Fenbendazole Cancer Self-Administered
When cancer patients self-administer drugs or dietary supplements, the medical community must be vigilant to ensure that such actions do not compromise their health. In this case, a patient with advanced non-small cell lung cancer (NSCLC) self-administered the antiparasitic drug fenbendazole. Although this drug is not approved for use in NSCLC, a number of Internet sites erroneously claim that it cured the patient’s tumor and that other patients have experienced similar results.
This claim was based on the fact that fenbendazole, also known as mebendazole, is an anthelmintic used to treat parasites such as roundworm and hookworm in animals. It works by cutting off the parasite’s supply of food by blocking a protein that binds to microtubules and inhibiting their polymerization. The drug can therefore collapse tubulin in the parasite, starving the parasite to death. Research into this class of antiparasitic compounds has indicated that they may have antitumor activity, and they are being studied for use in cancer treatment.
A recent incident in South Korea, where a patient with terminal pancreatic cancer claimed that he took anthelmintic medications including fenbendazole to cure his disease, raised the awareness of these agents and their potential as human cancer treatments. However, despite the fact that anthelmintics are widely used and have been tested in animal models, no peer-reviewed study has found evidence to confirm that these drugs can cure cancer in humans. Health Canada lists all anthelmintics as medications for veterinary use and does not recommend their use in patients with cancer.
Despite the fact that fenbendazole has chemical structures that resemble those of hypoxia-selective nitroheterocyclic cytotoxins/radiositizers and other antineoplastic agents, we have not previously tested its ability to sensitize tumor cells to radiation. We have now done so using EMT6 mammary tumor cells both in cell culture and as solid tumors in mice. In both cases, intensive doses of fenbendazole were able to cause significant cell death. However, the addition of fenbendazole to a radiation dose-response curve did not increase the sensitivity of the cells to radiation.
To test the hypothesis that fenbendazole may have a radiosensitizing effect on NSCLC, we examined the effects of fenbendazole in combination with radiotherapy. Three groups of mice were injected with fenbendazole (50 mg/kg/day, i.p.), or treated with a similar schedule of fenbendazole plus 10 Gy of x-rays, or untreated. The time to tumor volume measurements in each group are shown in Table 1. There was no difference in the time to four-fold tumor size between the fenbendazole and x-ray-plus-fenbendazole groups, nor were there differences in lung metastases or other toxicities of the drugs.
We also conducted a series of focus group interviews with NSCLC patients to understand their perceptions of fenbendazole cancer and the beliefs that led them to use it to treat their disease. The interviews were facilitated by an oncologist and included both men and women with various stages of NSCLC. The interviews were recorded and transcribed, and the data have been analyzed to identify common themes. fenbendazole cancer