Long term results of follow-up after HPV self-sampling with devices Qvintip and HerSwab in women non-attending cervical screening programme

Since the introduction of the cervical cancer screening based on cell samples for cervical cytology (Pap smear) the incidence and mortality of cervical cancer has decreased dramatically.1, 2 In Slovenia, the highest peak of the cervical cancer incidence was registered in 1962 when age-standardised incidence rate (world) was 27.5/100,000. Due to the opportunistic screening the incidence was decreasing till the end of the eighties and a second peak was observed in 1997.3 Organised cervical screening national program ZORA (NP ZORA) was implemented in 2003 with conventional cytology at a three-years interval in women aged 20-64. A three-year coverage of the target population with a screening test is just above 70%.4 The lowest incidence of cervical cancer in Slovenia was registered in 2017 when 85 new cases were diagnosed and the age-standardised incidence rate (world) was 4.9/100,000.5

Despite good results of NP ZORA, there are still subgroups of women who do not attend for screening. In Slovenia, the coverage of the target population with screening test is decreasing with women’s age. It is below the targeted 70% in women 50 years or more. The lowest rate is in women aged 60-64 years with only 57%.4

In countries with organised screening programmes, the majority of new cases are diagnosed in women who were never screened or are under-screened. These women are often diagnosed at advanced stages. Nonattendance for screening is one of the most important risk factors for developing cervical cancer. Studies exploring screening non-attendance suggest a wide range of barriers, including fear of pain, embarrassment, shame, low perceived risk, absence of symptoms, lack of physicians, inconvenient clinic hours, forgetting an appointment, cultural barriers, low socioeconomic status, indirect costs, and worry about the result.6, 7

The discovery that human papillomaviruses (HPV) are aetiologically linked with cervical cancer has led to efforts to apply this knowledge to improve cervical cancer screening. Over the last two decades, HPV testing has become a part of clinical guidelines for cervical cancer screening, triage and follow-up after treatment in several countries.8

One of the advantages of HPV testing is the possibility for women to perform self-sampling. Systematic reviews and meta-analysis published in recent years have shown that self-sampling for HPV testing may increase a population uptake of cervical cancer screening, especially when HPV self-sampling kits were mailed directly to women.9, 10 HPV self-sampling is a process where a woman uses a kit to collect a vaginal sample, which is then sent for analysis by a laboratory, while sample taken by gynaecologist is obtained from the cervix. The difference between both methods has raised concerns about whether vaginal self-sampling is comparable to cervical clinician-sampling in detecting HPV. In the updated meta-analysis by Arbyn et al. in 2018, HPV assays based on polymerase chain reaction were as sensitive on self-samples as on clinical samples; however, the specificity to exclude cervical intraepithelial neoplasia grade 2 or more (CIN 2+) was 2% or 4% lower on self-samples than on clinical samples.11 HPV assays based on signal amplification were less sensitive on self-samples.11

For the first time, we are presenting the results of the Slovenian HPV self-sampling pilot study in colposcopy population that was conducted one year prior the large-scale randomised trial of HPV self-sampling.12 One and four-year sensitivity, specificity, positive, and negative predictive values for CIN2+, test agreement and CIN 2+ detection rates in women enrolled in the study were analysed. Results are stratified by the sampling modality (self, clinician), test (cytology, HPV), and self-sampling device (Qvintip, HerSwab).

Women were consecutively enrolled in the study at the colposcopy clinic at the University Medical Centre Maribor and General Hospital Celje during 2014–2016 and followed by the central National Cervical Cancer Screening Registry until the end of 2019. Women with pathologic Pap test, age 20–64 years, referred for a colposcopy according to National guidelines for the management of women with pathological cervical results13, were invited to participate in prospective observational study and all included women signed informed consent. Exclusion criteria were acute kolpitis or cervicitis and pregnancy. All women performed a self-collected vaginal swab for HPV testing at the clinic prior to the gynaecological examination. After self-sampling, the gynaecologist collected two cervical smears, first for conventional cytology and second for a HPV test. After that, all women underwent colposcopy and in case of abnormal colposcopy cervical biopsy was performed. Women were managed according to the colposcopy and biopsy results and the National guidelines for the management of women with pathological cervical results.13 There were two self-sampling devices used in the study: Qvintip (Aprovix AB, Uppsala Sweden) and HerSwab (Eve Medical, Toronto, Canada); however, each woman used only one self-sampling device. Hybrid Capture 2 (HC2, Qiagen, Hilden, Germany) assay was used for all HPV testing. Cytological and histological evaluations were performed by certified pathologists in laboratories as part of a regular Cervical Cancer Screening Programme. In the event of having more than one histopathological result, the pathological change of the highest grade was included in the analysis. Each cytology slide was evaluated twice: at the institution performing gynaecological examination and at Institute of Oncology Ljubljana.

This is the first time we are presenting the results of the Slovenian HPV self-sampling pilot study in the colposcopy population within the organised, population-based Slovenian cervical cancer screening programme ZORA. Four-year longitudinal accuracy and cumulative incidence of CIN2+ for HPV testing with samples taken by Qvintip and HerSwab self-sampling devices were analysed and compared to cytology and HPV tests with clinician-taken samples. The prevalence of HPV positive self-sampling results in our group of patients was 67.0%. In colposocpy studies among women with abnormal cervical smears, the reported prevalence of self-collected HPV positive tests ranges between 30 and 77%.15, 16, 17, 18, 19, 20, 21 We found more positive HPV tests in the Qvintip group compared to the HerSwab group (70.3% vs 63.3%) probably due to a lower age of women and higher prevalence of CIN2+ in the Qvintip group compared to the HerSwab group.

Our results showed a higher sensitivity to detected CIN2+ in clinician-taken samples comparing to both self-sampling devices after 1 and 4 years. Specificity was higher in clinician-taken samples in the Qvintip group (57.8% vs. 45.5% after 1 year and 57.5% vs. 51.3% after 4 years) comparing to self-sampling; however, the specificity in the HerSwab group was slightly higher in self-sampling samples compared to clinician-taken samples (48.9% vs. 41.7% after 1 year and 47.7% vs. 44.4% after 4 years). This finding is consistent with most of reports indicating that HPV self-sampling has a lower sensitivity compared to clinician-taken samples and with of meta-analysis results published in 2014 by Arbyn et al., which included 36 studies and more than 154,500 women. Pooled sensitivity of HPV self-sampling to detect CIN2+ was 76% and specificity 86% while the pooled sensitivity and specificity of HPV testing on self-samples was lower than HPV testing with clinician-taken samples.22

In contrary, results of a Netherlands randomised study showed no difference between self-sampling and clinician-taken sampling of CIN2+ sensitivity (self-sampling 92.9%; clinician sampling 96.4%) and specificity (self-sampling 93.9%; clinician sampling 94.2%) of HPV testing.23

Arbyn’s meta-analysis was updated in 2017 and HPV tests were categorized into polymerase chain reaction (PCR) and signal amplification-based tests. HPV self-sampled assays based on PCR were as sensitive and specific on self-samples as on clinician samples to detect CIN2+. However, self-sampled HPV tests based on signal amplification were not as accurate for the detection of CIN2+.11

There was no statistically significant difference between the two testers used in our study regarding accordance to clinician-obtained HPV test. Other authors who compared Qvintip or HerSwab with other self-sampling devices for in their studies also did not find any differences in accordance to clinician-obtained samples.19,24

The concordance of self-performed vaginal samples and clinician-performed cervical samples has been the topic of a large number of studies. In our study, the agreement was lower as generally reported in literature, especially in the HerSwab group (OPA 77.1%, kappa 0.456) comparing to the Qvintip group (81.8%, kappa 0.534), although the difference between two testers was not statistically significant. In a 2005 meta-analysis by Ogilvie et al., data from 12 studies were included and kappa values between patients and clinician obtained samples ranged from 0.45-1.00.25 A systematic review and meta-analysis of 18 studies published in 2007 by Petignat et al., found a concordance between self-sampled and physician-sampled specimens for detection of HPV DNA in 87.0%, pooled kappa value of 0.66.26 Most recent studies reported OPA between vaginal self-obtained and cervical clinician-obtained samples for the detection of HPV to be between 91.2 and 96.8%.19,27, 28, 29, 30, 31, 32 The studies using the same self-sampling devices as in our study reported better agreement as well. In a German study, the Qvintip tester showed OPA with clinician collected sample in 89.0% (kappa 0.779), which is better than in our group of patients using the same type of self-sampling device (81.8%).19 El-Zein et al. reported a better agreement for HerSwab device with a kappa value of 0.84 compared to our group of patients (kappa 0.456).32

In a CASSIS study, HerSwab was used among others self-sampling devices and showed higher sensitivity (88.6%) and specificity (58.1%) than the one found in our study (77.6% and 48.9% after 1 year; 75.0% and 47.7% after 4 years).24 Sensitivity (92.4%) with clinician sampling was similar to ours and specificity (58.7%) was similar to that in our Qvintip group. In the same study, PPVs for CIN2+ were 28.0% and 29.7% for HerSwab and clinician taken samples respectively, which is quite lower compared to results in our group using the same self-sampling device (61.3% and 62.3% after 1 year; 62.9% and 66.7% after 4 years).24 The underlying reason is probably the different prevalence of the diseases. In our study, CIN2+ was diagnosed in 116 women (55.5%) one year after enrolment and four years after enrolment in 124 (59.3%) women. In a CASSIS study of 1217 women, 1076 had complete results for HPV and cytology; 148 (13.8%) had CIN1, 147 (13.7%) had CIN2/3, and 5 (0.5%) had cancer.

Relative sensitivity seems somehow higher in Qvintip compared to HerSwab, HPV self-sampling versus HPV test on clinician-taken samples (83.1/94.4 = 0.88 vs. 75.0/94.3 = 0.80) as well as in HPV self-sampling versus cytology (83.1/71.8 = 1.16 vs. 75.0/71.7 = 1.05). However, relative specificity seems slightly higher in HerSwab compared to Qvintip, HPV self-sampling versus HPV test on clinician-taken samples (51.3/57.5 = 0.89 vs. 47.7/44.4 = 1.07), as well as in HPV self-sampling versus cytology (51.3/75.0 = 0.68 vs. 47.7/46.7 = 1.02).

The sensitivity of cytology and HPV test on clinician-taken samples in our colposcopy study were similar between the Qvintip (71.8% and 94.4%) and HerSwab group (71.7% and 94.3%) and higher than in the recent Cochrane database systematic review of comparisons of HC2 results versus conventional cytology (ASC-US+ threshold) in the general population, where the pooled sensitivity of cytology was 62.5% and for HPV test on clinician-taken samples 89.9%.33

In a CASSIS study cytology ASC-US+ was 80.2% sensitive and 61.4% specific for CIN2+.24 The systematic review and meta-analysis in low and middle-income countries included more than 700 cervical cancers from 23 studies and found pooled sensitivity of cytology for cancer 79.4% at a cut-off HSIL+.34 On the other hand, Greek study authors reported about a very low sensitivity of cytology, 13.6% at cut-off HSIL.35

It is known that cervical cytology has limited sensitivity and that results may vary between different pathologists and laboratories and that HPV testing detects more cervical intraepithelial neo-plasia than cytology. Therefore, some countries (Netherlands, Great Britain) implemented HPV testing as a primary screening test.36, 37 Randomised clinical trials were conducted in many developed countries to evaluate primary HPV testing for cervical cancer screening in an organized program setting.

However, HPV testing has limitations. One of them is natural history of HPV infection, which is very common in young, sexually active women, but in majority of cases the infection is transient. Therefore, is not reasonable to use HPV testing for cervical screening in young women. Also, in elderly women positive HPV test does not necessarily imply the presence of precancerous cervical lesion. On the other hand, women with negative HPV test, have an extremely low risk of developing cervical cancer.

The European Guidelines do not recommend primary HPV screening before the age of 30 and are in favour of screening starting at the age of 35. Since HPV testing on self-taken samples is less accurate than on clinician-taken samples, self-sampling is recommended only for non-attenders in local settings.38 As HPV testing has a higher sensitivity than cytology in elderly population39, 40, 41, self-sampling and HPV testing may be a good alternative for non-attenders to cervical screening in this age group.

Self-sampling for HPV testing was less accurate compared to HPV testing on clinician-taken samples; however, there was no statistically significant difference between two testers used in our study. Conventional cytology was found to have a lower sensitivity for CIN2+ than HPV testing. Our study included relatively young women with an average age below 40 and we assume that the difference in sensitivity may be even greater in elderly population. The self-sampled HPV test is no less sensitive than cytology and can be safely applied in non-responders to the national ZORA program. However, this kind of screening might also be more suitable for women who used to attend regular gynaecological check-ups.