation.…”

“…Although rare, the most common induced tumors are meningiomas (Fig. 4) (Kunert et al 2012;Mansouri et al 2014;Madden et al 2010). In the study of Kunert et al, 2 % of meningiomas were associated with previous radiation treatment (c) Contrast-enhanced imaging confirms the classical appearance of meningiomas; the frontal lesion was histologically confirmed (Kunert et al 2012).…”

An unusual radiological presentation of optic nerve sheath meningioma

“…Previous ionizing radiation is a known cause of ONSM 4, 5. Such secondary meningiomas tend to present at a younger age, present with multiple lesions commonly arising from the sphenoid ridge, tuberculum sellae or olfactory groove and demonstrate a higher recurrence rate 4, 6, 7.…”

“…Previous ionizing radiation is a known cause of ONSM 4, 5. Such secondary meningiomas tend to present at a younger age, present with multiple lesions commonly arising from the sphenoid ridge, tuberculum sellae or olfactory groove and demonstrate a higher recurrence rate 4, 6, 7. Histopathology also suggests that they tend to be more aggressive, with a higher tendency toward malignancy in patients who had high nose radiation therapy 4, 8.…”

“…Canalicular ONSM can often pose a diagnostic challenge for clinicians as very small lesions can compress the optic nerve and cause significant and progressive visual symptoms because the bony canal walls limit expansion. Reports have shown diagnostic delays of greater than 1 year due to this variability in radiological appearance 4 . It is strongly recommended that all cases of progressive visual loss be investigated by high-spatial-resolution MR of the orbit before and after contrast enhancement in combination with fat suppression 4, 5…”