For Immediate Release

MARLBOROUGH, Mass., (Nov 16, 2004) - Cytyc Corporation announced today that eleven studies evaluating the performance of the ThinPrep(R) Imaging System were presented this week at the 52nd Annual Scientific Meeting of the American Society of Cytopathology (ASC) in Chicago. The studies reported on a range of implementation and performance criteria including validation protocols, disease detection and impact on workload.

Three of the studies presented were conducted at the Cleveland Clinical Foundation. A platform presentation by Dawn Underwood, C.T.(ASCP), entitled, "Implementation of the ThinPrep Imaging System: Impact on Cytology Laboratory Workload, Turnaround Time and Quality Parameters," reported a significant reduction in turnaround time after implementing Image-Directed Cytology(TM), which the author noted may improve physician and patient satisfaction. A second study presented by Andrea Dawson, M.D., "ThinPrep Imager System (TIS) Performance in the Diagnosis of Uncommon Malignancies," reported that cytotechnologists using the TIS correctly diagnosed these abnormal cells particularly in glandular lesions. The third study, "Quality Control Re-Screening in an Era of Computer-Assisted Imaging: What Can We Learn?," by Susan Porter, M.D., and others, evaluated abnormalities identified on quality control rescreening to assess location (machine) vs. interpretation errors.

Two studies were conducted by M. Nasar Queshi, M.D., Ph.D., and others at Lakewood Pathology Associates in Lakewood, New Jersey. "Impact of the ThinPrep Imaging System on Detection Rates of Cervical Abnormalities," showed a statistically significant increase in the detection of LSIL or higher (LSIL+) by cytotechnologists using the ThinPrep Imaging System compared to manual review. A second study, "Validation of the Accuracy of the ThinPrep Imaging System to Identify Abnormalities," concluded that cytotechnologists using the ThinPrep Imaging System correctly identified normal cases, allowing accurate identification of significant cellular abnormalities and organisms.

Fern S. Miller, M.S.M., C.T.(ASCP), and others at Metropolitan Pathologists in Denver, Colorado, completed two studies in which the ThinPrep Imaging System was compared to and validated against manual screening. "Comparison of Manual and Imaging-Directed Screening of the ThinPrep Pap Test in a Large Metropolitan Cytology Practice," reported a statistically significant increase in the rate of LSIL and HSIL detection by cytotechnologists using the ThinPrep Imaging System compared to manual screening. The validation study described the protocol when implementing the Imager at Metropolitan Pathologists Laboratory.

"The ThinPrep Imaging System in the Detection of High Grade Squamous Intraepithelial Lesions (HSIL) of the Uterine Cervix," a study conducted by Kathleen Richard, C.T.(ASCP), C.T.(IAC), of Mercy Medical Center in Springfield, Massachusetts, reported that "based on early evidence, it appears that Paps screened with the ThinPrep Imaging System detect a significantly higher number of HSIL than non-imaged manually screened ThinPrep Paps."

Jonathan Weintraub, M.D., of Laboratoire Weintraub in Geneva, Switzerland, presented a study on the comparison of the ThinPrep Imaging System and manual screening in the detection of abnormal cervicovaginal cytology specimens. Results indicate improvements in standardization and productivity with the Imager do not appear to have a negative impact on sensitivity.

Another study conducted in Europe, "Validation of the ThinPrep Imaging System: A Multi-Center European Study," presented data showing that cytotechnologists using the ThinPrep Imaging System are more effective than Manual review for the detection of ASCUS and more severe cervical abnormalities. The results are consistent with the U.S. based trial that led to FDA approval.

Finally, a study by Deanna Iverson, of Palo Alto Foundation, "Impact of the ThinPrep Imaging System on the Detection of Cervical Abnormalities," reported that detection rates for LSIL and more severe cases increased with cytotechnologist use of the ThinPrep Imaging System compared to manual screening.

"It is outstanding to see that in many instances the performance of the ThinPrep Imaging System in routine laboratories exceeds the results we saw in our multi-site clinical trial," said James Linder, M.D., senior vice president and chief medical officer of Cytyc Corporation. "We hope that laboratories that have implemented this state-of-the-art technology will continue to evaluate its performance and present their findings to the medical community."

The ThinPrep Imaging System is the first fully integrated, interactive computer system that assists cytotechnologists and pathologists in the primary screening and diagnosis of ThinPrep Pap Test slides. The ThinPrep Imaging System combines revolutionary imaging technology with human interpretive expertise to improve cervical cancer screening efficiency and performance. The U.S. Food and Drug Administration approval of the ThinPrep Imaging System was based on clinical trial results that demonstrated an improvement in sensitivity for the detection of ASCUS+, an improvement in specificity for the detection of HSIL+ and a workload limit of 200 ThinPrep Imaging System assisted slides in no less than an 8-hour workday.