Laser Interstitial Thermal Therapy for Posterior Fossa Lesions: An Initial Experience.

BACKGROUND: The application of laser interstitial thermal therapy (LITT) for intracranial lesions in the posterior fossa tumors remains challenging due to the smaller size of this compartment as well as the thickness and angle of the occipital bone. In this study, we reviewed our experience with this treatment modality for posterior fossa lesions.

METHODS: We retrospectively reviewed our series of 8 patients with posterior fossa tumors treated with LITT from an Institutional Review Board-approved brain tumor database (2012-2017) of more than 200 cases at our institution.

RESULTS: The 8 patients underwent LITT targeting 3 metastases, 2 pilocytic astrocytomas, 2 zones of radiation necrosis after radiosurgery, and 1 glioblastoma (GBM). The mean preoperative lesion volume was 4.35 cm3 . A 6 months postsurgery, the mean lesion volume had decreased from 9.64 cm3 to 5.72 cm3 . Two of the tumors (the GBM and a metastatic adenocarcinoma) progressed after 8.5 and 7.5 months, respectively, with mortality after 1.1 and 1.6 years, respectively. Surgical resection was performed in a patient with metastatic adenocarcinoma tumor at 7.7 months after LITT. All other lesions remained stable or were diminished at a median follow-up of 14.8 months (range, 0.4-37.5 months). Magnetic resonance imaging (MRI) on the first postoperative day, showed an increase in mean tumor-related edema volume from 9.45 cm3 to 14.10 cm3 . After a postoperative follow-up of at least 1 month, this mean decreased to 8.70 cm3 . One case each of transient partial unilateral sixth cranial nerve palsy, superficial wound infection, and a late obstructive hydrocephalus were noted postoperatively. No mortality was associated with the procedure.

CONCLUSIONS: LITT is a safe and feasible treatment modality even in challenging locations like the posterior fossa. However, surgical indications should be tailored for each individual patient based on the size and location of tumor.