p16/Ki-67 dual-stained cytology for detecting cervical (pre)cancer in a HPV-positive gynecologic outpatient population

Abstract

Women who test positive for a high-risk type of the human papillomavirus (HPV) require triage testing to identify those women with cervical intraepithelial neoplasia grade 3 or cancer (≥ CIN3). Although Pap cytology is considered an attractive triage test, its applicability is hampered by its subjective nature. This study prospectively compared the clinical performance of p16/Ki-67 dual-stained cytology to that of Pap cytology, with or without HPV16/18 genotyping, in high-risk HPV-positive women visiting gynecologic outpatient clinics (n = 446 and age 18-66 years). From all women, cervical scrapes (for Pap cytology, HPV16/18 genotyping, and p16/Ki-67 dual-stained cytology) and colposcopy-directed biopsies were obtained. The sensitivity of p16/Ki-67 dual-stained cytology for ≥ CIN3 (93.8%) did neither differ significantly from that of Pap cytology (87.7%; ratio 1.07 and 95% confidence interval (CI): 0.97-1.18) nor from that of Pap cytology combined with HPV16/18 genotyping (95.1%; ratio 0.99 and 95% CI: 0.91-1.07). However, the specificity of p16/Ki-67 dual-stained cytology for ≥ CIN3 (51.2%) was significantly higher than that of Pap cytology (44.9%; ratio 1.14 and 95% CI: 1.01-1.29) and Pap cytology combined with HPV16/18 genotyping (25.8%; ratio 1.99 and 95% CI: 1.68-2.35). After exclusion of women who had been referred because of abnormal Pap cytology, the specificity of p16/Ki-67 dual-stained cytology for ≥ CIN3 (56.7%) remained the same, whereas that of Pap cytology (60.3%) increased substantially, resulting in a similar specificity of both assays (ratio 0.94 and 95% CI: 0.83-1.07) in this sub-cohort. In summary, p16/Ki-67 dual-stained cytology has a good clinical performance and is an interesting objective microscopybased triage tool for high-risk HPV-positive women. Persistent infection with a high-risk type of the human papillomavirus (HPV) is essential for the development of almost all cervical cancers. 1,2 Testing for high-risk HPV has been shown to provide superior protection against cervical intraepithelial neoplasia grade 3 and cervical cancer (together referred to as ≥ CIN3) compared with cervical cytology (Pap cytology). 3 However, most women who test positive for high-risk HPV clear the virus spontaneously and do not develop clinically relevant cervical disease. Therefore, additional triage testing is required to identify the subgroup of high-risk HPVpositive women who actually have ≥ CIN3, thereby Correspondence: Professor CJLM Meijer, MD PhD,

Management of high-risk HPV-positive women for detection of cervical (pre)cancer

“…In these studies, p16/Ki-67 dual-stained cytology had a consistently high sensitivity for ≥CIN3 (86.9-93.8% which was comparable to that of Pap cytology [65][66][67]. The specificity for ≥CIN3 of p16/Ki-67 dual-stained cytology was estimated at 51.2% [67] to 56.9% [65], which is high compared to Pap cytology (44.9% [67] to 48.7% [65]). Because p16/Ki-67 dualstained cytology can be adequately interpreted by relatively untrained staff, it has a decreased interobserver variability compared to Pap cytology [68,69].…”

“…Although data on the long-term ≥CIN3 risk in p16/Ki-67 dual-stain negative women are currently lacking, results from the studies with short-term follow-up (up to 2 years) [65] are promising, reporting NPVs of a single p16/Ki-67 dual-stained cytology test between 97.4% and 99.4% [65,67]. In a population-based screening cohort, Wentzensen et al found a PPV of 12.4% [65], whereas in an outpatient population Luttmer et al found a PPV of 29.9% [67].…”

“…The combination of Pap cytology and methylation analysis, which have been suggested to serve as complementary markers in terms of detection of early and advanced CIN [32], could serve as a sensitive strategy that, in contrast to Pap cytology alone, detects all carcinomas and virtually all CIN3. Table 5 provides an overview of test characteristics (that is, sensitivity, specificity, NPV, PPV) of Pap cytology, HPV16/18 genotyping, p16/Ki-67 dual-stained cytology, and methylation analysis in a single (outpatient) study population [51,67,100,114]. A general limitation of microscopy-based strategies is the fact that these can only be adequately performed on cervical scrapes collected by health-care professionals.…”

“…The simultaneous expression of p16 and Ki-67 in one cell is indicative for cell cycle dysregulation and appears indicative for a transforming hrHPV infection [61][62][63][64]. Three recent studies have addressed the performance of p16/Ki-67 dualstained cytology for triage of hrHPV-positive women, in population-based screening cohorts (n = 1509 [65] and n = 396 [66]) and a gynecologic outpatient population (n = 446 [67]). In these studies, p16/Ki-67 dual-stained cytology had a consistently high sensitivity for ≥CIN3 (86.9-93.8% which was comparable to that of Pap cytology [65][66][67].…”

“…Three recent studies have addressed the performance of p16/Ki-67 dualstained cytology for triage of hrHPV-positive women, in population-based screening cohorts (n = 1509 [65] and n = 396 [66]) and a gynecologic outpatient population (n = 446 [67]). In these studies, p16/Ki-67 dual-stained cytology had a consistently high sensitivity for ≥CIN3 (86.9-93.8% which was comparable to that of Pap cytology [65][66][67]. The specificity for ≥CIN3 of p16/Ki-67 dual-stained cytology was estimated at 51.2% [67] to 56.9% [65], which is high compared to Pap cytology (44.9% [67] to 48.7% [65]).…”