New treatment protocol by intra-operative radiation therapy for metastatic brain tumours.

In patients with brain metastasis from lung cancer, we have been able to control local recurrence in approximately 80% of cases. But many of them tend to show brain atrophy with mental deterioration developing a few months after whole brain radiation. To prevent brain atrophy, we have attempted treating patients, whose metastasis was diagnosed as single, by intra-operative radiotherapy (IOR) alone following surgical resection. Among 43 patients, 19 patients who had no metastases other than the brain metastases, were chosen as subjects for active treatment (surgical resection+IOR). Their 1-year survival rate was 75%. Fourteen out of 27 patients with brain metastases from lung cancer received active treatment and their 1-year survival rate was 74%. This result was not inferior to our result of 71 patients who received surgical resection and whole brain irradiation. When no preventive whole brain irradiation was performed, patients were observed every 8 weeks by CT scan in order to ascertain tumour recurrence limited to the treated site or appearance of any new metastatic lesion remote from the treated site. Among all 43 patients, local recurrence was recognized in 7 cases and remote recurrence was observed in 7 cases. Within 6 months, local and remote recurrence was found in 3 cases each. These results were almost the same as those for the usual therapy (surgery plus whole brain irradiation). If such a new lesion is detected, additional radiation can be performed with the possibility of achieving complete remission.