Laser interstitial thermal therapy with and without MRI guidance for treatment of brain neoplasms – A systematic review of the literature

Abstract Background and objectives: The use of laser interstitial thermal therapy (LITT) under magnetic resonance imaging (MRI) guidance has been reported on in the literature in close to 16,000 patients with various forms of malignant and benign neoplasms. This includes studies with over 7600 patients with malignant head and neck cancer; over 250 with malignant (and refractory to other therapies) head and neck cancer; over 6600 with liver cancer; and over 1100 with benign neoplasms. As well, LITT under MRI guidance has been studied in malignant (and refractory to other therapies) lung and breast cancers with close to 300 cases reported on in the literature. To date, the sum total experience of LITT with or without MRI guidance in treating brain neoplasms has not been reported on. It is the intention of this review to do so. Methods: A systematic review of the literature was undertaken to identify all studies where one or more patients were treated with LITT with or without MRI guidance (LITT±MRI) for brain neoplasms. The following sources were searched (from 1990 to present): PubMed, Cochrane Review of RCTs, Technology Assessment websites (NICE, CTAF, CADTH, BCBS TEC), clinical guidelines for treating malignant brain neoplasms (NCCN, AANS), relevant clinical journals where the use of LITT would be reported on; and the websites of companies involved in the manufacture and market of these types of products. Results: Twenty-three articles (22 peer-reviewed and one abstract) were identified. After duplicate studies (n=6) were removed, 17 studies with 169 patients were identified who received LITT±MRI (mean age, 54±13.3 years; ratio male/female, 66%/34%). Most patients were reported on in the literature as case series. One study however, examined use of LITT + brachytherapy in a randomized fashion. These 169 patients were further broken out by type of tumor(s) and outcomes evaluated. Ninety-nine patients were treated for glioblastoma, recurrent malignant gliomas and, recurrent glioblastomas using LITT as a follow-on/salvage therapy (average age, 58.9 years). LITT used as the sole or as adjunctive therapy appeared to prolong survival (when evaluated against historical cohorts of patients with similar baseline characteristics) versus best/palliative care in this group. This was especially true where LITT was used in brain malignancies refractory to other therapies. Twenty-four patients (average age, 40.9 years) were treated for astrocytomas (WHO I–III) and LITT was used mainly with de novo lesions in areas of inoperability/eloquence. In these tumor types, LITT appeared to be well tolerated and significantly reduced lesion size. Twenty-three patients were treated for metastatic disease (average age, 60.1 years). Equivocal benefit was found in this small cohort. All lesions treated, no matter the tumor type, in these 169 patients were ≤5 cm in diameter. Most patients underwent LITT treatment with Karnofsky index (KI) of ≥60 (where reported). Most patients experienced either a stable or increased KI after LITT (where reported). Perioperative complications (e.g., neurological changes) were mainly transient in nature. Conclusions: The largest cohort of patients with recurrent glioblastoma/malignant glioma demonstrated longer survival times with stable to improved KI after LITT. These results compare favorably to second craniotomy procedures for malignant gliomas. Secondly, LITT appears to provide reasonable outcomes in patients where a second craniotomy may not be indicated (deep/inaccessible tumors or tumors in/near areas of eloquence). More published studies are required, most especially in patients with metastatic disease and in less aggressive type cancers based on the small numbers of patients studied in these groups.