Shrinking Dog Tumors Nonsurgically

Shrinking dog tumors nonsurgically

Project Summary: Shrinking Dog Tumors

Please note: Non-surgical methods such as calcium chloride to reduce the size of non-cancerous tumors or lipomas are considered experimental and should be used under the care of a veterinarian.

An injection of calcium chloride solution has been shown to reduce the size of benign tumors in dogs. Other chemical solutions and noninvasive methods have also been used successfully in canine and human patients. Initial reports shows promise in shrinking tumors in dogs without surgery, but more research is needed to develop methods that avoid complications and standardize practice. This site includes basic information on these techniques, as well as non-surgical treatments for cancer in animals.

  • If you are interested in using calcium chloride for benign tumor reduction in your dog, please consult with your veterinarian and share information from this page. Keep in mind that most veterinarians are not familiar with these methods. If your pet has been diagnosed with a cancerous tumor, you can look for a veterinary oncologist to determine the best treatment option for your pet.
  • If you are a veterinarian who has used non-surgical methods of treating benign tumors, please contact us and consider listing your clinic in our Veterinarian Directory.
  • Mammary tumors and benign masses are common in older dogs and other pets.
  • Large tumors can restrict movement, cause pain, and even rupture (especially when licked or rubbed).
  • Common treatment involves surgery, which is not recommended for many older animals and not practical in some environments.
  • A nonsurgical treatment for tumors would provide an option for pets that cannot undergo surgery or in low-resource or remote settings.
  • Injection of a necrotizing chemical, such as calcium chloride solution, has been shown to reduce the bulk of tumors.
  • More research will help to elucidate differences between chemical solutions and to develop best practices.
  • Parsemus Foundation supports the use of low-cost, noninvasive treatments for pets and encourages veterinarians to consider offering these treatments and sharing experiences. 

Project Topics

Tumor bulk reduction

Older dogs often get mammary tumors and benign (not cancerous) masses. Though benign, these lumps can cause problems if they get very large or start to restrict movement. They can be surgically removed, but this is not an option for many older dogs due to the risk of anesthesia and recovery.

Calcium chloride dihydrate solution, which is used as a testicular injection to shrink the testes for nonsurgical neuter, may be an option for shrinking dog tumors (or tumor bulk reduction). The first known report of this use was in 1977 by Koger. Besides allowing veterinarians to offer their clients an anesthesia-free treatment for older dogs, calcium chloride solution has the advantage of being made from readily available ingredients and thus being an option for use in exceedingly low-resource or remote settings. It provides an option for treating animals that otherwise wouldn’t get treated.

Mammary tumor reduction in older dog using injection of calcium chloride

A case study using 0.3-0.5 ml injections of alcohol and 20% calcium chloride in alcohol was successful in reducing the bulk of a mammary mass on the abdomen of an older female dog by 75%. The study was presented in 2011.

Bunny Tumors
Left: Mammary tumor before treatment; Center: Inflammation that occurred after calcium chloride injection, which subsided within 2 weeks; Right: Reduction in size of tumor following treatment.

Veterinarians can order the solution from a sterile-filling-capable compounding pharmacy by requesting “20% (w/v) Calcium Chloride Dihydrate, USP in Ethyl Alcohol 190 proof, USP.” It is important not to inject too much calcium chloride solution. It works by to killing tissue it comes into contact with. Side effects including dry abscesses or skin necrosis can occur if it is injected into healthy tissue. Additionally, larger tumors will likely require repeated treatments.

Treatment of lipomas (fatty tumors)

Calcium chloride has been used to reduce the size of lipomas, which are fatty tumors. Albers and Theilen (1985) published a study using 10% calcium chloride injected into the subcutaneous lipomas of 10 dogs. The authors reported that six months later, four tumors had disappeared and 14 were less than 50% of their original size. However, skin necrosis over the tumor developed in three dogs.

A higher concentration of calcium chloride is likely counterproductive. Our experience using 20% calcium chloride in alcohol in a lipoma resulted in complications. By 24-48 hours after the injection, the mass may be shrunk by half, but the skin ruptured, creating a draining wound that had to be treated with antibiotics. Severe complications may require surgical excision. It may be that the body cannot absorb the lipoma adequately using the 20% calcium chloride, but more research is needed to clarify this issue.

Other nonsurgical injections to treat lipomas have been attempted. A study in 2005 by Rotunda and colleagues evaluated deoxycholate, a bile salt, to treat lipomas in human patients. They reported an average of 75% reduction in tumor size after 2 or more injections, and concluded that this injectable treatment might be useful for small lipomas, but that further research was needed. Steroid injection at a dose of 40 mg/mL was also used to treat lipomas in dogs (Lamagna et al., 2012). Nine of 15 tumors showed a complete regression, with shrinkage in the remaining dogs with only minor complications.

New noninvasive methods used for human fat removal may one day be applied to dog lipomas. Cryolipolysis (“CoolSculpting”) applies cool temperatures to fat cells, which break down when exposed to extreme cold. Radiofrequency (“Vanquish”) or light therapy (“Sculptsure”) both work by heating fat cells to kill them.

Non-surgical treatment of cancerous tumors in pets

A number of non-surgical methods for removing or reducing the size of cancerous tumors are currently being used in humans and some are available for dogs and other pets. Chemotherapy, radiation therapy, immunotherapy, and cryotherapy are non-surgical treatment options that might be appropriate for some cancers. There is also a FDA approved treatment for dogs with nonmetastatic mast cell tumors (a common skin cancer) by injecting tigilanol tiglate (Stelfonta) into the tumor.

Having a pet diagnosed with cancer can be scary and confusing. A veterinary oncologist can help you to determine the best treatment options for your pet. Your primary veterinarian will usually give you a referral to the nearest veterinary oncologist, or you can use the search tool on the Veterinary Cancer Society page.

Take Action on Shrinking Dog Tumors

While calcium chloride in alcohol and several other chemicals appear to be effective in reducing the size of certain benign tumors, more research will help to quantify results and evaluate options for lipomas.

If you are a veterinarian who offers calcium chloride or other injectable tumor reduction treatments, please sign up for our Veterinarian Directory and let us know of your experience. If you are interested in collecting research data on the use of calcium chloride solution for tumor bulk reduction, please contact us.

If you are a pet owner who is looking for nonsurgical tumor reduction options, please provide the information on this webpage to your own veterinarian to determine if a nonsurgical injection is a good option to treat tumors on your pet. Keep in mind that this work is experimental, and not all veterinarians will be interested in trying it.

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  • Albers GW, Theilen GH, 1985. Calcium chloride for treatment of subcutaneous lipomas in dogs. J Am Vet Med Assoc 186(5):492-4. (Abstract)
  • Brown GK, Finlay JR, Straw RC, et al. 2022. Treatment of multiple synchronous canine mast cell tumours using intratumoural tigilanol tiglate. Frontiers Vet Sci (Free full text)
  • Lamagna B et al., 2012. Canine lipomas treated with steroid injections: Clinical findings. PLoS One. 7(11): e50234. (Free full text).
  • Lissner E, Montilla H, Kutzler M, 2011. Intralesional injection of calcium chloride dihydrate in alcohol for minimally-invasive bulk reduction of a mammary mass. (Poster download)
  • Koger, LM, 1977. Item #451 of the Annual Meeting of the American Society of Animal Science, University of Wisconsin, July 24-27, 1977. (Abstract)
  • Koger, Nov 1977. Calcium Chloride, Practical Necrotizing Agent. J Am Assoc Bovine Pract 12:118–119. (Free full text)
  • Rotunda AM, Ablon G, Kolodney MS, 2005. Lipomas treated with subcutaneous deoxycholate injections. J Am Acad Dermatol 53(6):973-8 (Abstract)

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