Laser interstitial thermal therapy for posterior fossa tumor

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.

Razavi et al., retrospectively reviewed a series of eight patients with posterior fossa tumors treated with LITT from an IRB approved brain tumor database (2012 to 2017) of over 200 LITT cases in our institution.

Eight patients underwent LITT targeting three metastases, two pilocytic astrocytomas, two zones of radiation necrosis after radiosurgery, and one Glioblastoma. The mean preoperative lesion volume was 4.35 cm3. The 6th-month postoperative mean lesion volume decreased from 9.64 cm3 to 5.72 cm3. Two of the tumors (GBM and a metastatic adenocarcinoma) progressed after 8.5 and 7.5 months 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 lesion remained stable or reduced at median follow-up of 14.8 months (0.4 - 37.5). Tumor related edema volume increased on the first post-operative day MRI from a mean of 9.45 cm3 to 14.10 cm3. After at least one-month post-operative follow-up, this mean decreased to 8.70 cm3. Transient partial unilateral sixth cranial nerve palsy, superficial wound infection, and a late obstructive hydrocephalus, were noted in three patients post-operatively. No mortality associated with the procedure.

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 ¹⁾.