Dogs, like this Labrador Retriever, can sometimes detect cancer.

Can dogs detect cancer? In 2006, acupuncturists at the Pine Street Clinic, St. Anselmo, CA, published a pioneering study titled “Diagnostic Accuracy of Canine Scent Detection in Early- and Late-stage Lung and Breast Cancers.” In it, they demonstrated that a dog’s nose is the most sensitive tool known for the detection of cancer cells. On my last visit, two of the dogs in question were the resident deities of Pine Street, and although on incredibly long leashes, more or less had the run of the place.

“Recent research suggests that dogs can detect scent in the measure of one part per trillion,” Nicholas Broffman, son of the clinic’s co-director, Michael Broffman, LAc, told me. Nicholas is the executive director of their nonprofit foundation. “Because of the foundation’s cancer research and the clinic’s work with cancer patients, that is what we’ve turned into a specialty. So how do you give cancer patients hope? Early detection, because the earlier you detect cancer, the more options you have, anxiety is less and treatment options are better. So we asked ourselves, how can you catch cancer even earlier?”
Pine Street then asked Prof. Tadeusz Jezierski, of the Institute of Genetics and Animal Breeding of the Polish Academy of Sciences, to conduct further research on dogs’ scent detection. “We wondered if there was a biomarker, some kind of signature to cancer cells,” said Nicholas. “We set out to look for a device to test for such a thing, and it turns out that it is the dog. There is no technology that even comes close” (references at end).
Their double-blind study showed that cancer cells convey a scent signature in the patient’s breath, possibly through the decay of cancer cells. These chemicals (not all of which have been identified) can then be “sniffed out” before tumors are found through current scanning equipment such as x-rays and CAT scans.
This theory was confirmed in a 2011 article in the journal, Gut. In this study, a trained Labrador retriever’s sniffing ability was 99 percent accurate and equaled the most sophisticated diagnostic equipment! “A specific cancer scent does indeed exist and that cancer-specific chemical compounds may be circulating throughout the body,” Fukuoka researchers wrote. “These odor materials may become effective tools in CRC [colorectal cancer, ed.] screening.” Dog-based detection was highly sensitive even for early-stage cancers and was not confounded by current smoking, benign colorectal disease or inflammatory disease. This study was a powerful confirmation of the Pine St. Clinic’s once controversial findings.

In March 2012, doctors in Stuttgart published a study in which trained dogs were able to detect lung cancer with a sensitivity of 90 percent and a specificity of 72 percent. This study involved 60 lung cancer patients and 110 healthy controls, and included 50 patients with non-malignant lung disease. These findings also powerfully corroborated the Pine Street results. The high accuracy of canine scent detection of lung cancer, Michael Broffman told me, suggests dogs might, in the future, make a contribution to successes in lung cancer screening and detection. In 2015, the Polish authors wrote:

“The canine method has some advantages as a potential cancer-screening method, due to its non-invasiveness, simplicity of odor sampling and storage, ease of testing and interpretation of results and relatively low costs.”

I, for one, would rather have a “dog scan” than a “CAT scan.”


(McCulloch, Michael, Tadeusz Jezierski, Michael Broffman, Alan Hubbard, Kirk Turner, and Teresa Janecki. “Diagnostic Accuracy of Canine Scent Detection in Early- and Late-Stage Lung and Breast Cancers.” Integrative Cancer Therapies 5, no. 1 (March 2006): 30–39. doi:10.1177/1534735405285096); Sonoda, Hideto, Shunji Kohnoe, Tetsuro Yamazato, Yuji Satoh, Gouki Morizono, Kentaro Shikata, Makoto Morita, et al. “Colorectal Cancer Screening with Odour Material by Canine Scent Detection.” Gut 60, no. 6 (June 2011): 814–19. doi:10.1136/gut.2010.218305; Ehmann R, Boedeker E, Friedrich U, et al. Canine scent detection in the diagnosis of lung cancer: revisiting a puzzling phenomenon. Eur. Respir. J. 2012;39(3):669–676; Jezierski, Tadeusz, Marta Walczak, Tomasz Ligor, Joanna Rudnicka, and Bogusław Buszewski. “Study of the Art: Canine Olfaction Used for Cancer Detection on the Basis of Breath Odour. Perspectives and Limitations.” Journal of Breath Research 9, no. 2 (June 2015): 027001. doi:10.1088/1752-7155/9/2/027001)