Radionecrosis induced by stereotactic radiosurgery of brain metastases: results of surgery and outcome of disease

Abstract

Sterotactic radiosurgery (SRS) is an effective and commonly employed therapy for metastatic brain tumors. Among complication of this treatment, symptomatic focal cerebral radionecrosis (RN) occurs in 2-10 % of cases. The large diffusion of combined therapies as SRS followed by WBRT and/or CHT, has significantly amplified the number of patients who potentially might be affected by this pathology and neurosurgeons are increasingly called to treat suspected area of RN. Results of surgery of RN in patients with brain metastases are rarely reported in literature, a standardization of diagnostic work-up to correctly identify RN is still lacking and the timing and indications in favour of surgical therapy over medical treatments are not clear as well. In this retrospective study, we review current concept related to RN and analyze the outcome of surgical treatment in a series of 15 patients previously submitted to SRS for brain metastases and affected by suspected radionecrotic lesions. After surgery, all patients except one neurologically improved. No intra-operative complications occurred. Brain edema improved in all patients allowing a reduction or even suspension of corticosteroid therapy. Pure RN was histologically determined in 7 cases; RN and tumor recurrence in the other 8. Overall median survival was 19 months. An aggressive surgical attitude may be advisable in symptomatic patients with suspected cerebral RN, to have histologic confirmation of the lesion, to obtain a long-lasting relief from the mass effect and brain edema and to improve the overall quality of life, sparing a prolonged corticosteroid therapy.

Accuracy of F-DOPA PET and perfusion-MRI for differentiating radionecrotic from progressive brain metastases after radiosurgery

“…At doses of 16-22 Gy given in a single fraction, RN may develop in up to 68 % of treated lesions, depending on several patient-related and treatment-related factors, including total delivered dose, target irradiated volume, deep location, concomitant chemotherapy etc. [6][7][8][9]. Differentiating PD from RN is of paramount importance because the treatment and management of these conditions are different.…”

“…Its efficacy, when used alone or in combination with whole-brain radiation therapy (WBRT), has been demonstrated in several randomized trials and multi-institutional studies that have shown a 12-month local control of 70 -90 % [2][3][4][5]. The most common complication of SRS is the development of brain radionecrosis (RN) that may occur in a significant proportion of irradiated lesions, especially when high single doses are delivered to large tumour volumes [6][7][8][9]. Differentiation of tumour progression (PD) from RN is challenging, as both conditions are characterized by similar neurological symptoms [10,11].…”

Irradiation and immunotherapy: From concept to the clinic

“…First, the optimal timing of SRS and ipilimumab is unknown. Furthermore, given the possibility of pseudoprogression from both radiosurgery 68,69 and ipilimumab, 70 care must be taken when determining progression on surveillance imaging after the combination of SRS and ipilimumab.…”

Radiothérapie en conditions stéréotaxiques des métastases cérébrales

“…Elle apparaît classiquement 6 à 12 mois après la radiothérapie en conditions stéréotaxiques. Après radiochirurgie, environ 50 % des lésions apparaissent comme des radionécroses pures alors que les autres sont un mélange de cellules tumorales et de nécroses [28]. L'incidence varie de 2 à 22 % pour les radionécroses radiologiques et 1 à 14 % pour les symptomatiques [29,30].…”

“…Le volume ayant reç u une dose de 12 Gy (V12 Gy) en une séance semble prédictif à 1 an (risque : 0 % si V12 < 3,4 cm 3 , > 10 % si V12 Gy > 8,5 cm 3 ) [28]. Peu de données sont disponibles pour estimer précisément le risque de radionécrose un an après radiothérapie hypofractionnée en conditions stéréotaxiques.…”