Californium-252 (252Cf) versus Conventional Gamma Radiation in the Brachytherapy of Advanced Cervical Carcinoma

Abstract

The importance of neutron source (252)Cf in the brachytherapy of cervical carcinoma by overcoming the tumor resistance to conventional photon irradiation has been confirmed.

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

“…Comparative treatment results of our 5-year, randomized study show that the application of 252 Cf neutron radiation, with gamma radiation, in uterovaginal intracavitary therapy creates promising prospects for improvement in the cure rates of cervical carcinoma as a consequence of eradication of the part of the tumor cell population that is resistant to conventional photon radiation. This is supported by the observed result that one of the improved aspects of therapy outcomes was the significant decrease of local tumor recurrences in the small pelvis, in the near locality where 252 Cf neutrons interact with the primary tumor cells [34].…”

“…The treatment results were examined by comparing the 5-year survival rates of patients with cervical carcinoma treated intracavitarily by 252 Cf plus gamma radiation versus gamma-only radiation. This comparison strongly supported the role of neutron irradiation for significant improvement in the results of treatment [34].…”

Neutron Versus Photon Radiotherapy for Local Control in Inoperable Breast Cancer

“…While cells in mitosis and G2-phase are considerably more sensitive to photons than those in late S-phase [30], there is less variation in sensitivity to neutrons for cells in different phases of the cell cycle [34]. Also, as neutron irradiation has an oxygen enhancement ratio (OER) of about 1.6 and is less dependent on oxygen than photon irradiation, hypoxic tumor cells may be less radioresistant to neutrons [29]. The efficacy of fractionated radiotherapy is thought to be largely due to redistribution of cells in the cell cycle between fractions and reoxygenation.…”

Progress in Californium-252 Neutron Brachytherapy

“…The most important study is a randomized Phase III trial conducted by Tacev and colleagues from the Czech Republic [Tacev et al, 2003]. In that trial over 100 women with St IIb, IIIa, or IIIb received identical treatment with the exception that the initial brachytherapy was randomized between Cf-252 (6Gy-eq = 40 Gy) or CS/Ra.…”

“…These groups met several times in USA in 1985, 1990, and 1997 and exchanged their experiences with NBT. Great efficacy has been found for cervix cancers of all stages but most notable for the advanced stage III and bulky IB cancers [Maruyama et al, 1997;Tacev, et al 2003]. Endometrial adenocarcinomas and vaginal cancers [Maruyama et al, 1997] were also very curable with NBT.…”