Fast neutron and mixed (neutron/photon) beam teletherapy for grades III and IV astrocytomas

Abstract

A study was performed in order to assess the efficacy of using fast neutron irradiation, either alone or in conjunction with megavoltage photons, in treating Grades I11 and IV astrocytomas. The study encompasses fifteen patients with Grade I11 lesions and twentytwo patients with Grade IV lesions.Various fractionation schemes are described. Only one patient is still alive at the present time. Regarding the other patients, the mean survival after completing therapy was 10.8 months for those patients with Grade I11 lesions and 7.5 months for those patients with Grade IV lesions. Particularly for Grade I11 lesions, the average survival was appreciably less than that of patients treated with photons alone. The treated patients also had no noticeable improvement in quality of survival when compared with the results of conventional photon irradiation. There was no appreciable difference in survival between the group treated with neutrons alone or with mixed (neutrodphoton) irradiation. Autopsy data on fifteen patients showed gross tumor progression in only one instance, and this patient also had liver metastases. In the other fourteen cases, the gross tumor volume was replaced by coagulation necrosis. In general, there were some abnormal cells intermixed with the regions of coagulation. These cells are currently felt to be reactive astrocytes. Both a diffuse gliosis and a white matter demyelination were found in regions far from the tumor volume and this presumably is related to the ultimate cause of death.Cancer 42:96-103, 1978.RADES 111 A N D IV ASTROCYTOMAS~ are per-G haps the most malignant of the intracranial neoplasms. These lesions tend to be highly infiltrating in character and in general cannot be completely removed surgically due to the close proximity of vital brain areas. Postoperative megavoltage photon radiation therapy has been routinely given to try to eradicate any tumor left behind, and although

A randomized study of misonidazole and radiotherapy for grade 3 and 4 cerebral astrocytoma

“…Clinical studies using alternative techniques to overcome the potential problem of hypoxia in gliomas, such as hyperbaric 02 (Chang, 1977) and fast-neutron therapy Laramore et al, 1978;Batterman, 1980;Catterall et al, 1980), have not demonstrated any improvement in survival over comparable patients treated by photons. There was, however, some reported improvement of local tumour control at postmortem examination.…”

Fast neutron therapy for malignant astrocytomas

“…Since malignant gliomas present a significant problem in oncologic management, many investigators have utilized new and experimental approaches. Preliminary studies (19)(20)(21) with fast neutrons in the treatment of malignant gliomas revealed the efficacy of neutrons in eradicating these tumors. However, survival was unchanged since patients were dying of, possibly, treatment related problems.…”

“…Preliminary results from Hammersmith (19) and the University of Washington in Seattle (20,21) indicate that fast neutron radiotherapy has the potential for eradicating high grade tumors in the brain. In a controlled pilot study Catterall et al (19) have treated 30 patients with fast neutrons and 33 patients with conventional photon radiation therapy between 1973 and 1976.…”

“…The hypoxic cell population is thought to be less responsive to the effects of conventional photon radiation since the presence of oxygen is important for the effects of low-LET (linear energy transfer) ionizing radiations. Attempts to improve the killing of hypoxic cells have involved the use of hyperbaric oxygen (13), hypoxic cell sensitizers (14)(15)(16)(17)(18) and high-LET radiation (19)(20)(21)(22). High-LET radiation such as neutrons or pi-mesons have been used alone and combined with conventional radiation.…”

Reirradiation for recurrent cerebral astrocytoma

“…It has been difficult to determine precisely the incidence of cerebral radiation injury since computed tomography (CT) and clinical examination are suboptimal methods for detecting this process. Radionecrosis has been estimated to occur in 3-10% of patients receiving irradiation for primary brain tumors [10][11][12][13]. Recently, magnetic resonance imaging (MR) has shown promise in assessing subtle or small areas of radiation damage in the normal brain; this method is more sensitive than CT or clinical examination in detecting radiation-induced injury [14].…”