A new light based test that detects early signs of cervical cancer may be a better diagnostic tool than a pap smear, according to preliminary findings from a multi-site Food and Drug Administration (FDA) pivotal clinical trial. The study of more than 1,900 women looked at Guided Therapeutics‘ LightTouch system, a device that uses optical probe to shine light at different wavelengths and to detect alterations in fluorescence spectra coming back from the dysplastic /cancerous growth.
From the press release:
Since the pivotal trial began, more than 1,900 women were tested to demonstrate the technology’s safety and efficacy in detecting cervical disease, including an arm of the study that assessed effectiveness of an investigational commercial version of the device and single-use disposable.
The study protocol indicated that all subjects were referred after undergoing a Pap test, or had some other risk factor that fulfilled the referral criteria of the study. Each subject was tested with the LightTouch investigational device and underwent an additional Pap test, colposcopic exam and biopsy. Two generations of the investigational LightTouch were used in the trial.
Preliminary results from the study showed that the LightTouch performed better than the Pap test. The investigational commercial version of the LightTouch detected approximately 46 percent more cervical disease than the Pap test – a statistically significant improvement.
Here’s more about the technology from the manufacturer:
The device system (Guided Therapeutics, Inc. Norcross, GA, USA) used in the study is a nonsignificant risk device by FDA standards that noninvasively and automatically scans the ectocervix and distal endocervix for disease related changes in fluorescence and reflectance spectra.
Alterations in fluorescence spectra are indicative of metabolic changes associated with neoplasia, while alterations in reflectance and scattering are indicative of structural changes associated with neoplasia, such as epithelial thickening, nuclear size, nuclear content and angiogenesis.
A plurality of equally spaced points over a one-inch diameter area of the cervix was automatically scanned during a four-minute period using a filtered xenon arc lamp as an illumination source.
For cervical tissue reflectance measurements, broadband spectral output ranging from about 350 to 900nm was automatically applied under software control to the cervix using the same xenon arc lamp. The resultant reflectance spectral output from the cervical tissue was imaged onto the CCD camera and stored for processing
For cervical tissue fluorescence measurements, light from the arc lamp was band pass filtered to limit exposure
of the cervix to bands within the 300 to 500 nm range. These spectral bands are known to excite fluorophores associated with neoplastic processes as described above. Each of the fluorescence wavelengths were applied automatically under software control in a predetermined order and scan pattern. The resultant fluorescent spectral output of the cervical tissue was imaged onto a charge coupled device (CCD) camera and stored for processing and analysis.
The system consists of two main physical components, the hand-held unit and the base unit. The handheld unit is
connected to the base unit via fiberoptic cables for transmission of light to and from the base unit, which contains the xenon arc lamp, optical processing elements (e.g., filters and lenses) and the CCD camera on a rolling cart (CNDS Device).
The other major component of the CNDS is a computer for control and data processing. This includes the capability for a diagnostic algorithm based on spectroscopic information measured from the cervix, calibration data and other patient data, such as Pap results or patient demographic data.
Press release: Guided Therapeutics, Inc. Reports Preliminary Findings from FDA Pivotal Clinical Trial (PDF)
Device page: LightTouch…
Poster about the system (.pdf) from Georgia Life Sciences Summit 2006…
Bottom image: Cervical maps with biopsy sites marked X.