The probability for a Pap test to be abnormal is directly proportional to HPV viral load: results from a Swiss study comparing HPV testing and liquid-based cytology to detect cervical cancer precursors in 13,842 women.
In a study involving 13,842 women and 113 gynaecologists, liquid-based cytology and HPV testing for detecting cervical cancer were compared. A total of 1334 women were found to be positive for one or both tests and were invited for colposcopy with biopsy. A total of 1031 satisfactory biopsies on 1031 women were thereafter collected using a systematic biopsy protocol, which was random in the colposcopically normal-appearing cervix or directed in the abnormal one. In all, 502 women with negative tests were also biopsied. A total of 82 histologic high-grade squamous intraepithelial lesion (HSIL) were reported in biopsies, all from the group with one or both tests positive. Sensitivity and specificity to detect histologic HSIL were 59 and 97% for cytology, and 97 and 92% for HPV. In total, 14% of reviewed negative cytological preparations associated with histologic HSIL contained no morphologically abnormal cells despite a positive HPV test. This suggested a theoretical limit for cytology sensitivity. HPV viral load analysis of the 1143 HPV-positive samples showed a direct relationship between abnormal Pap test frequency and HPV viral load. Thus, not only does the HPV testing have a greater sensitivity than cytology but the probability of the latter being positive can also be defined as a function of the associated HPV viral load.
Bigras
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Laboratoire Cytopath, Unilabs SA, 12 Place Cornavin, Genève 1, CH-1211, Switzerland. gilbert_bigras@yahoo.com
de Marval
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D000293:Adolescent; D000328:Adult; D000368:Aged; D001706:Biopsy; D003127:Colposcopy; D004279:DNA, Viral / Q000032:analysis; D005260:Female; D006801:Humans; D008875:Middle Aged; D027383:Papillomaviridae / Q000235:genetics / Q000302:isolation & purification*; D030361:Papillomavirus Infections / Q000175:diagnosis / Q000821:virology*; D016133:Polymerase Chain Reaction; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D013557:Switzerland; D002583:Uterine Cervical Neoplasms / Q000175:diagnosis / Q000821:virology*; D014626:Vaginal Smears / Q000379:methods*; D019562:Viral Load; D002578:Uterine Cervical Dysplasia / Q000175:diagnosis / Q000821:virology*
D004279:DNA, Viral