Not only do cancer cells grow and spread differently than normal cells, many of them also digest chemicals differently.
We’re learning that small amounts of these chemicals (such as benzene and formaldehyde) can be detected in the breath of cancer patients. And that just might give us a new, easier way to detect cancer in the first place.
A report from the British Journal of Surgery describes early success with just such a specialized \”breathalyzer\”. In a small group of patients (some of whom had colon cancer) the breath test could identify the cancer patients 76% of the time. And earlier this year, an Israeli study of 74 patients tested whether a breath test could tell malignant lung tumors from benign ones (the breath test was correct 90% of the time).
These early results are promising, but there’s a lot more work to be done before any of this is ready for clinical use. To be really useful, a screening test must detect a cancer before it’s had a chance to spread. A test that can only identify cancer in the later, incurable stages isn’t going to do anyone much good. We’ll need a lot more patients to participate in good clinical trials if this is going to go anywhere.
But I’ll admit to being optimistic. I keep remembering all the stories patients have told me about dogs or cats closely sniffing a body part affected by cancer, as though their pets could smell something different. And one of my mentors used to say \”if a shark can detect a drop of blood in several gallons of ocean water, we should be able to identify tumors by smell\”. Maybe he was right all along.
Breath testing in lung cancer:
http://www.medpagetoday.com/MeetingCoverage/AACR-IASLC/30582
http://www.technologyreview.com/news/426894/cancer-breath-test-enters-clinical-trials/
Breath testing in colon cancer:
http://www.huffingtonpost.com/2012/12/06/colorectal-cancer-breath-test_n_2246218.html
http://onlinelibrary.wiley.com/doi/10.1002/bjs.8942/abstract
Clinical trials:
http://clinicaltrials.gov/ct2/show/NCT01386203
http://clinicaltrials.gov/ct2/show/NCT01700647?term=breath+test&rank=11
