RADIOENDOCRINE THERAPY OF BRAIN-TUMORS WITH THE LONG-ACTING OPIOID ANTAGONIST NALTREXONE IN ASSOCIATION WITH RADIOTHERAPY

Aims and Background: Malignant gliomas remain untreatable as the diffe rent therapeutic combinations are generally only palliative. Recent ex perimental evidence suggests that endogenous opioid peptides are invol ved in brain tumor growth. The aim of the present study was to evaluat e the effect on survival of concomitant administration of the long-act ing opioid antagonist naltrexone (NTX) in patients with malignant astr ocytomas treated with radiotherapy (RT). Methods: 21 patients with hig h grade malignant gliomas were randomized to receive RT alone or RT pl us NTX. The dose of RT was 60 Gy. NTX was given orally at a dose of 10 0 mg every other day without interruption until disease progression. R esults: The objective tumor regression rate in patients treated with R T plus NTX was higher than that of those treated with RT alone but not significantly so. On the contrary, the percentage of survivals at 1 y ear was significantly higher in patients treated with RT plus NTX than in those treated with RT alone (5/10 vs 1/11, P < 0.05). NTX therapy was substantially well tolerated in most patients. Conclusions: The fi nding of longer survival in brain tumor patients treated with RT plus NTX than in those who received RT alone suggests in vivo involvement o f endogenous opioid peptides in regulating the growth of malignant ast rocytomas.