Dogs Can detect Cancer

ScienceDaily (Feb. 8, 2011) — In the February 2011 issue of European Urology, Jean-Nicolas Cornu and colleagues reported the evaluation of the efficacy of prostate cancer (PCa) detection by trained dogs on human urine samples.

In their article, the researchers affirm that volatiles organic compounds (VOCs) in urine have been proposed as cancer biomarkers. In the study, a Belgian Malinois shepherd was trained by the clicker training method (operant conditioning) to scent and recognize urine of people having PCa. All urine samples were frozen for preservation and heated to the same temperature for all tests. After a learning phase and a training period of 24 months, the dog's ability to discriminate PCa and control urine was tested in a double-blind procedure.

Urine was obtained from 66 patients referred to an urologist for elevated prostate-specific antigen or abnormal digital rectal examination. All patients underwent prostate biopsy and two groups were considered: 33 patients with cancer and 33 controls presenting negative biopsies. The dog completed all the runs and correctly designated the cancer samples in 30 of 33 cases. Of the three cases wrongly classified as cancer, one patient was re-biopsied and a PCa was diagnosed. The sensitivity and specificity were both 91%.

This study shows that dogs can be trained to detect PCa by smelling urine with a significant success rate. It also suggests that PCa gives an odor signature to urine. Identification of the VOCs involved could lead to a potentially useful screening tool for PCa.

Similiar Findings...

ScienceDaily (Feb. 1, 2011) — Dogs can sniff out bowel cancer in breath and stool samples, with a very high degree of accuracy -- even in the early stages of the disease -- reveals research published online in the journal Gut.

The findings prompt the authors to suggest that chemical compounds for specific cancers circulate throughout the body, which opens up the prospect of developing tests to pick up the disease before it has had the chance to spread elsewhere.

A specially trained Labrador retriever completed 74 sniff tests, each comprising five breath (100 to 200 ml) or stool samples (50 ml) at a time, only one of which was cancerous, over a period of several months.

The samples came from 48 people with confirmed bowel cancer and 258 volunteers with no bowel cancer or who had had cancer in the past.

Around half of the volunteer samples came from people with bowel polyps, which although benign, are considered to be a precursor of bowel cancer. And 6% of the breath samples and one in 10 of the stool samples from this group came from those with other gut problems, such as inflammatory bowel disease, ulcers, diverticulitis, and appendicitis.

The bowel cancer samples came from patients with varying stages of disease, including early stage.

The dog successfully identified which samples were cancerous, and which were not, in 33 out of 36 breath tests and in 37 out of 38 stool tests, with the highest detection rates among those samples taken from people with early stage disease.

This equates to 95% accuracy, overall, for the breath test and 98% accuracy for the stool test, compared with conventional colonoscopy -- a procedure involving a tube with a camera on the end inserted through the back passage.

Samples from smokers or from those with other types of gut problems, which might be expected to mask or interfere with other smells, did not pose a problem for the dog.

This indicates that there are specific discernible odours given off by cancer cells which circulate around the body, say the authors. And it is backed up by other research and anecdotal evidence indicating that dogs can sniff out bladder, skin, lung, breast and ovarian cancers, they add.

The authors concede that using dogs to screen for cancers is likely to be impractical and expensive, but a sensor could be developed to detect the specific compounds.

The faecal occult blood test, which picks up hidden blood in a stool sample is an effective and non-invasive method of screening for bowel cancer, say the authors, but it is only able to pick up early stage disease in one in 10 cases.

"Early detection and early treatment are critical for the successful treatment of cancer and are excellent means for reducing both the economic burden and mortality [of bowel cancer]," comment the authors.