Page 63 - Screening for Cervical Cancer: Systematic Evidence Review

Chapter III. Results

1. HPV specimen obtained or processed (or both) only for women with abnormal

cytologic diagnoses on Pap testing;

2. Performance of HPV for predicting presence of CIN evaluated by colposcopy

and/or histology as the reference standard;

3. HPV test and reference standard applied within an average of 3 months; and

4. A validation of negative HPV results, such that a complete 2x2 table relating the

HPV test findings to the reference standard can be completed.

Table 10 summarizes the study populations and severity of disease identified in

populations included in the studies relevant to HPV testing as a triage tool. Although the

majority of these studies required an abnormal Pap test for enrollment, we required only that the

HPV test and the colposcopy and/or histology, and not Pap testing, occur within an average of 3

months’ time. Two of these studies were conducted in countries in which initial ASCUS and/or

low grade cytologic findings are followed by repeat Pap testing. Colposcopy is only done if

repeat cytology suggests risk of a high grade lesion. 66,67 This approach lengthens the time

between the index Pap and the use of HPV testing and colposcopy. It also increases the

probability that women undergoing colposcopy will have a histologic lesion. As a result of such

cytology-based triage, the studies from Iceland and the Netherlands reflect a comparatively high

prevalence of high grade lesions. 66,67 This finding has implications for this report because the

prevalence of high grade lesions in these studies is higher than one would expect if HPV testing

were used as initial triage at the time of a first abnormal Pap test, and prevalence does influence

diagnostic test characteristics. These studies may not be as informative for US clinicians

because within our screening approach, HPV is most attractive as a triage tool for guiding

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