Abstract
In order to evaluate the effectiveness of radiation therapy for metastatic brain tumors, 62 patients with metastatic brain tumor were studied by means of computed tomography (CT) scans during and subsequent to radiation therapy. Results were as follows: After therapy there was complete remission in 23% of patients (14/62), partial remission in 42% (26/62), minor remission in 19% (12/62), and no change in 16% (10/62). None of the patients showed an increase in size. The response rate of the various histological types of lung cancer was 90% (9/10) in undifferentiated carcinoma, 56% (10/18) in adenocarcinoma, and 33% (1/3) in squamous cell carcinoma. In patients who showed a decrease in the tumor size at the completion of radiation therapy, more than a 50% reduction in the tumor size was often obtained with a dose of 20 to 40 Gy. In the follow-up CT after radiation therapy, a delayed effect was observed in 23 out of 35 patients (66%). The delayed effect was generally noted during the first 3 months after completion of radiation therapy. The result suggests that timing of the CT evaluation is very important for observing the effect of radiation therapy and additional new therapeutic methods. The response rate was 36% in 25 patients treated by radiation alone and 49% in 37 patients treated by radiation combined with chemotherapy, although statistically not significant. Improvement of neurological findings was noted in 47 patients (76%), and clinical response seemed to correlate with response in CT. Thirty-one patients died of cancer. Twenty-two of the 31 died of advancing systemic cancer without recurrence of brain lesion. Death from progressive brain lesion resulted in only 29% of the patients. This shows that the length of survival is not an appropriate indicator of therapeutic efficacy.
The results in this series suggest that serial CT scan is the best objective way to evaluate treatment and that the majority of patients with metastatic brain tumor have benefited from radiation therapy.
