Click here to view next page of this article


Colon Cancer

Colonic obstruction devices. What about endolumenal therapy, such as laser photoablation therapy for colon cancer, colen cancer. This is an example of a proximal rectal tumor followed by laser photoablation therapy, a significant increase in lumen size.

The same downsides as with esophageal cancer, typically to achieve this effect requires multiple initial sessions and probably multiple follow-up sessions every couple of months or so. As far as stent therapy, the Schneider company has now made an entro-endo prosthesis which the indications have been achieved now for colonic stenting as well as for gastroduodenal stenting. What are the approved indications? The first one, for preoperative relief of obstruction. The goal here is to place the stent across the acute obstruction that may be presenting, hoping to decompress and then cleanse the colon which will then hopefully allow a single stage procedure.

The second indication is for palliative treatment. Is there a lot of data regarding this information? No, there certainly isnít. We are beyond the case report phase but certainly not anywhere near the controlled series approach. So basically we just have a couple of reports in the literature showing individual authors series at this point.

About 75 patients total. Successful placement averaged about 90% and these were lesions in the sigmoid colon, as well as the descending colon, and even transverse colon in a couple of patients. The delivery system is quite flexible. It can be maneuvered into the transverse colon if needed. The Italian group looked at patients on an attempt-to-treat basis, looking for "can the stent provide decompression and cleansing allowing for a single stage operation to occur?" and that was the case. That is, the stent allowed for that procedure to be carried out in almost two-thirds.

What about the second indication, for effective palliation? Again, very limited numbers here so take this certainly with a grain of salt, but effective palliation can be achieved with an expandable stent. The duration of therapy when stents were positioned averaged about 17 weeks. One patient went as long as 64 weeks. What are the problems? Certainly migration in the colon with colonic motility and especially when the stent is placed at an anatomical curve, the splenic flexure for example, those stents are much more likely to migrate. So the numbers are still quite high. From Dr. Baronís study of 25 patients, again the concern is migration in about 20%. Perforation occurred in four patients and that was primarily, they thought, due to the balloon dilation performed before the stent was placed. One interesting point, when they placed the stent, provided contrast material to check its site and to rule out perforation, and found an unrecognizable site of proximal obstruction in a couple of patients.

This is very flexible. The endoprothesis device, itís very flexible and the nice thing about that is it can be mounted on a very very small delivery system. Again, this has now been recently approved by the FDA. This is the delivery system with the typical stent mounted approach where the sheath is then withdrawn and the stent is then released. You can see the radiopaque markers which aid in fluoroscopic placement and guidance. Again, the retraction is a problem.

There are 10,000 cases per year in this country of esophageal cancer, and unfortunately most of those are un-resectable at time of presentation. The five-year survival was quite poor, and the life expectancy averages about six months in patients with un-resectable disease. Now as endoscopists, and physicians, our goal is to relive the most bothersome symptom for the patient, that is, the one that affects their quality of life most significantly, and that is dysphagia.

Whatís the best technique? Well, obviously one that can be accomplished quickly, conveniently for the patients where they are not tied to an endoscopy center repeatedly, the lowest cost, and the lowest morbidity and mortality. Palliative management, a number of guidelines; weíve got to confirm the diagnosis. The location, length, other characteristics of the tumor are important.

This is an example of an esophageal tumor, primarily exophytic as you can gauge by the roughened tissue within the midportion of the esophagus. This was a squamous cell malignancy. Now how should we manage this tumor? If you look at the relatively ancient literature, back in 1845 there was a Frenchman who used a decalcified elephant tusk.

So those are the first reported cases of so-called endoscopic intervention, but our therapy has actually evolved since then. In the modern era it is important to at least consider now radiation therapy. There are special protocols designed to shrink tumors rapidly over a short period of time, such as over ten fractions, but importantly, the response rate is quite variable especially for the responses for adenocarcinomas. The time to see tumors shrink is also quite variable. It can take as long as six weeks, even in the responders, before youíll get a significant effect - although the duration is usually around the time of five or six months where the benefit will be maintained.

Since the advent of the fiberoptic endoscope, a number of interventional technologies have evolved, and listed here in the order in which they appeared. Dilation therapy, simply using a bougie or a balloon dilator is simple, quite easy to perform, but as you would imagine, the benefit is quite short-lived and typically, repeated dilatations are necessary.

What about rigid prostheses? Those of you who have passed a couple of the Celestin type or other rigid type tubes probably get a visceral response just looking at this slide. Itís a fairly uncomfortable procedure both for the endoscopist as well as the patient, but basically this is where a rigid plastic tube is shoved through the distal tumor with the use of a pusher-tube device. Whatís the problem with this technique? Well, technically itís difficult to perform. These tubes are big.

Laser photoablation is ideal for an exophytic, non-circumferential type of tumor. Again that fleshy type of tumor. And with a couple of laser sessions you can see that the tumor melts away, and with further efforts you can see the laser being fired. This is again with the YAG laser. You can create a pretty significant lumen.

The new kids on the block are the self expanding metal stents. They were first modified for esophageal use about 1991. This is an example of the Schneider Wallstent in place. The advantage of this type of device - obviously those of you who place it are quite aware of this - but it can be mounted onto a delivery catheter where itís held in check with a sheath.