The Scent of Cancer Could Lead to Early Detection

Imagine being able to detect cancer through smell. It is certainly within the realm of possibility. The human skin releases chemicals known as volatile organic compounds (VOCs) in differing amounts, which in turn generates unique scents. And while our noses are unable to detect them, a canine's sensitive nose can. Dogs have been trained to "sniff out" tumors and to detect changes in the odor of urine, which could indicate bladder cancer. Researchers now hope to use this premise to develop a noninvasive test to diagnose skin cancer.

In a study, researchers at the Model Chemical Senses Center in Philadelphia tested the air above tumor sites in 11 patients with basal cell carcinoma, as well as the healthy skin of 11 volunteers. While the same chemicals were present in both groups, the skin cancer sites had different concentrations. "We found that the odor profile coming from the skin of cancer patients was markedly different than that coming from healthy skin," said study author Michelle Gallagher, Ph.D. "Researchers have speculated that tumors give off different odors, but we're the first to identify and quantify the compounds involved in skin cancer odors."

So far, the team has developed an "odor profile" only for basal cell carcinoma, but they are working on profiles for the more serious squamous cell cancer and for melanoma, the deadliest form. They envision linking the profiles to a nanosensor-an electronic nose-that could be moved across the skin, giving off an alarm when a cancerous pattern is detected. Dr. Gallagher says even though their work is preliminary, "within a few years, it's reasonable to say that this could end up being a diagnostic tool that would be a routine thing one could do in a doctor's office. It's a real possibility."

However, other experts are less optimistic. Dr. Jean-Claude Bystryn, former head of the melanoma program and vaccine clinic at New York University Medical Center told the Washington Post that "it's hard to imagine" this replacing the standard method of diagnosing cancer, which is basically to look at a specimen under the microscope. "Because when you're dealing with cancer, the margin for error is really small. You don't want to miss something that may be a cancer that then doesn't get treated. And you don't want to treat someone for cancer if they actually have something else. So, it's really a very novel and interesting idea but one which I think really needs to be further researched and carefully confirmed," he said.

Odor profiling is also being tested for other cancers and conditions. Researchers have developed an "electronic nose" that may one day be used to diagnose asthma and a breath sensor that reportedly detects 75 percent of lung cancer cases. Another novel device, called the Sniff Magnitude Test (SMT), has the potential to detect early warning signs of Alzheimer's, Parkinson's and other neurological diseases.