Can Ivermectin Treat Intestinal Tumors in Dogs?

Can Ivermectin Help a Dog with Metastatic Leiomyosarcoma?

“I have a 14-year-old Lhasa Apso diagnosed with metastatic reactive jejunal lymph nodes. Jurema has a tumor in her intestine/colon. I found you talking on pethelpful.com about ivermectin in dogs with cancer. I want to know if ivermectin is an option to treat her? If yes, I would like to know the recommended dosage. She is 6.2kg (13.66 lbs). I have attached her lab results.” – Marcelo

After looking at your dog’s lab results, it appears there are several things going on here. The first is the tumor in the intestine, most likely a type of smooth muscle cancer called leiomyosarcoma. There are also several lymph nodes that are swollen and appear to be infected or growing because of metastasis from the primary tumor. The last problem noted is the potential cancer on Jurema´s right adrenal gland. Since you did not include her symptoms, I am not sure if the adrenal gland problem is a functional or non-productive tumor.

Treating Intestinal Tumors in Dogs

The conventional and most successful treatment for dogs with this type of cancer is surgical removal. If the cancer has already metastasized to the regional lymph nodes, however, there are most likely other cancer cells in other areas, and removing the main tumor will probably not increase her lifespan.

There is no evidence that ivermectin is going to help treat your dogs leiomyosarcoma. In humans, however, it has been found that ivermectin increases cell death (aptosis) in rectal cancer. (1) That is no guarantee that it is going to increase the cell death of the cancer in your dogs intestine, but we do know that even with conventional treatments, the expected lifespan after diagnosis with this kind of cancer is 10 months or less. (2)

Because it has metastasized, and because of her anemia, I do think it is worth trying ivermectin.

If your regular veterinarian has recommended surgery, that is the best option for her to last more months. If she is unlikely to survive the procedure, however, you may be able to extend her life with an alternative treatment like ivermectin.

Is there any evidence that ivermectin is going to help your dog with this kind of cancer? No, but it is possible. Ivermectin has been found to help in some cases of rectal cancer in humans, and although it may damage the adrenal glands in some animals, it only does so at very high doses (2000 micrograms per kilogram, whereas the dose for cancer therapy is 200 micrograms per kilogram), so it should have no negative effects. (3)

Ivermectin Dosage

If you want to try and use the ivermectin to extend your dog’s lifespan, please follow this dosage chart. The amount given in each dose is small, only about 200 micrograms per kilogram of body weight, and is substantially less than any amount that is going to cause toxicity problems with a dog. (A much higher dose was used in rodents in some of the studies. Those doses would be fatal to some dogs.)

For a small dog like Jurema, the sheep drench product will be ideal, as she will be getting about 1.5 cc of the sheep product. If you do not have that form available and Amazon does not ship that to Panama, let me know what strength ivermectin you have available, and I will figure out her dose.

Diet for Dogs with Cancer

I also recommend you switch her diet to this recipe for food for dogs with cancer. Cancer cells grow rapidly and consume a lot of glucose, which is produced in high levels from the dry dog foods. The ketogenic diet produces ketones as an energy source, and her glucose levels will fall, slowing down the cancer growth rate. I want to emphasize that if for some reason she will not eat this diet, then just go back to her regular food. Cachexia is a serious problem in dogs with cancer, and it is not always easy to switch their diet while they are ill. If she decides that she only wants a certain food, it is better than letting her go hungry.

Sources

1. Tang M, Hu X, Wang Y, Yao X, Zhang W, Yu C, Cheng F, Li J, Fang Q. Ivermectin, a potential anticancer drug derived from an antiparasitic drug. Pharmacol Res. 2021 Jan;163:105207. doi: 10.1016/j.phrs.2020.105207. Epub 2020 Sep 21. PMID: 32971268; PMCID: PMC7505114. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7505114/
2. Kapatkin AS, Mullen HS, Matthiesen DT, Patnaik AK. Leiomyosarcoma in dogs: 44 cases (1983-1988). J Am Vet Med Assoc. 1992 Oct 1;201(7):1077-9. PMID: 1429139. https://pubmed.ncbi.nlm.nih.gov/1429139/
3. Hasan, Bushra. EFFECT OF DIFFERENT DOSES OF IVERMECTIN ON BIOMARKER HORMONE OF ADRENAL GLAND AND HISTOLOGY OF IT IN LOCAL FEMALE RABBITS. International Journal of Applied Sciences and Technology, 2022. https://www.minarjournal.com/dergi/effect-of-different-doses-of-ivermectin-on-biomarker-hormone-of-adrenal-gland-and-histology-of-it-in-local-female-rabbits20221202024312.pdf

This article is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from your veterinarian. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.

© 2024 Mark dos Anjos, DVM