[Photodynamic diagnosis and fluorescence-guided resection of malignant gliomas: a report of 15 cases].

Objective: To study the usefulness of the intraoperative photodynamic diagnosis (PDD) and fluorescence-guided resection of malignant gliomas.

Methods: Fifteen consecutive patients with malignant gliomas received doses of hematoporphyrin derivative (HPD, 2 mg/kg body weight) 48 hours before induction of anesthesia. After the tumors recognized by bare eyes they were removed routinely. The fluorescence around 690 nm excited by laser beam (wavelength 632.5 nm) was detected by laser electronic spectrum analyzer and then fluorescing tissue was removed whenever it was considered safel. Tissue samples derived from the walls of tumor cavities after resection and PDD were sent for histological examination. Compared with the result of the histological examination, the sensitivity and specificity of PDD were calculated and recorded. Early postoperative MRI or CT were done to determine the extend of the resection of the tumors. Surgical mortality and morbidity were also recorded.

Results: Intraoperatively, in all of 15 cases tumor areas with HPD fluorescence could be recognized by laser electronic spectrum analyzer. On the basis of 106 tissue samples derived from 15 tumors, a sensitivity of 90.6%, a specificity of 96.8% and an accuracy of 94.3% of PDD were achieved. In 2 cases the resection of residual tumor were performed after finding left tumors by PDD. Complete resection of contrast-enhancing tumor was accomplished in 9 patients (60%). Residual intraoperative tissue fluorescence left unresected for safety reasons predicted residual enhancement on MR images in 5 of the 6 remaining patients. No perioperative deaths and one case of morbidity were encountered.

Conclusions: Intraoperative photodynamic diagnosis following resection of malignant gliomas can detect residual tumor tissue with high accuracy. Photodynamic diagnosis and fluorescence-guided resection of malignant gliomas have a positive role in improving the radicality of malignant glioma resection.