Dynamic spectral imaging: improving colposcopy.

Purpose: Colposcopy occupies a key role in the prevention of cervical cancer by identifying preinvasive or invasive lesions. However, colposcopy is subjective and is responsible for 52% of screening failures. Dynamic spectral imaging (DSI) is based on the objective, quantitative assessment of the acetowhitening effect. This study compared DSI with colposcopy.

Experimental Design: Women referred for colposcopy were examined simultaneously with colposcopy and DSI using a precommercial DySIS model (FPC-03) in an international, multicenter trial. The colposcopy impression and DySIS values were compared with consensus histology reports of biopsies. Subjects were recruited to a training group and subsequently to a test group. Measures were taken to avoid verification bias.

Results: The training and test groups comprised 82 and 308 eligible women, respectively. A cutoff value to identify high-grade disease was selected from the results of the training group and data from previous work. Receiver operator curve analysis of the test data showed an area under the curve of 0.844. DySIS detected 62.9% more high-grade cases than colposcopy (57 versus 35, P=0.0001). DySIS exceeded end points approved by the Food and Drug Administration for similar studies, with increments in the true positive rate of 22/308 (7.1%; lower 95% CL, 4.5% versus 2%) and in the false positive rate of 32/308 (10.4%; upper 95% CL, 14.7% versus 15%).

Conclusions: DySIS is more sensitive than colposcopy in detecting high-grade lesions and can provide improved guidance for biopsy. The results are obtained in a user-independent fashion, making it suitable for use by nursing personnel.