Esophageal HILZO Covered self-expandable metal stent for palliation of malignant dysphagia: A Safety and Feasibility Study

The majority of esophageal cancer patients have unresectable disease at
presentation. Even after curative therapy, about 20% of patients develop
dysphagia from recurrent strictures. Dysphagia is the predominant symptom in
70% of esophageal cancer. Complications include high risk of aspiration and
reduced patency of the orogastric pathway, which lead to a profound reduction
in quality of life.
Therefore, palliative therapy has been, and will continue to remain, an
important part of the management of esophageal malignancy. The primary goal of
palliative treatment in patients with esophageal cancer is to achieve adequate
improvement in this dysphagia and therefore quality of life, with a reduced
need for additional interventions.
Although optimal intervention for treatment of dysphagia has yet to be
established, self-expandable metal stents (SEMS) have been largely superseded
by other interventions since their introduction in the early 1990s. Esophageal
stents have continued to evolve and are now the palliative modality of choice
due to their ability to provide instant, long-lasting relief from dysphagia
with minimal morbidity and negligible mortality.1

1st Generation SEMS: Uncovered SEMs
The first commercially produced self-expandable metal stent was the Wallstent,
made of stainless steel. Ultraflex stent, developed by Boston Scientific
(Natick, MA, USA) was the first stent to be made of nitinol, a shape-retaining
nickel and titanium alloy. Since then, nitinol is most popular stent wire
material.

2nd Generation SEMS: Covered SEMS
To prevent tumor ingrowth into stent, fully or partially covered stent is
introduced in 1990 . Covered material is various: Polyurethane, silicone and
PTFE.

3rd Generation SEMs: Retrievable SEMS
A retrievable fully covered SEMS is introduced in 1997. Drawstrings were
attached to stent to help remove or reposition the stent.

4th Generation: Self-explandable Plastic Stent
Polyflex is the first Self-expanding plastic stents (SEPS) characterized
removability.
HILZO Esophageal covered stent system belongs to 2nd and 3rd generation stents
which have been used more than 20 years and share the similar characteristics
with other 2nd and 3rd generation stents

The HILZO Esophageal covered stent has been evaluated for palliation of
malignant dysphagia and has been approved with a Conformité Européenne (CE)
certificate for the maintenance of esophageal lumen patency in malignant
dysphagia.
Since there is limited data on the effectiveness in the clinical context, the
aim of this study is to evaluate the safety and efficacy of the TTS placement
of HILZO Esophageal covered stent.

In this study we not only investigate the safety and feasibility of the stent
alone but also the method of implantation. Due to a new technique of placing
the stent with a through-the-scope (TTS) method, the HILZO Esophageal covered
stent has several advantages:
o Less invasive procedure for implanting the stent, i.e. no guide-wire
insertion required for placement, so the procedure is less demanding on the
patient.
o No fluoroscopy is required to ensure correct stent placement
o Higher cost-effectiveness due to reduction of costs of stent placement, due
to less material (guide-wire), no special endoscopic and radiologic staff and
equipment is required in this procedure.

In the future, when the TTS placement is found to be a safe and feasible method
in clinical practice, we will design a subsequent study that compared the TTS
stent placement with guide-wire placement to investigate the effect on patient
satisfaction and cost-effectiveness.

The main objective of this study is to evaluate the safety and efficacy of
placement of the esophageal HILZO Covered stent with the TTS method in patients
with non-operable malignant obstruction of the esophagus or esophagogastric
junction, extrinsic malignant compression, or recurrent malignant dysphagia
after esophagectomy.

Other (secondary) objects are to assess the effect of the stent on the presence
of hyperplastic reaction after implantation, the functional complications and
survival.

A non-randomized prospective clinical study in a single center (Radboudumc), to
evaluate the safety and efficacy of endoscopic TTS placement of the esopageal
HILZO Covered stent in patients with non-operable malignant obstruction of the
esophagus or esophagogastric junction, extrinsic malignant compression, or
recurrent malignant dysphagia after esophagectomy.

After stent placement patients will be evaluated with a telephone interview 14
days later and at 4-week intervals until death.

The HILZO* Esophageal Stent system (BCM Co. Ltd.) is intended for maintaining
esophageal luminal patency in esophageal stricture. It is comprised of two
components; an implantable metallic stent and a flexible introducer system.
After the operation, the stent remains at the intended location, within the
patient while the introducer system is removed.

Delivery system: through-the-scope (TTS)
Delivery system is for delivery and release the stent to intended site. The
stent is mounted on an inner catheter and is constrained by an outer tube. The
outer tube is pulled back by immobilizing the metal tube holder in one hand,
grasping the handle with the other hand, and gently sliding the handle along
the metal tube (2nd inner catheter) towards the metal tube holder. Retraction
of the outer sheath releases the stent. HILZO Stent system has two different
delivery systems by its approach. TTS delivery system is 180cm.

Participation in the study does not cause any additional charge to patients.
The stent implantation and follow-up are not different from the usual in
standard clinical practice.

The main advantage of TTS stent placement is that it is less complicated and
invasive, i.e. no guide-wire placement is required. Moreover, another advantage
is that no fluoroscopy is required to verify correct stent placement. The
absence of required fluoroscopy in this procedure on the endoscopy department
will reduce the costs of stent placement in malignant dysphagia, i.e. no
special endoscopic and radiologic staff and equipment is required in this
procedure.

In the future, when the TTS placement is found to be a safe and feasible method
in clinical practice, we will design a subsequent study that compared the TTS
stent placement with guide-wire placement to investigate the effect on patient
satisfaction and cost-effectiveness.

The risk classification is determined as negligible based on the guideline of
the *Nederlandse Federatie van Universitair Medische Centra*. The risks
associated with the participation in the study are similar to the risks of
treatment with any esophageal stent, and not different from the complications
arising from the use of other expandable stent; migration, bleeding,
perforation and development of hyperplasia/ granulation tissue.