Quantitative spectroscopy for detection of cervical dysplasia

Abstract

The current clinical standard for cervical cancer diagnosis is colposcopy, a procedure that involves visual inspection and biopsy of at-risk tissue, followed by histopathology. The major objective of colposcopy is detection of high-grade squamous intraepithelial lesions (HSIL), which are precancerous lesions with high risk of progression. Colposcopy, even when conducted by experts, is subject to significant diagnostic variability. The aim of the work presented in this thesis was to develop a non-invasive clinical tool for detection of cervical HSIL and for guiding the biopsy during colposcopy. Previously we have developed a contact-probe portable instrument for tissue reflectance and fluorescence collection, and spectral analysis models to extract and quantify biochemical and structural features of tissue to provide disease state assessment. In this thesis we further refine the instrumentation and spectral analysis models and conduct the clinical in vivo studies. The clinical in-vivo study showed cervical anatomy was a confounder to diagnostic algorithms that treat cervix as spectroscopically uniform. We used complex instrumentation to comprehensively study cervical tissue and found that scattering alone was sufficient to identify HSIL. We developed an accurate algorithm based on tissue scattering for detection of HSIL in the cervical transformation zone, an area where vast majority of cervical lesions arise. We further successfully extended our point-probe technique into the imaging mode, to provide the wide-area surveillance capability.

(cont.) The ongoing imaging clinical in-vivo feasibility study demonstrates spectroscopic contrast between cervical HSIL and non-HSIL tissue and is consistent with findings of the contact-probe study. The future steps include diagnostic accuracy assessment of the imaging technique, and if proven successful, a clinical study to evaluate the performance of spectroscopy-guided biopsy.