Recent videos on TikTok, Facebook, and YouTube have promoted a deworming medication for dogs as a cure for human cancer. The videos are based on the story of a woman who claims that taking oral fenbendazole, marketed as an anthelmintic for dogs, reduced her cancer progression following a diagnosis of stage three lung cancer. This story has been disproven by a team led by Sheila Singh, Director of McMaster’s Centre for Discovery in Cancer Research.
Singh’s team performed multiple experiments to determine whether the antihelmintic fenbendazole would reduce the growth of EMT6 tumors and inhibit radiation-induced growth arrest in the same way that it does in mice. In a series of three experiments, tumor-bearing BALB/cRw mice were stratified by tumor volume at the point shown by the dark arrows and treated with either a control diet, fenbendazole, or fenbendazole plus 10 Gy of radiation. The growth of the unirradiated tumors was similar to that of the controls, and the irradiated tumors were indistinguishable from those of the fenbendazole group.
In vitro, fenbendazole had cytotoxic and cytostatic effects on the cell culture model of EMT6 tumors at high concentrations and long incubation periods. Survival curves were steep at low drug concentrations and plateaued at higher doses, as determined by colony formation assays. Severe hypoxia increased the toxicity of 2-h treatments of cells with fenbendazole.
In addition, fenbendazole reduced the proliferation of the EMT6 mammary tumors in mice, but did not affect the growth of nontumorous mouse mammary tumors in the same mice. The antitumor effects of fenbendazole were not enhanced by the combination of fenbendazole and radiation or with the antineoplastic agents docetaxel or carboplatin, which both have mechanisms of action that overlap with those of the antihelmintic. fenbendazole cures cancer
