Recent major developments in cervical cancer screening including the growing popularity of the ThinPrep pap smear technique and testing for Human Papilloma Virus (HPV) continue to engender significant discussion in our local provider community. In response to numerous questions and concerns surrounding these issues the Departments of Pathology and Obstetrics and Gynecology at Maine Medical Center convened a small group under the leadership of Michael Jones, MD, Spectrum Medical Group, and Chip Wiper, MD, to bring forth general recommendations for the use of these tests.

ThinPrep Cytology

Large, multi-center trials and numerous other studies have shown that the use of ThinPrep pap smears significantly increases cytologic sensitivity in the detection of low and high grade squamous and glandular cervical cancer precursors. While much of the enhanced sensitivity was historically detected in low-grade lesions, recent literature conclusively shows that there are significantly increased detection rates in the high-grade group as well. In addition, these data now appear to include both high and low risk patient groups. Other benefits include the lowering of ASCUS and unsatisfactory rates. In response, many parts of the country (particularly New England) have experienced substantial conversion of their conventional Pap smear population to ThinPrep. This technology now represents greater than 50% of Paps nationwide and over 70% in Massachusetts. NorDx Laboratory is experiencing a significant rise in conversion to ThinPrep (now approximately 30-35%). All major Maine payors now reimburse at rates that cover the majority of the increased cost over conventional Paps. We recommend that all providers strongly consider converting to this technique for all of their patients. NorDx Laboratory currently offers the ThinPrep Pap test. Supplies and/or further information regarding ThinPrep can be directed to NorDx client support at 885-7830 or Dr. Michael Jones, (207) 871-2959.

Human Papilloma Virus (HPV) Testing

While HPV testing is not, and likely will not, be advocated for use as a “screening test” in the United States considerable study has been directed towards the use of HPV testing as a secondary step in the triage of the “minimally abnormal pap smear” (e.g. ASCUS). Data from both Kaiser Permanente and The NCI – sponsored Ascus low-grade triage study have suggested that triaging the ASCUS patient to immediate colposcopy (if high risk virus positive) or 4-6 month follow-up pap smear (if low risk or no HPV) is a more cost effective way to manage the ASCUS patient that maximizes the detection of high grade cervical cancer precursors. In this setting, HPV typing is ordered as a reflex test taken from the ThinPrep vial immediately after the diagnosis of ASCUS has been rendered. Preliminary studies have suggested that this may have a favorable cost benefit status in the overall management of the patient. Use of the HPV algorithm is most economically and conveniently accomplished with use of the ThinPrep pap technique, otherwise a separate collection will be necessary.

It is important to emphasize that HPV testing is indicated only in the setting of the ASCUS patient or in rare circumstances when requested by the pathologist to resolve difficult pap/colposcopy discrepancies. It is not helpful in managing the patient with low grade, high grade, or negative results. The meaning of high risk virus positivity in the face of negative smears is unknown and may lead to unnecessary worry on the part of the clinician and/or patient. HPV testing is available through NorDx Laboratory. If requested, a ThinPrep pap test should be performed and a request for “HPV testing if ASCUS” written on the requisition form. Any questions regarding HPV testing, including test result interpretation, should be directed to Drs. Michael Jones or Chip Wiper.

Michael A. Jones, MD, Chief, Department of Pathology, Maine Medical Center

Donald Wiper, MD, Co-Director, Gynecologic Oncology, Maine Medical Center