Endoscopy: "A small section of the colonic wall is completely removed"

Interview with Prof. Karel Caca, Medical Director, Clinic for internal medicine, gastroenterology, haemato-oncology, diabetology and infectiology, Hospital Ludwigsburg

Eventually, all adults need to see a physician for colon cancer prevention. While the exam goes by quickly thanks to sedation, it sometimes leads to a follow-up procedure if a growth in the colon could not be removed with the endoscope and requires open surgery.


Photo: Karel Caca

Prof. Karel Caca; © Gottfried Stoppel

A new device that is mounted on the tip of conventional endoscopic devices can help in this case and save many patients from needing surgery. In the interview with MEDICA.de, Prof. Karel Caca talks about the goals pursued with this new endoscopic technique, its execution and testing.

Prof. Caca, you use the "full-thickness resection device" (FTRD) to remove adenomas in the bowel. What exactly is an adenoma?

Prof. Karel Caca: Adenomas are benign tumors that may become malignant and turn into colon cancer. Compared to cancer, there is still controlled cell growth with adenomas.

The development of the FTRD goes back to adenomas essentially occurring in two different types. What is behind all this?

Caca: One type of adenoma extends into the colon with a stem. This type can be conventionally removed during the endoscopy with a snare. On the other hand, there are flat adenomas that lie against the colonic wall, are hard to detach and sometimes need to even be surgically removed.

Ultimately, there are probably different mechanical factors that affect tissue growth that are behind both of these types. There are also biomolecular factors. Generally, flat adenomas develop from serrated adenomas in the colon on the right side of the body. These have a different kind of molecular biology than stalked polyps that primarily occur in the left side of the colon.

We also target the removal of polyps where the edge of a previous ablation is scarred and you are therefore no longer able to take them off and remove them via snare resection. In addition, flat polyps are sometimes located on the appendix vermiformis. In both cases, you needed to operate until now.

What does an intervention with the FTRD look like?

Caca: During this intervention, the entire colonic wall is completely removed in a small section, including the muscular layer and the adventitia, the outer adventitial tissue layer. During a snare polypectomy, the outer muscular layer is left to avoid the risk of any injury to the colonic wall. This is why so far only stalked polyps could be removed or flat polyps that were plumped up beforehand.

First, the colonic wall is pulled into the endoscopic cap. We fasten a clip to the base of this piece and remove it just above the clip with a snare. The clip ensures that the colonic wall remains closed.

How long does this wound take to heal or rather how long does the clip stay in the body?

Caca: So far, we are not 100 percent sure about this, because there are no studies on larger patient groups yet. However, the first cases show that after three months, between two-thirds and three-fourths of the clips detach on their own and are being excreted. This is a part of the natural healing process. We could otherwise also manually remove the clip, which is possible during the postoperative follow-up process.
Graphic: Removal of a colon polyp with a snare

Stalked adenoma can be removed with a snare, flat ones need to be removed during surgery. Tge "Full Thickness Resection Device" could change this; ©panthermedia.net/ Eraxion

This surgical technique is relatively new; what requirements do the attending physicians need to meet?

Caca: The physician needs to be very experienced in endoscopic surgery, in colonoscopies and the various types of polyp treatment. He or she should also have experience with the clip for the wound closure. This procedure is not just used in full-thickness colon wall resection, but also to stop bleeding for instance.

There is also a special one-day training course with a qualification exam for which participants receive a kind of “driver’s license” for the FTRD. We conduct these training sessions in Stuttgart together with the manufacturer Ovesco. The FTRD can only be used after completing the training.

What risks does this intervention entail?

Caca: As with any polypectomy, there is a risk of bleeding and perforation. However, this has not happened to us yet.

What did the previous device-testing look like?

Caca: Initially there was extensive animal testing of course. Recently we published the results of a first series with 25 patients. We were able to remove polyps in 24 of them. The pathologic examination finally revealed that the polyps were completely resected in 75 percent of the cases. In the remaining cases, the intervention can be repeated when the first wound has healed.

How do you plan to continue the testing?

Caca: We have started a nationwide multicenter study to keep testing the FTRD under controlled conditions even though the device is already for sale for training graduates. It is sold in Europe with CE certification. It is not being sold in the U.S, since it lacks FDA approval. However, we are still lacking a large database, which is why there are further studies. We know from the first patients that the application is safe and aside from one minor secondary hemorrhage, which was stopped endoscopically, there were no complications, but the treatment needs to be tested with a larger patient population.
Foto: Timo Roth; Copyright: B. Frommann

© B. Frommann

The interview was conducted by Timo Roth and translated from German by Elena O'Meara.