Slashdot Mirror
A Breathalyzer For Cancer
Tiger4 writes "Cancer researchers in the UK have come up with a way to sniff for lung cancer on the breath. 'From the results, the researchers identified 42 "volatile organic compounds" (VOCs) present in the breath of 83% of cancer patients but fewer than 83% of healthy volunteers. Four of the most reliable were used to develop a nine-sensor array made from tiny gold particles coated with reactive chemicals sensitive to the compounds.' Other sources have picked up the story as well. Obviously, this would be a big breakthrough for rapid screening, and early detection significantly improves outcomes."
Confirmed:
It's 86 percent accuracy:
http://www.google.com/hostednews/afp/article/ALeqM5gD0oDWeDtMfAYl0C5bvx6Yyd78Yg
) Human Kind Vs Human Creation
) It'd be interesting to see how many humans would survive to serve us.
P.R. Alert: This Slashdot story is a public relations release. The misleading Slashdot summary says, "Other sources have picked up the story...". In reality, they are inserting press releases everywhere they can, and the kind of work being done is not new.
... believes that the breath test will provide a more convenient and rapid method for diagnosing serious diseases than blood or urine analysis, and will require minimal medical intervention."
It was proven long ago that dogs can smell chemicals associated with cancer. For example, see this 2006 article in National Geographic News, Dogs Smell Cancer in Patients' Breath, Study Shows. That's part of what started the present interest in making a machine to detect cancer.
This February 2007 article is more interesting: Compact lung-cancer breath test may be possible. Quote: "The test uses 36 chemical dots that react to telltale compounds in a person's breath. The dots change colour when exposed to compounds that signify the presence of lung cancer."
This February 2007 article gives more information about how it is done: US Scientists Prototype Breath Test For Lung Cancer
Even Oprah's magazine had article in June 2009 about dogs sniffing cancer and making machines to imitate dogs: Sniffing Out Cancer. Quote: "The researchers are collaborating with scientists at the University of Maine, who are trying to mimic the dogs' cancer-sniffing abilities with laboratory machines." Another quote: "So far, the Pine Street Foundation dogs have done 25,000 scent trials for ovarian cancer."
Slashdot: Not quite as current as Oprah? Old news for nerds who were playing video games and wouldn't know the difference?
Many researchers are doing similar work. For example, see the February 2008 article, The Cancer Breathalyzer. Quote: "Dr Yousef
Other researchers are studying the possibility of using blood tests to detect cancer. See the December 2007 article, Study points to possibility of blood test to detect lung cancer.
Here is a November 2005 research paper that surveys some of the issues of early detection of cancer: The Progress and Promise of Molecular Imaging Probes in Oncologic Drug Development.
That's not how it works. Assuming 83% is the accuracy for both positives and negatives, and given a group of 100 people, 10 of whom have lung cancer, we would expect on average:
2 patients with cancer will not be detected.
17 cancer-free patients will be told they may have cancer.
If our patients have no increased risk for cancer, then our group of 17 false-positives are suddenly scared into receiving further (possibly expensive) further testing. Our two patients whose cancer was not detected ignore futher testing until it is too late.
Basically, this technique is mostly useless for general screening. Of course, widespread screening generally is a bad idea, due to false positives, so the best bet is always to stick with those with higher risks only. I could see this method gaining use in developing nations where an expensive test is not possible, as the false-negative rate is still smaller than the current rate of undiagnosed cancer. However, dealing with the false-positives is still a bitch.
Write your representatives! Repeal the 2nd Law of Thermodynamics!
False!