Can You Use Fenben for Cancer?
Recently, posts on social media have been making the rounds claiming that a deworming medication used on dogs can cure cancer in humans. This claim is based on an anecdotal account from an unlicensed veterinarian, Andrew Jones, who claims that fenbendazole (FZ) cured his small-cell lung cancer and prevented metastases in his brain and liver. This report has been widely disseminated, including on TikTok and Facebook. Despite the fact that several research studies have found that fenbendazole can slow down cancer growth in cell cultures and animals, there is no evidence at present that it can cure cancer in people. In order to arrive at such a conclusion, randomized controlled trials involving large numbers of patients need to be performed first.
FZ is a moderate microtubule targeting agent, causing mitotic arrest and thereby promoting cancer cell death. It also induces p53 to a high level in human cancer cells and inhibits glucose uptake by downregulation of GLUT transporters and hexokinase II. It thus has anti-neoplastic properties, which can be enhanced by other cellular effects that are mediated by p53, such as mitochondrial translocation and induction of autophagy.
The efficacy of fenbendazole in a radiosensitization assay was evaluated by treating EMT6 cell monolayers with a series of doses of irradiation under aerobic and hypoxic conditions. The radiation dose-response curves were normalized to the unirradiated control and plotted against the concentration of FZ in the culture at the time of irradiation. Treatment with fenbendazole did not significantly alter the radiation response either under aerobic or hypoxic conditions.
Severe hypoxia increased the toxicity of 2-h treatments with FZ to EMT6 cell monolayers, but not to fibroblast cultures. However, the survival curves for monolayers treated with varying doses of FZ over 24 h were similar to those for controls. Survivals were plotted as surviving fractions and yield-corrected surviving fractions.
Acute oral administration of FZ to mice bearing xenografted A549 tumors resulted in a significant decrease in tumor volume, weight and metastases (Fig. 9). This was accompanied by a reduction in tumor vascularity, measured by spectrophotometrically measuring hemoglobin content in the tumors.
The data suggest that a combination of the cytotoxic effects of fenbendazole with those of other drugs that are active in hypoxic environments could improve cancer therapy. However, because of the wide availability of other nitroheterocyclic chemotherapeutic agents that act as hypoxia-selective radiosensitizers and because it is not clear how this effect would be augmented by the presence of a hexokinase inhibitor, additional research will be needed to determine whether the combination approach can be further improved. FZ is a promising candidate for this purpose, since it has a unique and novel mode of action that may enhance the anti-neoplastic activity of other radiosensitizers. Furthermore, its moderate toxicity in normal mice and the lack of gastrointestinal toxicity make it a potentially safer alternative to other hypoxia-selective cytotoxic agents. This study was funded by the Basic Science Research Program through the National Research Foundation funded by the Ministry of Education. fenben for cancer