Laser interstitial thermotherapy (LITT) for the treatment of tumors of the brain and spine: a brief review

Introduction

Laser Interstitial Thermotherapy (LITT; also known as Stereotactic Laser Ablation or SLA), is a minimally invasive treatment modality that has recently gained prominence in the treatment of malignant primary and metastatic brain tumors and radiation necrosis and studies for treatment of spinal metastasis has recently been reported.

Methods

Here we provide a brief literature review of the various contemporary uses for LITT and their reported outcomes.

Results

Historically, the primary indication for LITT has been for the treatment of recurrent glioblastoma (GBM). However, indications have continued to expand and now include gliomas of different grades, brain metastasis (BM), radiation necrosis (RN), other types of brain tumors as well as spine metastasis. LITT is emerging as a safe, reliable, minimally invasive clinical approach, particularly for deep seated, focal malignant brain tumors and radiation necrosis. The role of LITT for treatment of other types of tumors of the brain and for spine tumors appears to be evolving at a small number of centers. While the technology appears to be safe and increasingly utilized, there have been few prospective clinical trials and most published studies combine different pathologies in the same report.

Conclusion

Well-designed prospective trials will be required to firmly establish the role of LITT in the treatment of lesions of the brain and spine.

Laser Interstitial Thermotherapy for Treatment of Symptomatic Peritumoral Edema After Radiosurgery for Meningioma

BACKGROUND

Symptomatic peritumoral edema (PTE) is a known complication after radiosurgical treatment of meningiomas. Although the edema in most patients can be successfully managed conservatively with corticosteroid therapy or bevacizumab, some medically refractory cases may require surgical resection of the underlying lesion when feasible. Laser interstitial thermotherapy (LITT) continues to gain traction as an effective therapeutic modality for the treatment of radiation necrosis where its biggest impact is through the control of peritumoral edema.

CASE DESCRIPTION

A 56-year-old woman with neurofibromatosis 2 presented with a symptomatic, regrowing left frontotemporal lesion that had previously been radiated, then resected with confirmed recurrence of grade I meningioma, and subsequently radiated again for lesion recurrence. Given her history of 2 prior same-side craniotomies, including a complication of wound infection, she was not a candidate for further open surgical resection. Having failed conservative management, she underwent LITT with intraoperative biopsy demonstrating viable grade I meningioma. Postoperatively, she demonstrated radiographic marked, serial reduction of PTE and experienced resolution of her symptoms.

CONCLUSIONS

This case demonstrates that LITT may be a viable alternative treatment for patients with meningioma with symptomatic PTE who have failed medical therapy and require surgical intervention.

Histologic findings associated with laser interstitial thermotherapy for glioblastoma multiforme

Background

Laser-interstitial thermal therapy (LITT) has been supported by some authors as an ablative treatment of glioblastoma multiforme (GBM). Although the effects of LITT have been modeled in vivo, the histologic effects in a clinical circumstance have not been described. We analyzed tissue from a patient who underwent LITT as primary treatment for GBM.

Case presentation

A 62-year-old male was diagnosed with a left temporal GBM and underwent LITT at an outside institution. Despite corticosteroid therapy, the patient was referred with increasing headache and acalculia associated with progressive peritumoral edema two weeks after LITT procedure. En bloc resection of the enhancing lesion and adjacent temporal lobe was performed with steroid-independent symptom resolution (follow-up, > 2 years). Histologic analysis revealed three distinct histologic zones concentrically radiating from the center of the treatment site. An acellular central region of necrosis (Zone 1) was surrounded by a rim of granulation tissue with macrophages (CD68) (Zone 2; mean thickness, 1.3 ± 0.3 mm [±S.D.]). Viable tumor cells (identified by Ki-67, p53 and Olig2 immunohistochemistry) were found (Zone 3) immediately adjacent to granulation tissue. The histologic volume of thermal tissue ablation/granulation was consistent with preoperative (pre-resection) magnetic resonance (MR)-imaging.

Conclusion

These findings are the first in vivo in humans to reveal that LITT causes a defined pattern of tissue necrosis, concentric destruction of tumor and tissue with viable tumor cells just beyond the zones of central necrosis and granulation. Furthermore, MR-imaging appears to be an accurate surrogate of tissue/tumor ablation in the early period (2 weeks) post-LITT treatment. Surgery is an effective strategy for patients with post-LITT swelling which does not respond to steroids.