A review of californium-252 neutron brachytherapy for cervical cancer

Abstract

Since 1976 a clinical trial has been conducted to test the feasibility, the potential, and to develop methods for using the neutron‐emitting radioactive isotope, californium‐252 (Cf‐252), for the treatment of cervical cancer. A total of 218 patients were treated in the initial study period from 1976 until 1983. The trials initially treated advanced (Stages III and IV) cervical cancer patients using different doses and schedules; they were extended to include unfavorable presentations of Stages I and II because of favorable results in the initial trials. The authors began to treat patients with Stage IB bulky or barrel‐shaped tumors and the majority were treated with both radiation and hysterectomy. Actuarial survival was determined for Stage IB disease and was 87% at 5 years and 82% at 10 years. For those tested with preoperative radiation it was 92% at 5 and 87% at 10 years. For Stage II, it was 62% 5 years and 61% at 10. Survival 5 years after combined radiation and surgical therapy for Stage II disease was 68%. For Stage III, it was 33% at 5 years and 25% at 10. However, 5‐year survival using the early neutron implant was 46% versus approximately 19% for delayed Cf‐252 or cesium 137. Different schedules and sequences of neutrons and photons greatly altered outcome. Neutron treatment before external photon therapy was better for all stages of disease. Only about 5% of all patients developed complications after neutron therapy. No hematologic or mesenchymal second tumors were observed. Neutron brachytherapy was found to be very effective for producing rapid response and greatly improved local control of bulky, barrel, or advanced cervical cancers. The clinical trial identified and evolved schedules, doses, doses per session, and developed methods different from standard photon therapy but highly effective for local control and cure of cervical cancers of all stages. Clinical and radiobiologic understanding for the use of neutron therapy was greatly advanced by this trial. Future trials will focus on patients with advanced disease and will require evaluation of adjuvant chemotherapy studies and neutron‐enhancing chemicals.

Combination of external beam radiotherapy and Californium (Cf)-252 neutron intracavity brachytherapy is more effective in control of cervical squamous cell carcinoma than that of cervical adenocarcinoma

“…However, most patients had SCC; thus, randomized trials are needed to compare treatment effectiveness for cervical AC to improve AC therapeutic outcome. Furthermore, to treat local advanced stage of cervical cancer, combination of EBRT and ICBT with concurrent chemotherapy is considered as the optimal choice and the isotopes for ICBT most commonly used for ICBT of cervical cancer are c-emitting cobalt-60, cesium-137, and iridium-192 [17]. However, AC patients have usually an invasive disease of the uterine corpus causing the bulky tumor containing large number hypoxia cells [18,19].…”

Remote Afterloading for Neutron Brachytherapy Using Californium-252

“…The results of neutron brachytherapy treatment of cervical cancer and tumors of the oral cavity, using 252 Cf nuclide, show the potential to reach 80% local control of advanced tumors [4,5,9,11], as a consequence of breaking down the tumor resistance against conventional photon irradiation.…”

“…The discovery of californium-252 ( 252 Cf) nuclide [2,10], a source of gamma neutron radiation, featuring a neutron emission of 2.3 ϫ 10 12 s -1 g -1 and a mean energy of 2.10-2.37 MeV, established good conditions for using neutrons in tumor brachytherapy [5]. In contrast to teletherapy, brachytherapy makes an immediate interaction of neutrons and tumors possible, and, moreover, the economic and technical requirements connected with its introduction into clinical practice do not exceed those of conventional photon brachytherapy.…”

“…Since the mid-70s, the physical, dosimetric, clinical and radiobiological background for using 252 Cf nuclide in tumor brachytherapy has been gradually established, being confirmed by clinical application results [5]. The prospects of neutron brachytherapy were evaluated, on the basis of long-term results achieved in the treatment of tumors of the oral cavity and cervical carcinoma, during the "Californium-252 isotope for 21st century radiotherapy" workshop, held in Detroit, USA, in 1996 [12].…”

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].…”