Evaluation of cytology versus human papillomavirus-based cervical cancer screening algorithms in Bhutan

Population-level cancer screening and cancer care in Bhutan, 2020-2023: a review

Screening of cancers is an important intervention in reducing the incidence and mortality related to cancers. Bhutan is one small country that is witnessing an increasing incidence and mortality related to cancers. The government implemented a time-bound population-level screening for gastric, cervical and breast cancers from 2020 to 2023 with an overall coverage of 91.2% of the eligible population. Among 370,225 individuals screened for H pylori, 32.4% tested positive; among 53,182 who underwent upper gastrointestinal endoscopy and biopsy, 255 (0.07%) had gastric cancer. Among 10,749 tested for HPV DNA, 9.3% were positive; among 9887 evaluated with colposcopy and biopsy, 154 (0.13%) had cervical cancer. For breast cancer screening, 72,283 underwent clinical breast examination, 845 mammography and cancer was detected in 73 (0.10%) individuals. In this article, we review how Bhutan implemented a population-level cancer screening programme with on boarding of multiple stakeholders and the participation of people across all districts.

Human papillomavirus testing on self-collected samples to detect high-grade cervical lesions in rural Bhutan: The REACH-Bhutan study

BACKGROUND

"REACH-Bhutan" aimed to evaluate the feasibility and clinical performance of a community-based screening program for cervical cancer in rural Bhutan using self-collected samples for high-risk human papillomavirus (HR-HPV) testing.

METHODS

In April/May 2016, 2590 women aged 30-60 years were screened across rural Bhutan by providing a self-collected sample for careHPV testing. All careHPV-positive women, plus a random sample of careHPV-negative women, were recalled for colposcopy and biopsy. Self-samples also underwent GP5+/6+ polymerase chain reaction (PCR)-based HR-HPV DNA detection and genotyping. Cross-sectional screening indices were estimated against histological high-grade squamous intraepithelial lesions or worse (hHSIL+), including imputation of hHSIL+ in women without colposcopy.

RESULTS

HR-HPV positivity was 10.2% by careHPV and 14.8% by GP5+/6+ PCR. Twenty-two cases of hHSIL+ were histologically diagnosed, including one invasive cancer; an additional 7 hHSIL+ were imputed in women without colposcopy. HR-HPV testing by GP5+/6+ showed higher sensitivity for hHSIL+ (89.7%, 95% CI 72.6-97.8) than careHPV (75.9%, 95% CI 56.5-89.7). Negative predictive value was also slightly higher for GP5+/6+ (99.9%, 95% CI 99.6-100) than careHPV (99.7%, 95% CI 99.4-99.9). Specificity, however, was lower for GP5+/6+ (86.1%, 95% CI 84.6-87.4) than careHPV (90.6%, 95% CI 89.4-91.7), as was positive predictive value (6.9%, 95% CI 4.5-9.9 vs. 8.5%, 95% CI 5.4-12.6). Of 377 HR-HPV-positive women by GP5+/6+, 173 (45.9%) were careHPV-positive, including 54.7% HPV16-positive and 30.2% HPV18-positive women.

CONCLUSIONS

The final REACH-Bhutan results show that screening for cervical cancer with self-collection of samples and HR-HPV testing, in addition to our previous report of achieving high participation, can also perform well to detect women with hHSIL+.

Gender-neutral HPV elimination, cervical cancer screening, and treatment: Experience from Bhutan

Cervical cancer is preventable and also curable when detected early and treated adequately, yet it remains a leading cause of morbidity and mortality among women. In Bhutan, cervical cancer is the most common cancer among women. Bhutan was the first country among the low- and middle-income economies to have instituted a national HPV vaccination program, in 2010, and has achieved >90% coverage. In 2019, Bhutan launched a cervical cancer elimination flagship program well ahead of WHO's launch of the global strategy for accelerated elimination of cervical cancer. Bhutan initiated vaccination of adolescent boys and adopted a gender-neutral vaccination program beginning September 2020 through its well-established network of primary healthcare centres. The flagship program aims to screen women aged 30-69 years with HPV testing using liquid-based cytology (LBC) as triaging for screen positive women. For women aged 25-29 years, LBC will be continued as per American Society of Colposcopy and Cervical Pathology guidelines. Colposcopy and treatment will be performed in camps to decrease loss of follow up of screen positive women. This program is also expected to improve early diagnosis of cervical cancer and provide timely and adequate cancer treatment and palliative care services. This article reviews the progress made and the challenges facing the 2030 cervical cancer elimination targets in Bhutan.

How to triage HPV positive cases: Results of four million females

OBJECTIVE

To evaluate the Turkey's nationwide HPV DNA screening program on the basis of first 4 million screened women.

METHODS

Women over age 30 were invited for screening via HPV DNA and conventional cytology. Single visit screen strategy was used to collect for both screening and triage (extended genotyping and conventional pap-smear).

RESULTS

A total of 4,099,230 patients had attended to HPV DNA cancer screening. 4.39% were found to be HPV DNA positive. The most common HPV type was 16, followed by 51, 31, 52, 56 and 18 at all age intervals and geographic regions. Cytology results were reported as "normal" in (69.2%), "inadequate sampling" in (16.6%) and as "abnormal (≥ASC-US)" in the remaining. Current Turkish screening with HPV DNA (referral to colposcopy with HPV 16 or 18 or any smear abnormality ≥ASC-US) gives overall PPV of 24.3% for ≥CIN2. Only Pap-Smear triage revealed PPV of 26.4% for ≥ASC-US thresholds. Comparison of different triage methods for ≥CIN2+ according to different HPV genotype revealed a PPV of 32,6% for HPV 16; 15,3% for HPV 18. This figure was 34.4%, 19.3%, 15.3% and 14.0% for HPV 33, 31, 45 and 35; respectively.

CONCLUSION

This study involves the largest series in the world summarizing a real-world experience with primary HPV DNA screening and triage with a single visit. The results show the feasibility and applicability of such screening method in developing countries with acceptable colposcopy referral rates. Among triage tests, only pap-smear seems to be effective without a need for extended genotyping.

An on-going study of three different cervical cancer screening strategies based on primary healthcare facilities in Beijing China

BACKGROUND

To evaluate and compare the results of three different cervical cancer screening strategies including cytology screening, HR-HPV screening which taking HR-HPV testing as primary test and co-testing which taking both tests at the same time, then provide evidence to explore whether the cervical cancer screening can be conducted in community healthcare centers in Beijing.

METHODS

182,119 women aged between 35 and 64, who were screened in the primary healthcare facilities of nine districts in Beijing from January 2014 to March 2015, were enrolled in this study. Cytology screening was performed in participants during January 2014 and December 2014 as a conventional arm. HR-HPV screening strategy and co-testing were randomly allocated to participants on districts level as experimental arm 1 and 2 during January 2015 and March 2015. Cervical Intraepithelial Neoplasia grade 2 or worse (CIN 2+) was defined as endpoint. The screening results and costs to detect a case of three strategies were calculated.

RESULTS

The positivity rate, colposcopy referral rate and biopsy referral rate of co-testing were 8.46%, 6.36% and 4.65% respectively, which were all significantly higher than the other two screening strategies. The detection rate of CIN 2+ by co-testing was 5.06‰ and was much more than the other two screening strategies, while the HR-HPV screening had the highest PPV of 14.40%. The HR-HPV screening ignores some lesion which can be found by co-testing. Co-testing refers a woman to colposcopy with a positive screening result at the least cost, but it costs the most to detect a CIN 2+ case.

CONCLUSIONS

To detect more cases of CIN 2+, co-testing performs better although with the most cost. And the primary healthcare facilities in Beijing have the capability to carry out the cervical cancer screen programs and prompts women with positive screen results to the hospital.

Comparison between self sampling and provider collected samples for Human Papillomavirus (HPV) Deoxyribonucleic acid (DNA) testing in a Nigerian facility

Introduction

The multiple visits required for an effective Pap smear screening program is difficult to replicate in many developing countries. This precludes early diagnosis and care for patients with cervical cancer and contributes to its high mortality in these countries. HPV screening has higher specificity and high negative predictive value and has the advantage that materials can be self-collected, which permits the screening of women who for various cultural and religious reasons would be reluctant to come to the clinic to expose themselves for screening. The aim of the study was to assess the degree of agreement between self sampling for HPV DNA with samples collected by a health provider.

Methods

Each respondent selected from women presenting for cervical cancer screening underwent both self- and provider sampling for HPV DNA testing using Hybribio GenoArray.

Results

Of the 194 women screened, 12 (6.2%) and 19 (9.8%) had HPV on self sampling and provider col-lected samples respectively. The commonest HPV type seen using both techniques was HPV 58 (2.6%). Multiple HPV genotypes were seen in 1 (0.5%) and 5 cases (2.6%) of provider and self-collected samples respectively. The high risk-HPV detection rate was 7.2% when self sampled and 6.8% when sampled by the provider. There was moderate correlation between both sampling techniques (κ = 0.47, 95% CI: 21.3 - 72.3%, P < 0.05).

Conclusion

Our study shows moderate correlation between both sampling techniques. Larger multicentre studies will be needed to provide results generalisable to the Nigerian population. Keywords: Pap smear, HPV screening, cervical cancer, sample collection, self-sampling, provider collected, PCR, HPV DNA, Ile-Ife Nigeria.

Evaluation of human-papillomavirus testing and visual inspection for cervical cancer screening in Rwanda

BACKGROUND

A pilot screening campaign in Rwanda, based on careHPV-testing followed by visual inspection with acetic acid triage (careHPV+VIA triage), was evaluated against other WHO-recommended screening options, namely HPV screen-and-treat and VIA screen-and-treat.

METHODS

764 women aged 30-69 underwent at visit 1: i) VIA, and cervical cell collection for ii) careHPV in Rwanda, and iii) liquid-based cytology and GP5+/6+ HR-HPV PCR in The Netherlands. All 177 women positive by VIA, careHPV and/or PCR were recalled, of whom 84% attended. At visit 2, VIA was again used to triage screen-positive women for treatment and to obtain biopsies from all women either from visible lesions or at 12 o'clock of the squamocolumnar junction. Cross-sectional screening indices were estimated primarily against histological high-grade squamous intraepithelial lesions or worse (hHSIL+), after imputation of missing histology data, based on 1-visit or 2-visit approaches.

RESULTS

In a 1-visit screen-and-treat approach, VIA had sensitivity and specificity of 41% and 96%, respectively, versus 71% and 88% for careHPV, and 88% and 86% for PCR. In a 2-visit approach (in which hHSIL+ imputed among women without visit 2 were considered untreated) careHPV sensitivity dropped to 59% due to loss of 13% of hHSIL+. For careHPV+VIA triage, sensitivity dropped further to 35%, as another 24% of hHSIL+ were triaged to no treatment.

CONCLUSIONS

CareHPV was not as sensitive as gold-standard PCR, but detected considerably more hHSIL+ than VIA. However, due to careHPV-positive hHSIL+ women being lost to follow-up and/or triaged to no treatment, 2-visit careHPV+VIA triage did not perform better than VIA screen-and-treat.