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Optical Techniques More Efficient Than Conventional Histopathology for Identifying Pre-Cancerous Polyps

NEW YORK -- November 10, 2009 -- Optical diagnosis is a reliable method of correctly diagnosing small colorectal polyps during routine colonoscopy and could be a more efficient and cost effective alternative to conventional histopathology. As such, optical diagnosis could replace formal histopathology for the diagnosis and management of most small polyps in routine clinical practice, finds an article published online first in The Lancet Oncology.

New optical technologies that use white-light colonoscopy (WLC), non-magnifying narrow-band imaging (NBI), and chromoendoscopy have enhanced the ability to diagnose and manage small polyps seen at routine colonoscopy dispensing with the need for formal histopathology -- which is time consuming, resource intensive, and results in delays in giving patients advice on future cancer risk and screening intervals.

It has been suggested that these optical technologies could make colonoscopy more efficient and cost effective.

To confirm the efficiency, safety, and clinical benefit of these simple and widely available optical techniques, Ana Ignjatovic, St. Mark's Hospital and Imperial College London, London, United Kingdom, and colleagues compared the diagnosis of 363 small colorectal polyps (<10mm) in 130 patients.

The polyps were evaluated by 4 colonoscopists with different levels of experience, using both optical diagnosis (WLC, NBI, and chromoendoscopy) and histopathology. The authors also assessed the accuracy of optical diagnosis at predicting a patient's future cancer risk and advice on screening intervals.

Overall, optical diagnosis accurately identified up to 93% of small colorectal polyps (186 of 198 precancerous adenomas and 55 of 62 hyperplastic polyps), similar to the overall diagnostic accuracy of standard histopathology. Expert colonoscopists had an accuracy of 95% for optical diagnosis and non-expert colonoscopists 87%.

In addition, optical diagnosis enabled 82 of the 130 patients to be given a follow-up colonoscopy date immediately after the procedure, providing a savings cost in follow-up clinical appointments.

Findings also showed that advice on screening intervals was the same after histopathology and optical diagnosis for 78 of 82 patients (95%).

The authors estimate that replacing histopathology with optical diagnosis in routine clinical practice would have resulted in an overall saving of 77% for the patients in this study.

"We have shown that optical diagnosis, mainly using white light and non-magnified NBI, is accurate for characterisation of polyps smaller than 10 mm...and seems acceptable across a range of experience," the authors wrote.

"The short learning curve for NBI…supports early adoption, even outside academic centres. As NBI equipment and experience becomes widespread, optical diagnosis for small colonic polyps could become acceptable standard of care in routine non-academic clinical practice."

SOURCE: The Lancet Oncology

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