An Estimate of the Patient Risk in Cyclotron Neutron Radiotherapy Using Mouse Testes As a Biological Test System

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

Section: Resultsmentioning

confidence: 99%

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

Laramore

Griffin

Gerdes

et al. 1978

Preliminary clinical results from U.S. fast neutron teletherapy studies

Parker

Berry

Caderao

et al. 1977

Over 700 patients with cancer have been treated with fast neutron beams since 1972 in three U.S. programs at the M.D. Anderson-TAMVEC (Houston and College Station, Texas), University of Washington (Seattle, Washington), and MANTA (Naval Research Laboratory, Washington, D.C.) , Clinical applications are about to start at the Fermilab (Batavia, Illinois) and Cleveland Clinic-NASA (Cleveland, Ohio). To date, studies have included: 1) effects of different treatment patterns and doses; 2) responses of several tumor types at many anatomic sites; and 3) acute and long-term normal tissue tolerances. Responses of several cancers, such as extensive epidermoid carcinoma of the cervix and ccfixed" metastatic cervical adenopathy, have been encouraging. In patients with glioblastoma multiforme, good tumor responses have not lengthened survival compared with that following conventional radiation therapy. Both local tumor control and "cure" have been compromised by the inclusion of patients with very extensive cancers. In general, treatment has been well tolerated. These preliminary studies provide the bases for planned clinical trials.

Fast neutron teletherapy for advanced carcinomas of the oral cavity and soft palate

Laramore

Griffin

Tong

et al. 1980

A retrospective study was performed to determine the efficacy of using fast neutron radiation for treating advanced squamous cell carcinomas of the oral cavity and soft palate. The majority of patients were judged to have less than a 10% 5-year survival with conventional medical treatment. Fifteen patients with oral cavity tumors were treated for cure with neutrons alone and six were treated with a combination of neutrons and photons as part of a mixed beam fractionation scheme. In the neutron-only group, the complete regression rate was 33% in the mixed beam group, the rate was 50%. Five patients who had squamous cell carcinomas of the soft palate were treated for cure, one with neutrons alone and four with a mixed beam regimen. The complete regression rate was 100%. The two-year NED results are comparable with literature results for more selected groups of patients with oral cavity and soft palate tumors treated by conventional photon therapy. The acute treatment morbidity was perhaps somewhat greater in the subgroup of patients treated with neutrons alone, and this subgroup later developed a more pronounced subcutaneous fibrosis. Morbidity associated with the mixed beam treatment regimen was comparable to that associated with conventional radiotherapy.