Controversial topics in abnormal cervical cytology: "see and treat"

Separation of normal and premalignant cervical epithelial cells using confocal light absorption and scattering spectroscopic microscopy ex vivo

Confocal light absorption and scattering spectroscopic (CLASS) microscopy can detect changes in biochemicals and the morphology of cells. It is therefore used to detect high-grade cervical squamous intraepithelial lesion (HSIL) cells in the diagnosis of premalignant cervical lesions. Forty cervical samples from women with abnormal Pap smear test results were collected, and twenty cases were diagnosed as HSIL; the rest were normal or low-grade cervical squamous intraepithelial lesion (LSIL). The enlarged and condensed nuclei of HSIL cells as viewed under CLASS microscopy were much brighter and bigger than those of non-HSIL cells. Cytological elastic scattered light data was then collected at wavelengths between 400 and 1000 nm. Between 600 nm to 800 nm, the relative elastic scattered light intensity of HSIL cells was higher than that of the non-HSIL. Relative intensity peaks occurred at 700 nm and 800 nm. CLASS sensitivity and specificity results for HSIL and non-HSIL compared to cytology diagnoses were 80% and 90%, respectively. This study demonstrated that CLASS microscopy could effectively detect cervical precancerous lesions. Further study will verify this conclusion before the method is used in clinic for early detection of cervical cancer.

Detection of cervical intraepithelial neoplasias and cancers in cervical tissue by in vivo light scattering

OBJECTIVE: To examine the utility of in vivo elastic light scattering measurements to identify cervical intraepithelial neoplasias (CIN) 2/3 and cancers in women undergoing colposcopy and to determine the effects of patient characteristics such as menstrual status on the elastic light scattering spectroscopic measurements. MATERIALS AND METHODS: A fiber optic probe was used to measure light transport in the cervical epithelium of patients undergoing colposcopy. Spectroscopic results from 151 patients were compared with histopathology of the measured and biopsied sites. A method of classifying the measured sites into two clinically relevant categories was developed and tested using five-fold cross-validation. RESULTS: Statistically significant effects by age at diagnosis, menopausal status, timing of the menstrual cycle, and oral contraceptive use were identified, and adjustments based upon these measurements were incorporated in the classification algorithm. A sensitivity of 77±5% and a specificity of 62±2% were obtained for separating CIN 2/3 and cancer from other pathologies and normal tissue. CONCLUSIONS: The effects of both menstrual status and age should be taken into account in the algorithm for classifying tissue sites based on elastic light scattering spectroscopy. When this is done, elastic light scattering spectroscopy shows good potential for real-time diagnosis of cervical tissue at colposcopy. Guiding biopsy location is one potential near-term clinical application area, while facilitating "see and treat" protocols is a longer term goal. Improvements in accuracy are essential.

In vivo light scattering for the detection of cancerous and precancerous lesions of the cervix

A noninvasive optical diagnostic system for detection of cancerous and precancerous lesions of the cervix was evaluated in vivo. The optical system included a fiber-optic probe designed to measure polarized and unpolarized light transport properties of a small volume of tissue. An algorithm for diagnosing tissue based on the optical measurements was developed that used four optical properties, three of which were related to light scattering properties and the fourth of which was related to hemoglobin concentration. A sensitivity of ~77% and specificities in the mid 60% range were obtained for separating high grade squamous intraepithelial lesions and cancer from other pathologies and normal tissue. The use of different cross-validation methods in algorithm development is analyzed, and the relative difficulties of diagnosing certain pathologies are assessed. Furthermore, the robustness of the optical system for use by different doctors and to changes in fiber-optic probe are also assessed, and potential improvements in the optical system are discussed.

In vivo light scattering measurements for detection of precancerous conditions of the cervix

OBJECTIVE

To examine the utility of in vivo elastic light scattering measurements to diagnose high grade squamous interepithelial lesions (HSIL) of the cervix.

METHODS

A newly developed fiber optic probe was used to measure light transport in the cervical epithelium of 36 patients undergoing standard colposcopy. Both unpolarized and polarized light transport were measured in the visible and near-infrared. Spectroscopic results of 29 patients were compared with histopathology of the measured sites using ROC curves, MANOVA and logistic regression.

RESULTS

Three spectroscopic parameters are statistically different for HSIL compared with low-grade lesions and normal tissue. When these three spectroscopic parameters are combined, retrospective sensitivities and specificities for HSIL versus non-HSIL are 100% and 80%, respectively.

CONCLUSIONS

Reflectance measurements of elastically scattered light show promise as a non-invasive, real-time method to discriminate HSIL from other abnormalities and normal tissue. These results compare favorably with those obtained by fluorescence alone and by fluorescence combined with light scattering.