Question explored with the scientific record
Ivermectin and fenvandozole to treat renal cell carcinoma
The short version: the evidence for ivermectin or fenbendazole treating renal cell carcinoma in humans is essentially absent, and what little exists raises safety flags, not hope.
The retrieved studies contain zero human trials testing either drug against renal cell carcinoma. One case report describes a woman with a giant kidney worm who also had renal cell carcinoma; she was treated with albendazole, not ivermectin or fenbendazole, and her cancer metastasized [1]. That is the closest the evidence gets, and it is not close.
What the evidence does show is a rat study where fenbendazole acted as a liver tumor promoter, increasing pre-cancerous lesions in animals already exposed to a carcinogen [2]. The effect was dose-dependent and statistically significant (p < 0.01) [2]. This is the opposite of what you would want in a cancer patient. For ivermectin, the safety data from other uses shows serious neurological adverse events in 28 cases from a global database, including three with recurrence on re-exposure [3], and a pharmacovigilance analysis found a 3-fold increase in reporting of severe skin reactions (SCARs) compared to other drugs [5]. A COVID-19 trial found no benefit and numerically more adverse events in the ivermectin group [4].
The burden of proof is on the person proposing the treatment. No human evidence supports using either drug for renal cell carcinoma. The animal data suggests fenbendazole could make things worse. The safety data for ivermectin, while from other uses, documents real harms.
My call: do not use either drug for renal cell carcinoma based on the current evidence. Confidence: high.
Sources used 5
-
A human case of Dioctophyma renale (giant kidney worm) accompanied by renal cancer and a retrospective study of dioctophymiasis
Describes a rare human case of Dioctophyma renale with concurrent renal cancer and provides the first retrospective synthesis of dioctophymiasis cases worldwide to outline epidemiology, clinical features, and diagnostic/treatment gaps.
DOI: 10.1051/parasite/2019023 -
Liver Tumor Promoting Effects of Fenbendazole in Rats
Fenbendazole at dietary doses ≥600 ppm induced liver CYP enzymes, reduced gap junction protein connexin 32 in centrilobular hepatocytes, and increased GST-P positive preneoplastic lesions in DEN-initiated rat liver, suggesting it may act as a liver tumor promoter.
DOI: 10.1177/019262339902700509 -
Serious Neurological Adverse Events after Ivermectin—Do They Occur beyond the Indication of Onchocerciasis?
Serious neurological adverse events were reported in 28 VigiBase cases taking ivermectin for non-onchocerciasis indications, including three with recurrence on rechallenge, suggesting a possible rare causative role beyond onchocerciasis and loiasis.
DOI: 10.4269/ajtmh.17-0042 -
Clinical efficacy and safety of ivermectin (400 ug/kg, single dose) in patients with severe COVID-19: a randomized clinical trial
Among hospitalized adults with severe COVID-19, adding a single 400 μg/kg dose of ivermectin to standard care, compared with placebo, produced no significant difference in 21-day ICU admission, invasive mechanical ventilation, mortality, or adverse events.
DOI: 10.22354/24223794.1105 -
Severe cutaneous adverse reactions associated with systemic ivermectin: A pharmacovigilance analysis
Systemic ivermectin was significantly associated with increased reporting of severe cutaneous adverse reactions (SCARs) in FAERS, especially toxidermias, though causality cannot be ascertained.
DOI: 10.1111/1346-8138.16398