Statistical Modeling for Quality Assurance of Human Papillomavirus DNA Batch Testing

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+.

Reproducibility of a Rapid Human Papillomavirus Test at Different Levels of the Healthcare System in Tanzania: The AISHA Study

BACKGROUND

To inform policy makers in Tanzania if and how best to implement rapid HPV testing, we assessed the interobserver reproducibility of careHPV test at three different levels of the healthcare system in an urban and a rural region of Tanzania.

METHODS

Women aged 30 to 50 years were screened by careHPV testing in two primary healthcare centers (PHC), two district hospitals (DiH), and two regional hospitals (ReH). Aliquots were retested at regional (ReH) and national referral laboratories (NRL). Reproducibility was evaluated using agreement and kappa index measures. Intralaboratory reproducibility was also evaluated in a set of 10 positive and 10 negative samples.

RESULTS

Samples from 1,134 women were locally tested and retested at ReH and/or NRL. Test results from Dar es Salaam ReH and Kilimanjaro PHC showed clear quality problems including suspicion of contamination during testing or aliquoting. After excluding these samples, 18.8% of 743 women were HPV positive at clinic level. The resulting careHPV reproducibility at different levels of the healthcare system was very good [agreement 95.7%, 95% confidence interval (CI), 94.0-96.9; kappa, 0.86, 95% CI, 0.81-0.91]. Intralaboratory agreement was also very good across four different experiments, with Fleiss' kappa between 0.87 (95% CI, 0.61-1.00) and 1.00 (0.75-1.00).

CONCLUSIONS

Rapid HPV testing was highly reproducible between lower and higher levels of the healthcare system in Tanzania; however, performance seems to be operator dependent.

IMPACT

The careHPV test seems to be a feasible option for cervical cancer screening in an organized, decentralized system and in limited-resource settings if quality assurance measures are in place.

Introduction of HPV testing for cervical cancer screening in Central America: The Scale-Up project

The Scale-Up project introduced vaginal self-sampling and low-cost human papillomavirus (HPV) testing as the primary approach for cervical cancer screening in selected public health centers in Guatemala, Honduras, and Nicaragua. We evaluate the country-specific accomplishments in screening: target-coverage, triage, and treatment. Between 2015 and 2018, cervical cancer screening was offered to women at least 30 years of age. Triage of HPV-positive women was based on visual inspection with acetic acid or Pap. Aggregated data included total women screened, use of self-sampling, age, time elapsed since last screening, HPV results, triage tests, triage results, and treatment. A total of 231,741 women were screened for HPV, representing 85.8% of the target populations within the project. HPV positivity was lower in Guatemala (12.4%) compared to Honduras and Nicaragua (14.5% and 14.2%, respectively, p < 0.05). A follow-up triage test was completed for 84.2%, 85.8%, and 50.1% of HPV-positive women in Guatemala, Nicaragua, and Honduras, respectively. Of those with a positive triage test, 84.7%, 67.1%, and 58.8% were treated in Guatemala, Nicaragua, and Honduras, respectively. First-time screening was highest in Nicaragua (55.8%) where self-sampling was also widely used (97.1%). The Scale-Up project demonstrated that large-scale cervical cancer screening and treatment intervention in a high-burden, low-resource setting can be achieved. Self-sampling and ablative treatment were key to the project's achievements. Data monitoring, loss to follow-up, and triage methods of screen- positive women remain critical to full success.