Abstract
Background : Major screening abnormalities in pre-colposcopic
stage are tests results that imply direct referral to colposcopy (and/or
expedited treatment) without performing additional high-grade squamous
intraepithelial lesions or worse (HSIL+) risk selection testing.
Currently, both clinically validated HSIL+ risk selection tests, reflex
cytology and reflex p16/Ki67 dual staining (DS), are being compared for
use in primary HPV-based screening to avoid possible overtreatment, but
there is still no sufficient data available for their performance.
Methods : Among 30,066 liquid-based cervical cancer screening
tests results, a group of 332 women was selected with available HRHPV
tests results with 16/18 limited genotyping, liquid-based cytology, DS,
and histology results from standardized colposcopy with biopsy. In HPV
16/18+ cases, three triage approaches were retrospectively analyzed.
Predictive values for detection of HSIL+ were calculated and number of
colposcopies required in each strategy.
Results : Both triage models with DS used (reflex cytology
followed by DS, and reflex DS alone in all cases) had significantly
higher PPV for HSIL+ than strategy with reflex cytology alone
(44.2%/45.7% vs. 28.3%; p<0.0001). In models with DS, less
colposcopies were required (95/92 vs. 152) and less colposcopies were
needed per HSIL+ detection (2,26/2,19 vs. 3,54). Only 1 HSIL+ case was
missed in both triage models with DS incorporation.
Conclusions : p16/Ki67 dual-stain may be an effective, alone or
combined with cytology, triage test to detect HSIL+ in patients with
major screening abnormalities in primary HPV-based cervical cancer
screening. Performing cytology as the first triage test improves the
strategy by enabling referrals to expedited treatment in selected cases.
KEY WORDS: cervical cancer screening; CIN; high-risk HPV; HPV
16 and 18; p16/Ki67 dual staining; triage
Introduction
Cervical cancer still remains a significant global public health burden,
particularly in low- and middle-income countries where access to regular
screening and preventive interventions is limited [1]. The
implementation of cervical cancer screening programs has substantially
reduced the incidence and mortality rates of this malignancy in many
high-income countries [2]. The emergence of 13-14 high-risk types of
human papillomavirus (HRHPV) (family Papillomaviridae , subfamilyFirstpapillomavirinae , genus Alphapapillomavirus , speciesAlphapapillomavirus 9) [3] as a primary etiological agent in
the development of cervical cancer has led to revolutionary changes in
screening strategies [4-6]. HRHPV testing, with its very high
sensitivity, has gained prominence as a cornerstone in early detection
efforts [7-9].
In recent years, advancements in genotyping techniques have further
refined our understanding of HPV’s role in cervical carcinogenesis
[10]. The limited genotyping has opened possibilities to
differentiate between HPV genotypes with varying carcinogenic
propensities. Incorporating this information into clinical
decision-making could enable a targeted approach to colposcopy referral,
risk stratification and minimizing unnecessary interventions for
individuals at lower risk [11]. Primary HPV-based screening with
genotyping, presents a promising approach to enhance the accuracy of
cervical cancer secondary prevention, specifically in triaging
individuals at highest risk for colposcopy referral [12]. But
performing a colposcopy in all major screening abnormalities, with
potentially higher risk of histologic high-grade intraepithelial lesions
with a quantification of cervical intraepithelial neoplasia in grade 2
or worse (HSIL/CIN2+) implying a direct referral to colposcopy without
prior triage testing, identified through primary HPV-based screening
with limited genotyping, raises important clinical and resource-related
considerations [13]. The cost associated with performing
colposcopies in all individuals with major screening abnormalities can
strain healthcare systems and lead to resource allocation challenges.
Furthermore, it may lead to overtreatment, causing unnecessary stress
and discomfort for patients.
The
transition to primary HPV-based screening with a limited genotyping new
paradigm needs a critical evaluation of the clinical algorithm guiding
follow-up steps. HPV 16 and/or 18 positive results (HPV 16/18+) have the
highest HSIL/CIN2+ risk among all HRHPV-positive results [14-16].
Currently some of recommendations worldwide, including the 2019 American
Society for Colposcopy and Cervical Pathology (ASCCP 2019) Consensus
Guidelines, are advising colposcopy for all HPV 16/18+ results without
any triage test [14-16]. In the ASCCP 2019 Guidelines, cytology as a
triage test for all results is highly valued due to its importance in
referring patients to expedited treatment, defined as excisional
treatment, without preceding confirmatory colposcopy with biopsy), and
not only to colposcopy. It is also recommended that all cases with HPV
16/18+ ASC-H and HPV 18+ HSIL results should be referred to colposcopy
or expedited treatment and HPV 16+ HSIL patients directly to expedited
treatment [14,15]. The second examined triage test approved (e.g. by
the U.S. Food and Drug Administration or the Polish Society of
Colposcopy and Cervical Pathology) in selected HPV-positive cases and in
patients with abnormal cotesting results, is p16/Ki67 dual-staining
(DS), which is characterized by high sensitivity and specificity for
HSIL/CIN2+ detection [17-23].
The landscape of cervical cancer secondary prevention is evolving
rapidly, driven by advances in HRHPV testing and genotyping
technologies. While the use of colposcopy for all major screening
abnormalities detected through primary HPV-based screening with limited
genotyping is the most common management recommended in available
guidelines, it is imperative to critically assess the evidence
supporting this approach for all HPV 16/18+ cases. By evaluating the
potential benefits and limitations demonstrated in different strategy
ramifications, we aim to provide a comprehensive perspective on the need
of colposcopy referral in these patients. The positive predictive value
(PPV) is a valuable determinant of the accuracy of the diagnostic tests.
It depends on the prevalence of the condition in the screened population
and both the sensitivity and the specificity of the test [24]. PPV
determines the probability that a positive test result correctly
predicts the presence of the disease, so it is more important for
clinicians than sensitivity and specificity [25].
This retrospective study is to evaluate performance characteristics of
three different triage models, incorporating cytology alone or DS alone
or in combination, in HPV 16/18 positive patients who had undergone
primary HPV-based cervical cancer screening, for detecting HSIL/CIN2+
cases.
Materials and methods
Study population
The study is a post-hoc analysis including a total of 30,066 cervical
cancer liquid-based screening (LBS) tests results. This dataset
comprises 20,605 results from liquid-based cytology (LBC), 8331 results
from HRHPV with limited HPV 16/18 genotyping, and 1130 results from DS.
These LBS tests were derived from a diverse cohort of women ranging from
15 to 92 years old, with a mean age of 40.9. Data for analysis were
extracted from LBS test results obtained between August 2015 and July
2020. These tests were sourced from opportunistic cervical cancer
screening programs conducted at the Corfamed Woman’s Health Center, one
of the largest private outpatient gynecological clinics located in an
urban area of Lower Silesia, Poland. The cervical cancer screening at
the Center employed three distinct models during the study period:
primary cytology with reflex HRHPV, primary cotesting, and primary
cotesting plus (simultaneous cotesting and DS). The reflex HRHPV test
was recommended for cases with minor cytological abnormalities (ASC-US
or LSIL) in the primary cytology screening. DS was conducted for ASC-US
or LSIL cases in both cytology- and cotesting-based models, as well as
for all positive HRHPV test results. The final study cohort consisted of
332 patients aged over 25 years, all of whom had undergone LBS testing
and subsequent colposcopy with biopsy at the Center (Figure 1). This
selected group of patients had no prior HPV status available. A
retrospective analysis of
cytologic-virologic-immunocytochemical-histologic test results was
conducted, and the PPV of cytology and DS as triage tests for specific
major cervical cancer screening abnormalities was evaluated. The study
data were retrieved from the Center’s registry, with a detailed
methodology previously described in a series of related studies
[26-29]. The study received ethics committee approval (ID:
118.6120.36.2023).