In the current method for performing Pap smears, a physician smears cells from the cervix onto a slide and sends the slide to a laboratory. At the laboratory, cytotechnologists, who are college graduates with a year or two of training and a license, study the slide under a microscope; cytopathologists, who are physicians, review those that appear to have abnormalities or are indecipherable.
Cytotechnologists may look at 80 or more slides a day with the goal to find cancerous and precancerous abnormalities that may lead to invasive cancer. Within each smear, the cytotechnologist must look at 50,000 to 300,000 cells. Since more than 90% of specimens are normal, and since within each slide most cells are normal, looking for potential trouble spots can be like looking for a needle in a haystack. To further complicate the task, the cells on the slide aren't usually neatly laid out. They may be covered by mucus, blood, and other components from the specimen that obscure visualization. Sometimes they clump together or overlap each other; very often the cancer cells are hidden in the mess.
Because this method is so dependent on human observation, the test is subjective and prone to error. Typically, the same pathologist comes up with the same diagnosis for the same sample only 80-90% of the time.
The Cytyc method for preparing the Pap smear eliminates some of the error in preparing the slide (i.e. blood, cell clumps, etc.), however the slides must still be reviewed by a cytotechnologist. Even though the Cytyc method gives a "cleaner" slide, the validity of the test is still subject to the tech's visual acuity.
The Matritech/Bayer collaboration for cervical cancer will significantly reduce or eliminate the dependence on the cytotech's ability through some type of automated screening using NMP technology.
Although I don't know the details of what the automation will involve, Bayer is the world's 4th largest diagnostics company and has a proven track record in developing automated test methods that are both sensitive and specific. I believe that they have the potential to blow away the Cytyc method, which is only a minor improvement on the status quo. |
