Alternative Colposcopy Techniques: A Systematic Review and Meta-analysis

Clinical application of photoacoustic imaging for cervical precursor lesion detection

PURPOSE

Early diagnosis of a precursor lesion in the uterine cervix is an essential factor in uterine cervical cancer prevention. Although colposcopy is an established procedure for detecting high-risk patients, its accuracy and reproducibility are relatively low. Some supportive or alternative techniques to improve the early diagnosis of a precursor lesion have been studied, and correct diagnosis with high reliability using a minimally invasive, cost-effective technique has been pursued. This study aimed to examine the possibility of using photoacoustic (PA) imaging as a supportive technique to improve the accuracy of early diagnosis of cervical precursor lesions.

METHODS

A PA imaging system for microvessels was used to detect angiogenesis in severe lesions. A total of 21 patients who underwent surgical treatment and 114 outpatients who visited our colposcopy clinic were examined. A retrospective evaluation of PA images was performed as follows: (i) pathological assessment of the specific PA findings and (ii) retrospective evaluation of the severe lesion detection rate through PA.

RESULTS

PA image evaluation and pathological findings showed dense angiogenesis in a severe precursor lesion appearing as a "hot spot" in the PA image. A comparison with colposcopy findings was performed for accuracy evaluation, and the detection rate of severe lesions using PA was relatively high (positive predictive value, 84.5%; negative predictive value, 82.1%).

CONCLUSION

Our results indicate the possibility of using PA imaging for early diagnosis of severe cervical precursor lesions. With its ability to yield quantitative information, PA imaging can improve ultrasound diagnosis.

Evolution of Pathological Techniques for the Screening of Cervical Cancer: A Comprehensive Review

The evolutionary journey of cervical cancer screening has been a major medical success story, considering the substantial role it has played in dwindling the disease burden. Through sustained collaborative efforts within the medical community, significant advances have been made from the humble yet path-breaking conventional Pap smear to the current automated screening systems and human papillomavirus (HPV) molecular testing. With the integration of artificial intelligence into screening techniques, we are currently at the precipice of circumventing the pitfalls of manual cytology readings and improving the efficiency of the screening systems by a significant margin. Despite the technological milestones traversed, the high logistics and operational cost, besides the technical know-how of operating the automated systems, can pose a major practical challenge in the widespread adoption of these advanced techniques in cervical cancer screening programs. This would suggest the need to adopt strategies that are tailored to the demands and needs of the different settings keeping their limitations in mind. This review aims to take the reader through the entire evolutionary journey of cervical cancer screening programs, highlight the individual merits and demerits of each technique, and discuss the recommendations from the major global guidelines.

A segmentation model to detect cevical lesions based on machine learning of colposcopic images

Background

Semantic segmentation is crucial in medical image diagnosis. Traditional deep convolutional neural networks excel in image classification and object detection but fall short in segmentation tasks. Enhancing the accuracy and efficiency of detecting high-level cervical lesions and invasive cancer poses a primary challenge in segmentation model development.

Methods

Between 2018 and 2022, we retrospectively studied a total of 777 patients, comprising 339 patients with high-level cervical lesions and 313 patients with microinvasive or invasive cervical cancer. Overall, 1554 colposcopic images were put into the DeepLabv3+ model for learning. Accuracy, Precision, Specificity, and mIoU were employed to evaluate the performance of the model in the prediction of cervical high-level lesions and cancer.

Results

Experiments showed that our segmentation model had better diagnosis efficiency than colposcopic experts and other artificial intelligence models, and reached Accuracy of 93.29 %, Precision of 87.2 %, Specificity of 90.1 %, and mIoU of 80.27 %, respectively.

Conclution

The DeepLabv3+ model had good performance in the segmentation of cervical lesions in colposcopic post-acetic-acid images and can better assist colposcopists in improving the diagnosis.

Near-Histologic Resolution Images of Cervical Dysplasia Obtained With Gabor Domain Optical Coherence Microscopy

OBJECTIVE

Histopathology is the criterion standard for evaluating cervical squamous intraepithelial neoplasia (dysplasia). In this pilot feasibility study, we examined whether a novel 3-dimensional imaging device using Gabor-domain optical coherence microscopy (GDOCM) could distinguish features of cervical dysplasia comparable with histopathology.

METHODS

A prospective observational pilot study enrolled a small sample of women undergoing loop electrosurgical excision procedure for cervical squamous intraepithelial neoplasia. Fresh ex vivo specimens were imaged with the GDOCM device. Digital images were reviewed by a pathologist who was blinded to the histopathology results. Histopathologic features were then compared with the digital observations.

RESULTS

Standard histologic features of cervical squamous epithelium and of squamous intraepithelial neoplasia could be observed in GDOCM images. Cervical epithelium, stroma, basement membrane, and squamous papilla could all be identified. Human papillomavirus effects, such as vacuolization and cellular density, were also observed.

CONCLUSIONS

A GDOCM imaging system has the potential to obtain histologic resolution images of the cervix in the evaluation of squamous intraepithelial neoplasia. This pilot study allowed for optimizing the imaging system and paved the way for a future diagnostic accuracy study. The development of this technology could streamline the evaluation of patients at risk for cervical neoplasia.

Screening test accuracy of portable devices that can be used to perform colposcopy for detecting CIN2+ in low- and middle-income countries: a systematic review and meta-analysis

BACKGROUND

Portable devices that can be used to perform colposcopy may improve cervical cancer screening in low- and middle-income countries (LMIC) where access to colposcopy is limited. The objective of this study was to systematically review the diagnostic test accuracy (DTA) of these devices for the detection of cervical intraepithelial neoplasia grade 2 or higher (CIN2+).

METHODS

In accordance with our protocol (Prospero CRD42018104286), we searched Embase, Medline and the Cochrane Controlled Register of Trials up to 9/2019. We included DTA studies, which investigated portable devices with moderate-to-high optical magnification (≥ 6×) for colposcopy, as described in the manual for Colposcopy and Treatment by the International Agency for Research on Cancer, with a histopathological reference standard. We used the QUADAS-2 tool to assess study quality. We examined results for sensitivity and specificity in paired forest plots, stratified by stages in the clinical pathway. We pooled estimates of test accuracy for the index test, used as an add-on to other tests, using a bivariate random-effect model.

RESULTS

We screened 1737 references and assessed 239 full-text articles for eligibility. Five single-gate DTA studies, including 2693 women, met the inclusion criteria. Studies evaluated two devices (Gynocular™ and Pocket) at different stages of the screening pathway. In three studies, which used the index test in an add-on capacity in 1273 women, we found a pooled sensitivity of 0.79 (95% CI 0.55-0.92) and specificity of 0.83 (95% CI 0.59-0.94). The main sources of bias were partial verification, incorporation and classification bias.

CONCLUSION

Few studies have evaluated portable devices able to perform colposcopy, so their accuracy for the detection of CIN2+ remains uncertain. Future studies should include patient-relevant and long-term outcomes, including missed cases, overtreatment, residual and recurrent disease. To meet the challenge of eliminating cervical cancer in LMIC, methods for visual assessment of the cervix need urgent redress.

Evaluation of the accuracy of colposcopy in detecting high-grade squamous intraepithelial lesion and cervical cancer

PURPOSE

The primary aim of this study was to evaluate the diagnostic accuracy of colposcopy in identifying high-grade squamous intraepithelial lesion or worse (HSIL+) and the characteristic performance of colposcopic images with various severity levels of cervical lesions.

METHODS

The medical records from 1828 women who underwent colposcopy at Affiliated Hospital of Tongji University from February 2016 to March 2019 were reviewed. Human papilloma virus (HPV) GenoArray test kit (HybriBio Ltd) and Thinprep cytologic test (TCT, Hologic, USA) were used to perform HPV genotyping and cytology. All colposcopic images were collected from the standard-of-care colposcope (Leisegang 3ML LED) and evaluated based on the 2011 International Federation of Cervical Pathology and Colposcopy (IFCPC) Colposcopy Standards. The linear by linear association, Pearson χ² test, χ² test, Kappa test, McNemar test and risk test were used to perform statistical analyses.

RESULTS

The consistency between colposcopy and biopsy pathology was 59.35% with the moderate strength of kappa coefficient of 0.464. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of colposcopy and cytology for HSIL+ were 56.29%, 93.82%, 77.47%, 85.04% and 37.13%, 98.49%, 90.29%, 80.58%, respectively. The colposcopic features of HSIL+ were as follows: (1) thick or bulgy acetowhite epithelium with sharp border; (2) completely nonstained of Lugol's iodine; (3) type III/IV/V of gland openings; (4) punctation or atypical vessels.

CONCLUSION

The data and findings herein provide the resource for evaluating the diagnostic value of colposcopy, and suggested that the accuracy of colposcopy is required to be further improved.

Nonlinear Optics with Near-Infrared Excitation Enable Real-Time Quantitative Diagnosis of Human Cervical Cancers

Histopathologic analysis through biopsy has been one of the most useful methods for the assessment of malignant neoplasms. However, some aspects of the analysis such as invasiveness, evaluation range, and turnaround time from biopsy to report could be improved. Here, we report a novel method for visualizing human cervical tissue three-dimensionally, without biopsy, fixation, or staining, and with sufficient quality for histologic diagnosis. Near-infrared excitation and nonlinear optics were employed to visualize unstained human epithelial tissues of the cervix uteri by constructing images with third-harmonic generation (THG) and second-harmonic generation (SHG). THG images enabled evaluation of nuclear morphology in a quantitative manner with six parameters after image analysis using deep learning. It was also possible to quantitatively assess intraepithelial fibrotic changes based on SHG images and another deep learning analysis. Using each analytical procedure alone, normal and cancerous tissue were classified quantitatively with an AUC ≥0.92. Moreover, a combinatory analysis of THG and SHG images with a machine learning algorithm allowed accurate classification of three-dimensional image files of normal tissue, intraepithelial neoplasia, and invasive carcinoma with a weighted kappa coefficient of 0.86. Our method enables real-time noninvasive diagnosis of cervical lesions, thus constituting a potential tool to dramatically change early detection. SIGNIFICANCE: This study proposes a novel method for diagnosing cancer using nonlinear optics, which enables visualization of histologic features of living tissues without the need for any biopsy or staining dye.

Cervical Cancer Screening: Past, Present, and Future

INTRODUCTION

Cervical cancer is the leading cause of cancer deaths in women in the developing world. New technologies have been developed to allow for more rapid, cost-effective, and sensitive cervical cancer screening and treatment.

AIM

The aim of this study was to describe methods for detection and treatment of human papillomavirus (HPV), cervical dysplasia (CD), and cervical cancer. New technologies and updated screening strategies will be emphasized.

METHODS

A literature search was conducted using PubMed to identify publications relevant to the subject.

MAIN OUTCOME MEASURE

Sensitivity and cost-effectiveness of new cervical cancer screening methods were the main outcome measures.

RESULTS

HPV and cervical cancer have a significant global impact. Research and innovations related to detection and treatment are key in reducing their burden worldwide.

CONCLUSION

Screening a woman for HPV and CD can dramatically decrease her risk of dying from cervical cancer. New, rapid, low-cost, HPV testing can allow for high-volume screening for the approximately 1.5 billion women who have never been screened. HPV screening can then be combined with high resolution digital colposcopy to detect CD. In the near future, these colposcopic images will be interpreted by artificial intelligence software. Detected lesions can then be treated easily and effectively with thermocoagulation. This see-and-treat model is a sensitive, efficient, and low-cost vision for the future. Bedell SL, Goldstein LS, Goldstein AR, et al. Cervical Cancer Screening: Past, Present, and Future. Sex Med Rev 2020;8:28-37.

Prospective cohort study examining cervical cancer screening methods in HIV-positive and HIV-negative Cambodian Women: a comparison of human papilloma virus testing, visualization with acetic acid and digital colposcopy

OBJECTIVES

Logistical and economic issues make traditional cytology-based cervical cancer screening challenging in developing countries. Alternative, cost-effective, screening strategies must be developed to screen millions of women in resource-poor countries such as Cambodia.

DESIGN

A prospective cohort study during which all women underwent four cervical cancer screening methods: (1) self-sampled human papilloma virus (HPV) testing (careHPV system), (2) clinician-collected HPV testing, (3) visualization with acetic acid (VIA) and (4) digital colposcopy (DC) with the Enhanced Visual Assessment System (EVA).

SETTING

A referral hospital in Phnom Penh, Cambodia.

PARTICIPANTS

Two hundred and fifty Cambodian women (129 HIV+, 121 HIV-). Subjects were recruited from the National Center for HIV/AIDS Dermatology and sexually transmitted disease (STD) cohort, the Sihanouk Hospital Center of Hope's Rural Outreach Teams and the Pochentong Medical Center.

RESULTS

Fifty six of the 250 (22.4%) patients tested positive for high-risk HPV (hrHPV+). Thirty seven of the 129 HIV+ women were hrHPV+ (28.6%) whereas 19/121 HIV- women were hrHPV+ (15.7%) p=0.0154. Self-sampling HPV specimens identified 50/56 (89%) whereas physician-collected specimens identified 45/56 (80%) p=0.174. 95.2% of the patients felt comfortable obtaining HPV self-samples. Thirty seven of 250 women were VIA+. Thirty of 37 VIA+ women underwent confirmatory biopsies for cervical intraepithelial neoplasia (CIN) (26 CIN1, 4 CIN2+). The rate of confirmed dysplasia in the HIV+ group was 20/129 (15.5%) compared with 10/121 (8.26%) in HIV- women p=0.0291. The contemporaneous physician impressions of the DC images accurately differentiated between CIN1 and CIN2+ lesions in all 30 women having confirmatory biopsies.

CONCLUSIONS

The results of this study suggest potential modifications of the current cervical screening strategy that is currently being employed in Cambodia. The first step in this new strategy would be self-swabbing for hrHPV. Subsequently, hrHPV+ patients would have DC and immediate treatment based on colposcopic findings: cryotherapy for suspected CIN1 and loop electrosurgical excision procedure (LEEP) for suspected CIN2+.

Multimodal Hyperspectroscopic Imaging for Detection of High-Grade Cervical Intraepithelial Neoplasia

OBJECTIVE

Numerous new alternative digital colposcopy techniques have been developed, of which multimodal hyperspectroscopy (MHS) showed a high sensitivity in previous studies. The objective of this prospective single-center cohort study was to evaluate the clinical value of MHS for detecting high-grade cervical intraepithelial neoplasia in a colposcopy referral population and colposcopy follow-up population, to assess whether MHS could be safely used to improve care for women at risk for high-grade cervical intraepithelial neoplasia.

MATERIALS AND METHODS

A total of 125 women from a colposcopy referral population and colposcopy follow-up population were evaluated with MHS and tested for the presence of high-risk human papillomavirus (HPV) with HPV-16/18 genotyping. Spectroscopic measurements of the cervix were taken and compared with an end point based on histology, high-risk HPV, and cytology. Evaluable data for analysis were collected from 102 of the subjects. Sensitivity, specificity, and predictive values were calculated for MHS and colposcopic impression based on conventional colposcopic examination.

RESULTS

From the total study population of the 102 patients, 47 were enrolled in the colposcopy referral group and 55 in the colposcopy follow-up group. The MHS yielded a sensitivity of 93.6% (95% CI = 78.6-99.2), with a corresponding specificity of 42.3% (95% CI = 30.6-54.6) in the group with a composite end point. No adverse effects occurred, and patient acceptability was high.

CONCLUSIONS

Multimodal hyperspectroscopy is a digital colposcopy technique that offers an easy, rapid, well-tolerated point-of-care assessment with a high sensitivity for the presence of high-grade cervical intraepithelial lesions, however, with a low specificity, resulting in limited clinical value.