Using Viscum album extracts (ISCADOR) for successful management of neoplasms of the skin in horses and cats in consideration of aspects relevant to human medicine.

Summary

Background: Mistletoe extracts (Viscum album extracts, VAE) such as ISCADOR, have been used successfully in human oncology for many years. In veterinary medicine, there have been reports of successful treatment, but scientific data on efficacy are lacking. Two studies were therefore conducted to assess whether VAE can serve as an adjunct to standard treatment in horses and cats.
Methods: As part of a placebo-controlled double-blind study (study 1), 53 horses with equine sarcoid (a solitary or multifocal skin tumor) were treated with VAE pini (pine mistletoe) in progressively increasing doses (n=32) or with a sodium chloride solution (n=21). Three times a week for 15 weeks. All horses were observed over a period of 12 months for tumor recurrence and cure. In an observational study (study 2), 44 cats with fibrosarcoma, a very common skin tumor with a high rate of recurrence, were treated postoperatively with 0.1% (0.5ml per dose) oral VAE quercus (oak mistletoe) twice daily, and disease free survival was measured.
Results: In study 1, treatment with ISCADOR led to significantly better results than placebo. Improvement was seen in 41% of the cases (placebo 14%), and cure was achieved in 28% of the cases (placebo 14%). In study 2, disease-free survival time in cats treated postoperatively with VAE quercus was 438 days compared with 365 to 475 days for conventional chemotherapies and 120 to 261 days for surgery alone, as seen in literature. Aggressive surgery combined with radiation and chemotherapy led to markedly superior results (661 to 986 days).
Conclusion: The study 1 was able to demonstrate, for the first time, the efficacy of VAE compared to placebo control. This study also showed that the effect of VAE apparently extends considerably beyond the treatment period; unexpectedly, only very few recurrences were observed between the end of treatment and the 12th month of observation. The results of the study 2 show that oral administration of mistletoe preparations also yields satisfactory prophylactic effects. The discussion surrounding oral treatment and the question whether it can replace injection treatment must therefore be continued, even in human medicine.