Rebecca Richards-Kortum

Multiscale Optical Imaging Fusion for Cervical Precancer Diagnosis: Integrating Widefield Colposcopy and High-Resolution Endomicroscopy

Early detection and treatment of cervical precancers can prevent disease progression. However, in low-resource communities with a high incidence of cervical cancer, high equipment costs and a shortage of specialists hinder preventative strategies. This manuscript presents a low-cost multiscale in vivo optical imaging system coupled with a computer-aided diagnostic system that could enable accurate, real-time diagnosis of high-grade cervical precancers. The system combines portable colposcopy and high-resolution endomicroscopy (HRME) to acquire spatially registered widefield and microscopy videos. A multiscale imaging fusion network (MSFN) was developed to identify cervical intraepithelial neoplasia grade 2 or more severe (CIN 2+). The MSFN automatically identifies and segments the ectocervix and lesions from colposcopy images, extracts nuclear morphology features from HRME videos, and integrates the colposcopy and HRME information. With a threshold value set to achieve sensitivity equal to clinical impression (0.98 [p = 1.0]), the MSFN achieved a significantly higher specificity than clinical impression (0.75 vs. 0.43, p = 0.000006). Our findings show that multiscale optical imaging of the cervix allows the highly sensitive and specific detection of high-grade precancers. The multiscale imaging system and MSFN could facilitate the accurate, real-time diagnosis of cervical precancers in low-resource settings.

Single-tube four-target lateral flow assay detects human papillomavirus types associated with majority of cervical cancers

Isothermal nucleic acid amplification methods have many advantages for use at the point of care. However, there is a lack of multiplexed isothermal amplification tests to detect multiple targets in a single reaction, which would be valuable for many diseases, such as infection with high-risk human papillomavirus (hrHPV). In this study, we developed a multiplexed loop-mediated isothermal amplification (LAMP) reaction to detect the three most common hrHPV types that cause cervical cancer (HPV16, HPV18, and HPV45) and a cellular control for sample adequacy. First, we characterized the assay limit of detection (LOD) in a real-time reaction with fluorescence readout; after 30 min of amplification the LOD was 100, 10, and 10 copies/reaction of HPV16, HPV18, and HPV45, respectively, and 0.1 ng/reaction of human genomic DNA (gDNA). Next, we implemented the assay on lateral flow strips, and the LOD was maintained for HPV16 and HPV18, but increased to 100 copies/reaction for HPV45 and to 1 ng/reaction for gDNA. Lastly, we used the LAMP test to evaluate total nucleic acid extracted from 38 clinical samples; compared to qPCR, the LAMP test had 89% sensitivity and 95% specificity. When integrated with sample preparation, this multiplexed LAMP assay could be useful for point-of-care testing.

An integrated isothermal nucleic acid amplification test to detect HPV16 and HPV18 DNA in resource-limited settings

High-risk human papillomavirus (HPV) DNA testing is widely acknowledged as the most sensitive cervical cancer screening method but has limited availability in resource-limited settings, where the burden of cervical cancer is highest. Recently, HPV DNA tests have been developed for use in resource-limited settings, but they remain too costly for widespread use and require instruments that are often limited to centralized laboratories. To help meet the global need for low-cost cervical cancer screening, we developed a prototype, sample-to-answer, point-of-care test for HPV16 and HPV18 DNA. Our test relies on isothermal DNA amplification and lateral flow detection, two technologies that reduce the need for complex instrumentation. We integrated all test components into a low-cost, manufacturable platform, and performance of the integrated test was evaluated with synthetic samples, provider-collected clinical samples in a high-resource setting in the United States, and self-collected clinical samples in a low-resource setting in Mozambique. We demonstrated a clinically relevant limit of detection of 1000 HPV16 or HPV18 DNA copies per test. The test requires six user steps, yields results in 45 min, and can be performed using a benchtop instrument and minicentrifuge by minimally trained personnel. The projected per-test cost is <$5, and the projected instrumentation cost is <$1000. These results show the feasibility of a sample-to-answer, point-of-care HPV DNA test. With the inclusion of other HPV types, this test has the potential to fill a critical gap for decentralized and globally accessible cervical cancer screening.

One-hour extraction-free loop-mediated isothermal amplification HPV DNA assay for point-of-care testing in Maputo, Mozambique

Abstract Human papillomavirus (HPV) is responsible for nearly all cases of cervical cancer. Affordable point-of-care DNA testing is needed for cervical cancer screening in low- and middle-income countries, where most cervical cancer cases occur. HPV DNA testing typically requires complex lab infrastructure and trained personnel. In this work, we develop a loop-mediated isothermal amplification (LAMP)-based HPV DNA test, which targets three of the most oncogenic HPV types (HPV16, HPV18, HPV45) and a cellular control and achieves analytical sensitivity comparable to gold standard methods. Our extraction-free sample preparation strategy permits adding sample lysate directly to the LAMP reaction. We utilize a low-cost benchtop heater/fluorimeter, delivering results in less than one hour. We analytically evaluate our assay with clinical samples in Houston, Texas (n = 38) and Maputo, Mozambique (n = 191). Results show 100% and 93% concordance, respectively, with a reference test widely used in low-resource settings. This sensitive and specific four-step assay can potentially expand cervical cancer screening in resource-limited settings.

A randomized clinical trial to assess the effectiveness of thermal ablation versus loop electrosurgical excision procedure for cervical cancer risk reduction in women living with HIV in Mozambique.

Cervical cancer remains a leading cause of death in low- and middle-income countries. Women living with human immunodeficiency virus (HIV) carry a 6-fold higher risk of cervical cancer than the general population. The effectiveness of thermal ablation versus loop electrosurgical excision procedure (LEEP) in women living with HIV is uncertain, prompting this study. To compare the effectiveness of thermal ablation versus LEEP for the management of abnormal cervical cancer screening results in women living with HIV. Thermal ablation is non-inferior to LEEP for treatment of cervical intra-epithelial neoplasia (CIN) 2/3 and high-risk human papillomavirus (hrHPV) infection in women living with HIV. This is a prospective randomized clinical trial. Participants undergo screening with primary hrHPV testing. Those with positive hrHPV results undergo visual inspection with acetic acid and a review of genotyping results to determine eligibility for treatment. Those who are hrHPV-positive and positive by visual assessment with acetic acid, or human papillomavirus16/18 positive regardless of visual assessment with acetic acid result, are randomized to thermal ablation or LEEP. Participants undergo follow-up at 4 to 8 weeks, 6 months, and 12 months post-procedure. Participants include 25 to 49-year-old women living with HIV in Mozambique. Exclusion criteria include pregnancy, previous total hysterectomy, history of cervical cancer or prior treatment for CIN, or any condition that would preclude adherence to the study protocol. Persistent or recurrent CIN 2/3 (or worse diagnosis) and hrHPV infection at 12 months after initial treatment. To meet our primary objectives and to achieve a power of 0.8 (α = 0.025), we will need to randomize 126 participants with CIN 2/3, 63 to thermal ablation, and 63 to LEEP. We estimate that this will require screening a total of 4844 women living with HIV. We anticipate that study accrual will be completed in 3 years (2027), with an additional 18 months to complete all follow-up visits and data analysis. We anticipate presenting results in 2029. ClinicalTrials.gov #NCT06326294.

Scaling cervical cancer screening in Mozambique: analysis of loop electrosurgical excision procedure (LEEP) specimens

As cervical cancer screening programs are implemented and expanded, an increasing number of women require loop electrosurgical excision procedure (LEEP) for treatment of pre-invasive cervical disease. Our objective was to describe the pathological results of LEEP specimens performed as part of the MULHER study and identify factors associated with positive LEEP margins. The MULHER study enrolled 9014 women who underwent HPV testing followed by visual assessment for treatment (VAT) using visual inspection with acetic acid (VIA) and thermal ablation for those with positive results. Participants with lesions ineligible for ablation underwent LEEP. Pathology reports were reviewed for specimen size/volume, number of fragments, pathological diagnosis and margin status. Multivariable regression analysis was performed to identify variables associated with positive LEEP margins. 169 participants underwent LEEP. The median age was 38 years (range 30-49). 65.1% were women living with HIV. Pathological diagnosis was available for 154 patients and included cancer (n=6, 3.9%); cervical intraepithelial neoplasia (CIN) 2/3 (n=75, 48.7%); CIN 1 (n=67, 43.5%); and normal/benign findings (n=6,3.9%). 31.8% of LEEP specimens were removed in more than one fragment. The mean specimen volume was 2.9 cm Our results showed a high number of LEEP specimens with positive margins. Additional evaluation is needed to better understand the characteristics of precancerous cervical lesions in this high-risk population. As cervical cancer screening programs are scaled in Mozambique and other lower-resource countries, there is a need to train providers to perform high-quality LEEP and for accurate and timely pathological interpretation.