Once diagnosed with glioblastoma, one of the most lethal and toughest forms of brain cancer, every new treatment can be life-extending. And now a new, less invasive laser technique boasts early promising results for prolonging the lives of some patients when conventional neurosurgery is considered too dangerous or not feasible. It is called laser interstitial thermal therapy, or LITT, and involves the use of a very thin laser probe to kill tissue with heat. This minimizes the size of the opening needed in the skull compared to traditional open-brain surgery.
The surgeon conducts the procedure using live MRI scans to aim the laser at the tumor and avoid healthy tissue. A significant new study, co-led by scientists at Washington University School of Medicine in St. Louis, analyzed results of 787 brain tumor patients that received the therapy as part of a prospective multicenter trial.
The results indicate that some two factors – extent of tumor cell destruction and timing of laser therapy – could be crucial in determining patient survival. This research report published in the Journal of Clinical Oncology could help physicians target laser therapy to those most likely to benefit. This has been a huge problem for clinicians and patients in the past. Typical treatment includes an operation to remove as much of the tumor as possible followed by chemotherapy and radiation.
Not all tumors are removable though. This is where LITT may be able to offer an important alternative. During the operation, surgeons drill through a tiny hole and place a laser probe that is controlled robotically.
MRI guidance will give the surgeon the ability to guide the probe until it is directly on the tumor. Heated laser will then electrocute the tumor. The precision of what was ablated also turned out important in the newer study. In patients with newly diagnosed glioblastoma, patients who had at least 91% of their tumor ablated with the laser survived approximately 2.
1 years from diagnosis (5 years for the WashU study). The researchers suggested that this data can aid in defining when the laser technique would be used earlier in patient care versus being used for recurrent or hard to reach tumors. Early this year, yet another recent study has sparked a wave of excitement for the newly introduced technology.
A multicenter randomized controlled trial (RCT) in the Netherlands was conducted on patients with unresectable glioblastoma; these patients were randomized and treated with biopsy alone versus biopsy and same-session MRI-guided laser interstitial thermal ablation (LITT), followed by standard of care, when applicable. The results were a median survival of 7.8 months in the LITT arm versus 4.8 months in the control arm; p = 0.
- Still, researchers have pointed out a crucial flaw: the trial only managed to include 26 patients in the final analysis, stopping early on so it was too small to definitively correlate the survival benefit to laser use. Further studies of greater scale will be required before firm conclusions can be drawn.
