A clinical trial for advanced cervico-vaginal pelvic carcinomas using californium CF-252 fast neutron therapy: Report of early responses

Californium-252 neutron brachytherapy combined with external pelvic radiotherapy plus concurrent chemotherapy for cervical cancer: a retrospective clinical study

“…NBT is a form of high-LET radiotherapy that has been shown to be effective in killing radio-resistant cancer cells [ 5 , 7 ]. In 1979, Maruyama et al [ 20 ] published the first therapeutic results of the application of 252 Cf NBT combined with external gamma-ray radiation for the intracavitary treatment of cervix cancer. Several studies have shown that 252 Cf NBT, as a treatment of cervical cancer, is significantly more effective than conventional low-LET irradiation [ 14 , 18 , 21 ].…”

“…The RBE of the neutron component of 252 Cf for the tumor tissue was estimated to be 6 [ 18 – 20 ]. The doses at point A were calculated assuming a high-dose-rate delivery of 6 Gy-eq for each patient per fraction, administered once per week, to deliver a total dose of 30 Gy.…”

Hypoxic Versus Normoxic External-Beam Irradiation of Cervical Carcinoma Combined with Californium-252 Neutron Brachytherapy

“…With the use of 252 Cf for intracavitary therapy, this combined procedure is influenced by the qualitatively different natures and effects of these two radiation types -high LET (intracavitary 252 Cf radiation) and low LET (gamma radiation, both external-beam and brachytherapy) -and is further influenced, during external-beam irradiation, by hypoxic conditions. The complexity of this new combined procedure was demonstrated for the first time in a clinical setting by Maruyama [16][17][18] and our clinical-experimental trial [32,33,36,40,41].…”

The role of the radiation oncologist in the management of gynecologic cancer

“…There has been a renewed interest in the utilization of radioactive needle implants to boost the radiation and remotecontrolled intracavity devices, e.g., Cathetron (TEM, United Kingdom), have been employed to provide intense local i r r a d i a t i~n .~~.~~ Attempts to overcome the relative radioresistance of hypoxic, potentially viable, tumor cells that may be more prominent in tumors with microscopic areas of necrosis, have included the utilization of hyperbaric oxygen,"' hypoxic cell sensitizers," and high linear energy transfer radiation^.^^ Ongoing clinical trials have suggested slight improvement in local control rates for patients treated with a combination of neutron and photon irradiation for locally advanced carcinoma of the cervix, when compared with external beam radiation utilizing photons alone.69 Intracavity placement of the neutron emitter Californium-252 has also yielded encouraging preliminary results. 68 Microwave-induced regional hyperthermia, in conjunction with external beam radiation therapy, has shown promise in a small series of patients with advanced cervical cance~s.~' Furthermore, very dramatic local tumor control rates in pelvic malignancies have been reported, utilizing radiofrequency induced local hyperthermia immediately preceeding interstitial radiation the rap^.^' The need for randomized controlled studies employing hyperthermia in conjunction with radiation therapy, is now manditory to substantiate these exciting preliminary findings.…”