Cervical Cancer Detection at Yale Pathology Cytoprep Laboratory
Since the introduction of the Pap smear test for the early detection
of cervical cancer in 1941 there has been a 70% reduction in the cervical
cancer mortality rate, the most significant reduction of mortality attributable
to any modern medical test. The latest developments in cervical cancer
detection technology promise to reduce this rate even further.
While instrumental in reducing mortality rates, the conventional Pap
smear test does have limitations, including the occasional obscuration
of cells on the slide by blood and/or inflammation and the deterioration
of the cells through air-drying after the sample is smeared on a slide.
Another problem is the routine discarding of a high percentage of cells
that are thrown away in the doctor's office on the sampling device.
Liquid-based Pap test technologies are designed to overcome these limitations
by placing the cervical sample immediately in a fixative vial, eliminating
air-drying, and allowing for the transfer of a higher percentage of
cells to the specimen container.
In the ThinPrep® Pap test, the first liquid based technology available,
the cells are presented as a monolayer in a 20mm diameter circle that
can be viewed by the cytopathologist with little in the way of obscuring
blood and inflammation, offering a greater sensitivity in the detection
of abnormality. In the alternative liquid-based Pap test, the SurePath
Pap test, gynecologic samples are collected with a brush that remains
in the specimen vial; this virtually assures 100% transfer of the patient's
sample to the cytology laboratory. The increased sensitivity of either
liquid-based test ensures that more slides are satisfactory for evaluation
and reduces the number of unnecessary patient callbacks for repeat testing.
Another new technology, the FDA-approved FocalPoint Primary Screening
System, has also been adopted at Yale as a means of improving accuracy
in the laboratory. This is a computerized instrument that screens Pap
smear slides through high-speed, high-resolution video microscopy. The
system ranks slides according to the likelihood of abnormality, allowing
up to 25% of Pap smears deemed normal to be "archived" without
human review. The collective wisdom of leading pathologists has been
programmed into screening algorithms to accurately identify abnormal
cells. Clinical trials show that the FocalPoint system improves a laboratory's
ability to detect abnormal cervical cells, while also effectively assessing
specimen adequacy.
How do I prepare for the test?
Tell your health care provider (1) if you've had a prior abnormal
Pap smear; (2) if you might be pregnant; and (3) if you are taking any
medications, including birth control pills. Avoid douching, using tampons,
having intercourse, and tub bathing 24 hours before the test. Empty
your bladder just before the test.
What do the results mean?
Results are reported using the Bethesda Classification System:
• Negative for Intraepithelial Lesion or malignancy
• Atypical Squamous Cells of Undetermined Significance or ASCUS (abnormal
findings, which may be related to a benign or a precancerous
condition; follow-up recommended)
• Low Grade Squamous Intraepithelial Lesion (precancerous condition)
• High Grade Squamous Intraepithelial Lesion (precancerous condition)
• Carcinoma (malignant lesion)
When should Pap testing begin and how long should it continue?
Screening should begin when a woman becomes sexually active, requests
contraception, or reaches the age of 18. Routine Pap tests should then
be performed annually, as long as the previous Pap test was normal.
Pap test screening should continue through the age of 65, and then may
be reduced to once every 3 years as long as there are 2 consecutive
Pap tests that were normal, and no other pre-existing risk factors or
medical conditions are present.
