Magnetic resonance image-guided laser interstitial thermal therapy for glioblastoma
Magnetic Resonance Image-Guided Laser Interstitial Thermal Therapy (MRg-LITT) is an innovative and minimally invasive medical procedure used in the treatment of certain brain tumors, including glioblastoma.
Here’s an overview of how MRg-LITT works for glioblastoma:
Patient Selection: MRg-LITT is typically considered for patients who have glioblastoma that is difficult to access with traditional surgical methods or for patients who are not candidates for open surgery due to various reasons, such as the tumor’s location within critical brain regions.
Imaging and Planning: Before the procedure, high-resolution magnetic resonance imaging (MRI) scans are used to precisely locate and map the tumor. These images are used to plan the laser treatment.
Laser Ablation: During the MRg-LITT procedure, the patient is typically awake under local anesthesia. A small incision is made in the skull, and a thin, flexible laser probe is inserted into the brain. The laser probe has an optical fiber that delivers laser energy directly to the tumor.
Real-Time MRI Guidance: The critical aspect of MRg-LITT is real-time MRI guidance. As the laser is activated, MRI scans are continuously performed to monitor the temperature changes and precisely control the heat distribution within the tumor and surrounding healthy tissue. This real-time feedback ensures that the tumor is effectively heated and destroyed while minimizing damage to healthy brain tissue.
Treatment Monitoring: The MRI images provide immediate feedback to the medical team, allowing them to adjust the laser’s power and position as needed to optimize tumor ablation.
Thermal Ablation: The laser heats and destroys the tumor cells through thermal ablation, effectively killing the cancerous tissue. The procedure is carefully monitored to ensure the entire tumor is treated.
Post-Procedure Care: After the laser ablation, the probe is removed, and the incision is closed. Patients typically stay in the hospital for a short period for observation and recovery.
MRg-LITT offers several advantages for the treatment of glioblastoma:
Minimally Invasive: It involves a smaller incision compared to traditional open surgery, leading to reduced trauma and a shorter recovery time. Precise Targeting: Real-time MRI guidance allows for highly precise targeting and monitoring of the tumor, minimizing damage to healthy brain tissue. Outpatient Potential: In some cases, MRg-LITT can be performed on an outpatient basis or with shorter hospital stays. Reduced Risk: It may be suitable for patients with tumors in challenging or critical brain areas. However, it’s important to note that MRg-LITT is not suitable for all cases of glioblastoma. Patient eligibility and the choice of treatment method depend on various factors, including tumor size, location, and the patient’s overall health. Treatment decisions are typically made in consultation with a multidisciplinary team of medical professionals, including neurosurgeons, oncologists, and radiologists. Additionally, the long-term effectiveness of MRg-LITT for glioblastoma is an area of ongoing research and clinical trials.
50 GBM patients treated with LITT, with regard to safety, efficacy, and outcomes.
Kamath et al. performed a retrospective descriptive study of patients with histologically proven GBM who underwent LITT. Data collected included demographics, tumor location and volume, tumor genetic markers, treatment volume, perioperative complications, and long-term follow-up data.
They performed 58 LITT treatments for GBM in 54 patients over 5.5 yr. Forty-one were recurrent tumors while 17 were frontline treatments. Forty GBMs were lobar in location, while 18 were in deep structures (thalamus, insula, corpus callosum). Average tumor volume was 12.5 ± 13.4 cm3. The average percentage of tumors treated with the yellow thermal damage threshold (TDT) line (dose equivalent of 43°C for 2 min) was 93.3% ± 10.6%, and with the blue TDT line (dose equivalent of 43°C for 10 min) was 88.0% ± 14.2%. There were 7 perioperative complications (12%) and 2 mortalities (3.4%). Median overall survival after LITT for the total cohort was 11.5 mo, and median progression-free survival was 6.6 mo.
LITT appears to be a safe and effective treatment for GBM in properly selected patients 1).
A study included patients with de novo or recurrent glioblastoma of the corpus callosum (n = 15). The mean patient age was 54.7 yr. The mean pretreatment Karnofsky Performance Scale score was 80.7 and there was no significant difference between subgroups. The mean tumor volume was 18.7 cm3. Hemiparesis occurred in 26.6% of patients. Complications were more frequent in patients with tumors >15 cm3 (RR 6.1, P = .009) and were associated with a 32% decrease in survival postLITT. Median progression-free survival, survival postLITT, and overall survival were 3.4, 7.2, and 18.2 mo, respectively.
LITT is a safe and effective treatment for glioblastoma of the corpus callosum and provides survival benefits comparable to subtotal surgical resection with adjuvant chemoradiation. LITT-associated complications are related to tumor volume and can be nearly eliminated by limiting the procedure to tumors of 15 cm3 or less 2).
A 51-year-old male presented after a fall with progressive dizziness, ataxia, and worsening headaches with a small, frontal ring-enhancing lesion. After clinical and radiographic progression, the patient underwent a stereotactic biopsy, confirming an IDH-WT World Health Organization Grade IV Glioblastoma, followed by LITT. The patient was subsequently started on adjuvant temozolomide, and 60 Gy fractionated – radiotherapy to the post-LITT tumor volume. After 3 months, surgical debulking was conducted due to perilesional vasogenic edema and cognitive decline, with H&E staining demonstrating perivascular lymphocytic infiltration. Postoperative serial imaging over 3 years showed no evidence of tumor recurrence. The patient is currently alive 9 years after diagnosis. Multiplex immunofluorescence imaging of pre-LITT and post-LITT biopsies showed increased CD8 and activated macrophage infiltration and programmed death ligand 1 expression. This is the first depiction of the in-situ immune response to LITT and the first human clinical presentation of increased CD8 infiltration and programmed death ligand 1 expression in post-LITT tissue. The findings point to LITT as a treatment approach with the potential for long-term delay of recurrence and improving response to immunotherapy 3)
Magnetic Resonance Image-Guided Laser Interstitial Thermal Therapy (MRg-LITT)
What is MRg-LITT primarily used for? a. Treating lung cancer b. Treating glioblastoma c. Treating breast cancer d. Treating skin disorders
Why is MRg-LITT considered for glioblastoma patients? a. It is less expensive than traditional surgery. b. It involves a larger incision than traditional surgery. c. It is suitable for all cases of glioblastoma. d. It is considered when traditional surgery is challenging or not an option.
What is the first step in the MRg-LITT procedure? a. Administering chemotherapy b. Conducting a stereotactic biopsy c. Performing a CT scan d. Using high-resolution MRI scans for tumor mapping
During the MRg-LITT procedure, what delivers laser energy directly to the tumor? a. A scalpel b. A robotic arm c. An optical fiber in a laser probe d. A radiation beam
What is the critical aspect of MRg-LITT that ensures precise treatment and minimal damage to healthy tissue? a. Real-time MRI guidance b. Post-operative care c. Chemotherapy administration d. Surgical incision size
How is the laser energy used during MRg-LITT to treat the tumor? a. It cools down the tumor. b. It freezes the tumor. c. It heats and destroys the tumor cells through thermal ablation. d. It directly removes the tumor.
What is one of the advantages of MRg-LITT for glioblastoma treatment? a. Longer hospital stays b. Increased trauma compared to traditional surgery c. Outpatient potential d. Risk reduction for all patients
What factors determine patient eligibility and the choice of treatment method for MRg-LITT? a. The patient’s hair color b. The patient’s blood type c. Tumor size, location, and overall health d. The patient’s age and gender
What is the primary focus of the case series study mentioned? a. The history of MRg-LITT b. The benefits of chemotherapy c. The safety and outcomes of MRg-LITT in GBM patients d. The development of new surgical instruments
According to the study by Kamath et al., what percentage of patients experienced perioperative complications related to MRg-LITT? a. 0% b. 3.4% c. 12% d. 26.6%
b. Treating glioblastoma d. It is considered when traditional surgery is challenging or not an option. d. Using high-resolution MRI scans for tumor mapping c. An optical fiber in a laser probe a. Real-time MRI guidance c. It heats and destroys the tumor cells through thermal ablation. c. Outpatient potential c. Tumor size, location, and overall health c. The safety and outcomes of MRg-LITT in GBM patients c. 12%