Although more "toxic" than unwrapping at the tumor via enzymes, systemic Colchicine is a common gout medication available in pill form. My father took it for years.
Another version of the current news article:
http://www.guardian.co.uk/science/20...r-side-effects
Research investigating Colchicine to reduce negative cancer related effects of surgery:
http://www.jci.org/articles/view/34279
Less recent research from 1950
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2038695/