Cervical Cancer: Improving Detection Through the Use of Computers

The Pap test, developed by George Papanicolaou, M.D., Ph.D., in the 1940s, has become a routine part of gynecological exams resulting in a dramatic drop in the number of women dying from cervical cancer. However, problems of errors remain. Cytotechnologists have the challenge of finding as few as a dozen abnormal cells on a laboratory slide lined with between 50,000 to 300,000 cervical cells! To compound the problem, abnormalities in cell shape may be slight and difficult for even the trained eye to detect. In addition, infection may mask the cancerous cells.

Computerized Systems Improve Detection
The FDA has approved the ThinPrep Processor Model 2000 for automatically preparing slides making it easier for screening atypical cells. The ThinPrep system is especially effective for detecting low-grade squamous intraepithelial lesions (SILs) and some of the more severe lesions. The ThinPrep system concentrates the cellular material and filters out a lot of blood and other materials. This provides for better detection of cancer cells by the cytotechnologist.

Other new systems available to health professionals are used for screening the slides for abnormal-looking cells. One system, PAPNET, uses neural net computer technology. Its technology was originally designed to detect flying missiles. The system essentially learns by example. It is fed a series of digitized images of Pap slides, and from these slides, the computer develops guidelines for identifying abnormal cells. Once cells are identified by the system as "abnormal", an enlarged color image of the cells is generated for the cytotechnologist for review.

One other Pap test re-screening system is the AutoPap 300 QC. This computerized system uses image interproduction and pattern recognition techniques for classifying cells as abnormal. Once the cytotechnologist performs a routine screening of the slides, the AutoPap 300 QC is used to re-screen the slides. The AutoPap 300 QC then scans the cells for hundreds of features, such as size, shape, density, and texture. Using sophisticated statistical screenings, it selects 10 to 20 percent of slides with the highest probability of having abnormal cells. These slides are then re-screened manually by the cytotechnologist.

Although these methods of detection are very effective in detecting abnormal cells, they are not foolproof. Also, there are a small percentage of women who develop a rare form of aggressive cervical cancer that can develop to advanced stages in under a year.

If you have been diagnosed with human papillomaviruses (HPVs), you could be at a greater risk for developing cervical cancer. Smoking also elevates the risks.

What can you do? Talk to your doctor about the testing methods used for your Pap test. Get regular gynecological checkups, as frequent as once per year. Do not douche or use vaginal spermicides or medicines within two days of your Pap test. Use barrier methods of contraception, such as a diaphragm with spermicide and condoms, and quit smoking!

Currently, the most effective way of preventing cervical cancer is early detection.