9 - Radioisotopes in the Treatment of Ovarian Cancer

Abstract

Ovarian cancer, currently, is the leading cause of death from malignancies arising in the female genital tract. Investigators and collaborative groups are focusing on this problem in an attempt to improve patient survival. The material reviewed has attempted to gather the data that relate to the use of radioisotopes in the treatment of ovarian cancer. The conclusions reached from this review are: Dose. The initial therapeutic dose of 198Au was empirically determined by Muller. This empirically determined dose was then used to estimate a dose of 32P, based on certain assumptions about these radiocolloids that have been shown to be erroneous. It would appear that the administered dose of 100-150 mCi of 198Au yields a significantly greater tissue dose than 10-15 mCi of 32P. Complications. Complications associated with 198Au are a result of a possibly excessive dose, delivered over a shorter period of time, with a significant gamma component. It is clear that in greater than 99 per cent of disintegrations each beta particle is associated with a gamma component. Distribution, dose distribution, and dose rate. These three critical factors have recently been evaluated for intraperitoneal 32P. It would appear that distribution is non-uniform, and thus dose distribution is not homogeneous, and that dose rate is low and may be ineffective in controlling ovarian cancer. Results of treatment. It would appear from a review of the literature that no prospective randomized well-controlled study as indicated the effectiveness of 32P over other treatment modalities. There is only circumstantial evidence for its effectiveness. The clinical applicability of 32P in the treatment of Stage I ovarian cancer, as part of a treatment protocol, awaits the results of well controlled prospective clinical trials.