Stereotactic guided laser-induced interstitial thermotherapy (SLITT) in gliomas with intraoperative morphologic monitoring in an open MR: clinical expierence.

Stereotactic guided laser-induced interstitial thermotherapy (SLITT) is a minimal invasive method to produce thermonecrosis in cerebral tumour tissue. Clinical data are sparse due to its limited application until now and the value of this approach for tumour control and survival time remain to be defined. Twenty-four patients (7 low-grade gliomas, 11 anaplastic gliomas, 6 glioblastomas) with brain tumours, most recurrences, were treated with SLITT, in total 30 laser procedures were performed. Under local anaesthesia a 600 micro m laser-fiber was inserted by the stereotactic-guided technique. In open low-field MR the denaturation of the tumour by a Nd-YAG-laser (1064 nm) was monitored using T 1 -weighted 3-D turbo FLASH sequences. The ablation procedure had to be stopped twice because of neurological deficit, one major infection occurred. In two cases neurological improvement was observed. Mean survival times for low grade astrocytomas, anaplastic gliomas and glioblastomas were 144 months, 39 months, 17 months, respectively. Mean survival times after SLITT were 34 months, 30 months and 9 months, respectively. Mean times to progression after SLITT for the 3 histological subgroups were 16 months, 10 months and 4 months, respectively. Five patients with low grade astrocytoma and a KI greater or equal 70 maintained a high quality functional status for 11, 20, 21, 33 and 43 months. In anaplastic tumours patients maintained a KI of 70 for a median time of 15 months and for those with glioblastoma the respective high quality duration was 7.5 months after SLITT. SLITT for selected patients with glioma could have a clinical value in a multimodality treatment schedule maintaining quality of live. Due to the minimal invasive technique, the method is a therapy of choice and may be favoured to reoperation. Major indications of this treatment are small tumours, in eloquent regions and deep seated, as well as in older patients or patients in poor functional status.