The effects of PDT in primary malignant brain tumours could be improved by intraoperative radiotherapy

GBM has a poor survival despite surgery and chemoradiotherapy. Cytoreduction and PDT have postulated to afford better local GBM-control. However, the interaction of PDT with newer novel therapies had not been fully investigated. This study reviewed the impact of PDT in conjunction with intraoperative radiotherapy.

Case note review of prospectively collected data of GBMs treated surgically by the senior author (SE). Patients received standard therapy (ST), ST+PDT or ST+PDT+IORT. ST involved maximum safe resection, PDT involved intracavity 100 J/cm² 630 nm laser and IORT involved intracavity 10-15 Gys using the PRS400®. Patients were followed up clinically and radiologically till death.

There were 73 patients included in this analysis (42 males). The average age was 59years. Thirty received PDT and 43 did not. The mean survival of PDT-patients was significantly longer than those had ST alone (62.9 weeks vs. 20.6 weeks) (p=0.001). Patients < 65 year of age survived longer than those ≥ 65 year (p=0.033). IORT on its own did not make a significant difference to survival (p=0.111). However the average survival for patients who received PDT+IORT was substantially higher than those who received PDT alone (79 weeks vs. 39.7 weeks). Using a Cox regression covariant analysis, demonstrated that PDT was the only therapy to make a statistically significant difference to survival (p=0.018).

PDT in high grade glioma was statistically significant therapeutic modality and its effects were further improved by IORT.