There are nearly 90 million pet dogs in the United States, and unfortunately, about one in four will develop cancer during their lifetime. As more pet owners seek treatment for their dogs, veterinarians are administering a variety of different chemotherapy drugs. These drugs are hazardous to humans, destroying both cancer cells and healthy cells, leading to potential health risks when undergoing treatment as well as from dermal contact with residual drugs.

In a novel study from the University of Minnesota School of Public Health (SPH), researchers have uncovered evidence that chemotherapy drugs leave behind contamination that could potentially harm not only the estimated 315,000 Americans who work in veterinary settings, but also millions of Americans who live with domesticated dogs.

To conduct the study, the research team developed a new, highly sensitive testing method using liquid chromatography–mass spectrometry to detect trace levels of six common chemotherapy drugs on clinic surfaces and animal fur. Samples were collected from surface areas at the UMN Veterinary Medical Center after canine chemotherapy treatments, as well as from the coats of dogs undergoing treatment in clinic and home environments.

Published in Annals of Work Exposures and Health, the study provides the first comprehensive look at how cancer treatments for dogs can expose workers and pet owners to these drugs in different settings. Key findings include:

• Two chemotherapy drugs were found in several areas of the veterinary oncology clinic.  Cyclophosphamide and doxorubicin were detected on frequently touched clinic surfaces such as door handles, treatment tables, and drug preparation areas directly after treatment administration. The same drugs were also found on kennel surfaces, floors, and floor mats several hours after treatments took place.
• One chemotherapy drug was found on the fur of most dogs post treatment. Cyclophosphamide was found on 80% of the bodies of dogs five hours post treatment. One dog showed levels of contamination 24 post treatment after returning to its home.

“As chemotherapy is increasing for both human and veterinary patients, there is a greater risk for potential hazardous exposures from contact with these drugs for workers in clinics and caregivers in homes,” said Andrew Floeder, SPH researcher and lead author. “The new method we developed gives us the ability to detect trace amounts of these drugs anywhere they are administered, from clinical surfaces to dogs’ coats, helping us understand where contamination happens and how to better protect both clinical staff and pet owners in the future.”

The study recommends expanded environmental monitoring, training for clinic staff, and clear safety guidance for pet owners. The authors also recommend that future research explores effective decontamination strategies and assesses new areas of contamination in home environments.