Using body odor to detect disease is not new. Patients with full-blown, uncontrolled diabetes produce a condition called ketoacidosis, in which their skin not only tastes sweet, but also gives off a strong, recognizable odor that smells like nail polish remover.
Someone with chronic kidney failure may have breath that has a fishy odor; and patients with bowel obstructions have breath that literally smells like feces.
Now doctors have taken the art of diagnosing disease from smell one step further by creating devices that analyze breath odor to detect certain types of cancer.
The first of these is a tester developed by Dr Peter Mazzone of The Cleveland Clinic in Ohio working in conjunction with ChemSensing of Champaign, Ill. This hand-held device, which is roughly about the size of a quarter, uses a “colorimetric sensor array” to detect early stage lung cancer. A colorimetric sensor array is composed of a number of thin, polymer films, each of which is coated with a different dye. The dyes change color as a result of the chemical interactions between molecules.
Patients with lung cancer have volatile organic compounds (VOCs)-- mainly alkanes and benzene derivatives-- in their breath. Because air passes through the lungs, the breath will pick up bits of these VOCs. When the lung cancer patient breathes into the testing device, the dye that is sensitive to VOCs automatically changes color. Since the dye will react to even the slightest presence of VOCs, this methodology has a 75 percent success rate.
Lung cancer isn’t the only form of the disease that can be detected through breath. Researchers at the University of Michigan are perfecting a device to test breath for the presence of metabolites associated with breast cancer.
Metabolites are the products of the body’s metabolism. They are directly involved in the growth, development, and reproduction of normal cells. The basic principle behind the breast cancer detection device is to separate normal metabolites from those that result from the presence of breast cancer.
The tester’s surface has been designed with tiny pockets that contain oil and water. The cancer-causing metabolites are attracted to the oil and water pockets. When a woman breathes into the device, any cancer-indicating metabolites are collected in the pockets. This causes the tester’s surface to fill up and become dense. When this happens, an electrical charge is applied and the metabolites are ejected so that multiple tests could be performed on them in the same device.
The goal is to create a tester that is a non-invasive and inexpensive over-the-counter method to screen for breast cancer.
Inanimate devices aren’t the only methodologies being tried in the detection of lung and breast cancer. Man’s best friend may now become men and women’s best way to detect for these two types of cancer in the early stages.
In a study headed by Michael McCulloch of the Pine Street Foundation in San Anselmo, Calif., and Tadeusz Jezierski of the Polish Academy of Sciences, Institute of Genetics and Animal Breeding, researchers tested to see if dogs can detect cancers by sniffing the exhaled breath of cancer patients. Five dogs were given three weeks training to learn to detect lung or breast cancer by sniffing the breath of cancer patients. They were trained that when they positively identified a cancer patient, they were to sit or lie down directly in front of the test station containing the patient’s sample. They were also trained to ignore the test stations that contained healthy breath samples.
After training was completed, the dogs were presented with tubes that contained breath samples from 55 patients with lung cancer, 31 with breast cancer, and a control sample of 83 healthy individuals. All the cancer patients had confirmed their diagnosis either through a mammogram, or CAT scan and had not received any chemotherapy. The study showed that the dogs were able to detect breast and lung cancer with an accuracy rate of between 88 and 97 percent. The test also indicated that the dogs could detect both early and late stages of the diseases.
All of these studies have one vital factor in common. They prove that analyzing human breath has the potential to provide a non-invasive and more cost-effective method of testing for cancer that is more accurate than current diagnostic techniques. Making cancer screening cheaper and more available means it will increase the incidences of early detection when the prognosis for recovery is good.