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.

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 tumour) were treated with VAE pini (pine mistletoe) in progressively increasing doses (32) or with a sodium chloride solution (21) three times a week for 15 weeks. All horses were observed over a period of 12 months for tumour recurrence and cure. In an observational study (Study 2), 44 cats with fibrosarcoma, a very common skin tumour with a high rate of recurrence, were treated postoperatively with 0.1% (0.5 ml 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 cases (placebo: 14%), and cure was achieved in 28% of cases (placebo 14%). In Study 2, disease-free survival in cats treated postoperatively with VAE quercus was 438 days compared with 365–475 days for conventional chemotherapies and 120–261 days for surgery alone, as seen in the literature. Aggressive surgery combined with radiation and chemotherapy led to markedly superior results (661–986 days). Conclusion The results of the first study show that oral administration of mistletoe preparations also yields satisfactory prophylactic effects. The discussion surrounding oral treatment and the question of whether it can replace injection treatment must therefore be continued. The second study was able to demonstrate, for the first time, the efficacy of VAE compared to a 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.