Operational Issue Relating to Endo-Microscopy: Some Early Speculation

In a previous note (see: Progress in Diagnoses with Endo-Microscopy), I discuss some of the evolving science and technology underlying endo-microscopy. Using this technique, a probe is inserted into suspicious lesions discovered during colonoscopy. This probe functions as a confocal microscope and provides a detailed examination of the lesion at the cellular level. After reading this note, Bev MD posted the following comment:

As a pathologist, I would have a few questions about the sensitivity/specificity of this technique. How would it label cells that we consider "dysplastic' for instance? What would be its false negative rate, risking nonremoval of a cancerous polyp that has invaded by the time of a re-exam? Given the relative ease of resecting most polyps, I can't see much benefit except for saving the pathologist's bill, given that the endoscopist would now charge more using this technique, plus a polyp excision charge for ones deemed "malignant". Or am I missing something?

All good questions but perhaps somewhat premature given that this technology is still in the research stage and therefore has not entered into standard clinical practice. However and as I speculated in my note, the major potential and obvious advantage of endo-microscopy is its  ability to determine real-time whether borderline lesions are benign or malignant. It would then be possible to resect malignant and dysplastic lesions during the procedure or immediately afterward with a surgical procedure.

I can't help drawing an analogy between this new approach and fine-needle aspiration (FNA) of "lumps and bumps" in the breast, thyroid, and lung lesions. The cells aspirated from the lesion are immediately examined by a cytopathologist and the patient is spared a traumatic surgical procedure for purposes of diagnosis. In the case of endoscopy, recent news (see: Flat Colon Lesions Identified And Removed Using Colonoscopy) suggests that the diagnosis of gross lesions in the colon may be more challenging than previously thought. Here is an excerpt from the article:

A study released this week from researchers at the Veterans Affairs Palo Alto Healthcare System in California shows that non-polypoid colorectal neoplasms or flat colon lesions, are more common in Americans than previously thought and may have a greater association with cancer compared to polypoid neoplasms or the more commonly diagnosed colorectal polyp.

So where does all of this leave us, admittedly at an early stage in the development of the endo-microscopy? Here are some of my early ideas:

• Research on endo-microscopy will undoubtedly continue, perhaps resulting in an extension of the diagnostic capabilities of colonoscopy and with the added ability to determine, perhaps with certainty, the diagnosis of colonic lesions real-time.
• It is quite possible, following the example of FNA, that the microscopic diagnosis during endoscopy will be turfed to pathologists who will participate in the procedure. Given that the majority of colonoscopies reveal no suspicious lesions at all, it could make perfect sense for pathologists to provide such support.
• Pathologists are now commonly joining gastroenterology groups to diagnose the tissue samples obtained during various procedures such as endoscopy. If endo-microcopy eventually takes hold, the technology may act as an incentive for more gastroenterology groups to recruit their own pathologists.

Comments

[Joy Mammen]

Two comments:
1. If diagnosed during the colonocsopy and the polypectomy was done on the grounds of malignancy, or suspicion thereof, would it preclude the "final diagnosis" procedure ie stained tissue sections from paraffinized blocks. Our current concepts of pathological diagnosis rests of visualization of the pathological entity on identified tissue sections, which could potentially be available for second review or further testing. Whereas with endomicroscopy, there would only be images. Needs a paradigm shift.
2. Imagine a scenario where the pathologist is also informed of the colonocsopy procedure (like a frozen section) and dials in /logs into the procedure through the internet and sees the real time images to help the gastro-eneterologist.