In vivo detection of human papilloma virus-induced lesions of anogenital area after application of acetic acid: a novel and accurate approach to a trivial method

Optimization of Classification Strategies of Acetowhite Temporal Patterns towards Improving Diagnostic Performance of Colposcopy

Efforts have been being made to improve the diagnostic performance of colposcopy, trying to help better diagnose cervical cancer, particularly in developing countries. However, improvements in a number of areas are still necessary, such as the time it takes to process the full digital image of the cervix, the performance of the computing systems used to identify different kinds of tissues, and biopsy sampling. In this paper, we explore three different, well-known automatic classification methods (k-Nearest Neighbors, Naïve Bayes, and C4.5), in addition to different data models that take full advantage of this information and improve the diagnostic performance of colposcopy based on acetowhite temporal patterns. Based on the ROC and PRC area scores, the k-Nearest Neighbors and discrete PLA representation performed better than other methods. The values of sensitivity, specificity, and accuracy reached using this method were 60% (95% CI 50–70), 79% (95% CI 71–86), and 70% (95% CI 60–80), respectively. The acetowhitening phenomenon is not exclusive to high-grade lesions, and we have found acetowhite temporal patterns of epithelial changes that are not precancerous lesions but that are similar to positive ones. These findings need to be considered when developing more robust computing systems in the future.

Estimation of neoplasia-related biological parameters through modeling and sensitivity analysis of optical molecular imaging data

We combine system's biology approaches with in vivo optical molecular imaging of epithelial neoplasia for estimating disease-specific biological parameters. Molecular imaging measures and maps the dynamic optical effects, generated by the topical application of acetic acid diluted solution. The dynamic characteristics of the in vivo measured optical signal are governed by the epithelial transport effects of the biomarker. Nine biological parameters, both structural and functional, have been identified to be potentially correlated with the neoplasia growth and to be manifested to the measured data in a convoluted manner. A compartmental model of the cervical neoplastic epithelium has been developed, which predicts the dynamic optical effects in all possible parameter value combinations. We have performed global sensitivity analysis for the purpose of identifying the subset of the input parameters that are the key determinants of the model's output. Finally, we have for the first time shown that it is possible to estimate, from in vivo measured dynamic optical data, the following neoplasia related parameters: number of neoplastic layers, intracellular and extracellular space dimensions, functionality of tight junctions, and extracellular pH. These findings have been (in part) validated with optical data and biopsies obtained from 30 women with cervical neoplasia.

Treatment of carcinoma in situ of the glans penis with topical chemotherapy agents

BACKGROUND

The use of topical agents in the treatment of carcinoma in situ (CIS) of the penis has been well described in the literature. Previous studies have been limited by small sample size and imprecise end points.

OBJECTIVE

Establish the response rate of 5-fluorouracil (5-FU) and imiquimod (IQ) in the treatment of penile CIS in a large contemporary series in a supranetwork centre.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective review of all primary and recurrent cases of penile CIS treated with 5-FU and IQ identified from a prospective database over a 10-yr period. Therapy was standardised in all cases with application to the lesion for 12h every 48 h for 28 d.

INTERVENTION

5-FU was the first-line therapy, and IQ was the second-line topical agent.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary end point was defined as complete response (CR; i.e., resolution of lesion), partial response (PR; i.e., lesion reduced in size and or visibility), or no response (NR; ie, no improvement in lesion size and or visibility). The secondary end points included local toxicity and adverse events. No statistical analysis or software was used.

RESULTS AND LIMITATIONS

A total of 86 patients were diagnosed with CIS of the penis over the 10-yr period. Forty-four (51%) received topical chemotherapy. The mean follow-up was 34 mo. CR to topical chemotherapy was seen in 25 (57%), PR was seen in 6 (13.6%), and NR was seen in the remaining 13 (29.5%) patients. Local toxicity was experienced by 10% of patients, and 12% had an adverse event following application of 5-FU. The retrospective design and short follow-up were the major limitations of this study.

CONCLUSIONS

Topical chemotherapy agents are moderately effective first-line therapy in the treatment of penile CIS. Toxicity and adverse events were few with our treatment protocol. The issues of long-term surveillance and assessment of partial responders remain a challenge. Topical chemotherapy should remain a first-line treatment option for penile CIS.

In vivo dynamic imaging, in silico modeling and global sensitivity analysis for the study and the diagnosis of epithelial neoplasia

We present a method for detecting and studying neoplasia-specific functional and structural features through the combination of in vivo dynamic imaging, in silico modeling and global sensitivity analysis. We particularly present the case of cervical epithelium interacting with acetic acid solution, which is employed as an optical biomarker. The in vivo measured dynamic scattering characteristics are strongly correlated with the output of the biomarker's pharmacokinetic model that we have developed. Model global sensitivity analysis has shown that the measured/modeled bio-optical processes can be used for probing, in vivo, the number of neoplastic layers, the extracellular pH, the intracellular buffering efficiency and the size of the extracellular space.

Aceto-white temporal pattern classification using k-NN to identify precancerous cervical lesion in colposcopic images

After Pap smear test, colposcopy is the most used technique to diagnose cervical cancer due to its higher sensitivity and specificity. One of the most promising approaches to improve the colposcopic test is the use of the aceto-white temporal patterns intrinsic to the color changes in digital images. However, there is not a complete understanding of how to use them to segment colposcopic images. In this work, we used the classification algorithm k-NN over the entire length of the aceto-white temporal pattern to automatically discriminate between normal and abnormal cervical tissue, reaching a sensitivity of 71% and specificity of 59%.

The diagnostic accuracy of colposcopy in previously treated cervical intraepithelial neoplasia

OBJECTIVE

To determine whether colposcopy is reliable in diagnosing cervical intraepithelial neoplasia in women who have undergone a previous cervical excision biopsy.

MATERIALS AND METHODS

A prospective study of women attending the colposcopy clinic at the University Hospital of North Staffordshire was performed between January 1998 and December 1999.

RESULTS

A clear histological diagnosis of the grade of cervical intraepithelial neoplasia was available for 469 in the treatment-naive group and 58 in the treatment group. kappa coefficients comparing the colposcopic impression (negative, low-grade, high-grade, or invasion) with histological diagnosis showed that there was no difference between the treatment-naive group, weighted kappa=0.46, and the previous treatment group, weighted kappa=0.47. The sensitivity, specificity, positive predictive value, and negative predictive value of colposcopy for any cervical disease in the treatment-naive women were 93.9%, 51.9%, 96.7%, and 34.1%, respectively, compared with 77.6%, 66.7%, 86.4%, and 35.3% in previously treated women. The sensitivity of colposcopy fell when it was used to differentiate normal and low-grade disease from high-grade disease and invasion: 82.4%, 55.9%, 82.6%, and 49.6% for treatment-naive women, compared with 61.5%, 84.2%, 60.0% and 51.6%, respectively, for the previous treatment group.

CONCLUSIONS

Previous treatment to the cervix does not seem to impair the ability of colposcopy to differentiate normal cervix from all grades of cervical abnormality in women where the squamocolumnar junction is visible. However, there is a suggestion that the sensitivity of colposcopy to differentiate negative/low-grade disease from high-grade disease/invasion is lower in previously treated women.

Prevalence of genital human papillomavirus infections established using different diagnostic techniques among males attending a urological clinic

OBJECTIVE

To compare the accuracy of different diagnostic methods and their use in estimating the prevalence of genital human papillomavirus (HPV) infections in males attending a urological clinic.

MATERIAL AND METHODS

The study population was derived from a series of 1,153 consecutive males attending a urological clinic in São Paulo between January 1996 and November 1998. Of these 1,153 males, 334 had clinically suspected genital HPV infection and comprised the study cohort. The diagnostic methods used included peniscopy, directed biopsy and HPV detection by means of the Hybrid Capture 2 (HC) assay for both oncogenic and non-oncogenic HPV types.

RESULTS

Peniscopy was performed for 297 males, positive results being reported in 237 cases (79.8%). Directed biopsy was performed in 188 males, and histology suggested HPV in 140 of these cases (74.5%). HC confirmed the presence of HPV in only 35.2% of the histologically HPV-suggestive cases. Peniscopy has good sensitivity for identifying male carriers of genital HPV. However, the technique has an inherent low specificity, limiting its usefulness to the correct identification of those who never present with HPV infection. Characteristic histological alterations are useful in suggesting HPV infection, but their correlation with HPV detection using HC is not particularly good.

CONCLUSIONS

These data suggest that both histology and peniscopy have low specificity in detecting male genital HPV. Accurate diagnosis of HPV infection can be confirmed by molecular detection methods only. Histology, however, plays an important role in the differential diagnosis. An appropriate diagnostic protocol for male genital HPV infections in a urological clinic should include peniscopy, histology and molecular diagnostic tools (HC or polymerase chain reaction).

In vivo fluorescence kinetics and photodynamic therapy in condylomata acuminata

BACKGROUND

Topical application of 5-aminolaevulinic acid (ALA) to condylomata acuminata leads to accumulation of protoporphyrin IX (PpIX); therefore ALA-induced photodynamic therapy (ALA-PDT) appears to be a potential treatment.

OBJECTIVES

To investigate in vivo the PpIX fluorescence time course after topical application of ALA in order to determine the optimal time for irradiation, and to assess the efficacy of subsequently performed ALA-PDT.

METHODS

Fluorescence kinetics was studied in 12 male patients with condylomata acuminata. Confirmation of diagnosis was established with conventional histology and polymerase chain reaction. Lesions were treated with 20% ALA and irradiated at the optimal time with a dose of 70 J cm-2 or 100 J cm-2 light. An additional session with 100 J cm-2 was administered 1 week later to lesions that persisted.

RESULTS

The in vivo study of fluorescence kinetics indicated that the optimal time for irradiation varied among patients from 6 to 11 h. The overall cure rate was 72.9%, 12 months after treatment.

CONCLUSIONS

Topical ALA-PDT is a potentially effective treatment for condylomata acuminata.