Identifying Women With Cervical Neoplasia
July 1, 1999 4 minutes read
Identifying Women With Cervical Neoplasia
Abstract & Commentary
Synopsis: Among women with ASCUS Pap smear reports, HPV testing is as accurate as repeat Pap smear for identifying women for referral for colposcopy.
Source: Manos MM, et al. JAMA 1999;281:1605-1610.
Following the introduction of the bethesda System (TBS) terminology for Pap smear reporting, the ASCUS group became and remains a category that confuses both clinicians and patients. Although most women with ASCUS reports do not have significant disease (HGSIL or invasive cancer), some women with such reports do harbor a neoplastic lesion that must be treated. Many clinicians repeat an ASCUS Pap smear within 4-6 months and refer for colposcopy those women who once again have an abnormal report. Other clinicians perform colposcopy on all women with ASCUS cytology.
This study was developed in an effort to determine whether HPV DNA testing could identify those women with HGSIL or greater lesions among women who had an initial ASCUS cytology report.
The study population included 46,000 who received their health care from the Kaiser Permanente program in northern California. Initially 995 women with ASCUS reports were identified, though slightly fewer women were used for various aspects of the study based on appropriate exclusions. During the study, all women had conventional cytology performed using a cervical broom. The broom was then rinsed in the cytologic preservation fluid that is used for ThinPrep cytology slides. A brush device was then used to collect another sample that was placed in a transport medium for HPV testing.
Of the 46,000 women who had Pap smears, 3.5% were reported as showing ASCUS changes. An attempt was made to contact all women who had ASCUS reports based on the conventional smear. These women were asked to report for colposcopy. At the time of the colposcopic evaluation, cytology and HPV specimens were again collected prior to the application of acetic acid. Colposcopy was performed with biopsy and ECC as indicated.
Appropriate blinding of the colposcopist and the histopathologist was performed. HPV testing was performed both on the ThinPrep preservative and on the HPV transport medium. Hybrid Capture II was used to detect "high risk" HPV. Sixty-one percent of women with ASCUS reports participated in the study. The median age of the study’s participants was 37 years. Approximately one-half of the ASCUS reports favored reactive changes, a quarter of the ASCUS reports favored neoplasia, and approximately one-quarter were unclassified.
Among women who had an ASCUS smear followed by colposcopy and biopsy, normal histology was found in 79%. Sixty-four cases of HGSIL and one invasive cancer were identified. Approximately half of the HGSIL and cancer cases originally had an ASCUS report that favored neoplasia. In the study, 39.5% of women with ASCUS reports had a high-risk HPV detected in the original sample, and 39.9% of the repeat Pap smears were abnormal. When a matched-pairs comparison between HPV testing and repeat Pap smear collection was performed, the results demonstrated that both techniques were equally effective in detecting HGSIL or cancer lesions.
Based on the results of this study, a similar number of women would be referred for colposcopy, regardless of whether HPV testing or a repeat abnormal smear were the indicator for colposcopic referral. Manos and colleagues suggest that, because HPV testing can be performed on the preservative used for ThinPrep cytology specimens, it is possible that HPV testing might be more efficient than a collection of repeat-cytology specimens.
COMMENT By Kenneth Noller, MD
HPV DNA testing has been available for clinical use for a number of years. However, there has never been a clear-cut indication for its use, and the test is costly.
The results of this study suggest there might be a roll for HPV DNA testing that might be cost effective, though cost-effectiveness was not addressed in this particular study. Because the triage suggested by Manos et al requires that both ThinPrep cytology (increased cost) be used as well as HPV DNA testing (increased cost), a cost-effectiveness study is certainly indicated.
My interpretation of the article is that HPV DNA testing could be used in the following stepwise manner:
1. Cytology would be collected using the ThinPrep technique.
2. The laboratory would prepare and read all cytology slides and would retain the preservative solution for all cases.
3. For all ASCUS reports, the preservative solution would be submitted for HPV DNA testing.
4. All women who had a high risk HPV identified would be referred for colposcopy.
Using the above triage system would result in a similar rate of HGSIL identification as repeat cytology. Repeat cytology requires the patient to make another physician appointment, travel to the office, and miss work. The additional visit and cytology specimen generate a charge (cost). Although the HPV triage system requires use of a more expensive initial cytology method (costs associated with storage and handling of all preservative solutions and the cost of HPV testing), the overall cost of this type of triage might be less than repeat cytology. However, at this time, it is not clear to me which of the above methods of handling ASCUS smears is more appropriate since they both result in a similar number of women identified who have HGSIL. If the two methods are equally cost effective, the HPV DNA testing triage would seem to be superior since it does not require a second visit to the clinician. If the clinician uses both HPV testing and repeats the cytology in a few months, the triage costs skyrocket. One system or the other should be adopted, not both.
Manos et al studied HPV DNA testing among women with ASCUS Pap smear reports. They found that:
a. HPV DNA testing was superior to repeat Pap smear testing.
b. HPV DNA testing was as good as repeat cytology testing.
c. Repeat cytology testing was superior to HPV testing.
d. All women with ASCUS smears should be referred for colposcopy.
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