Visit 1 for all participants will consist of going over the Informed Consent form and
talking with the patient about the study. If the patient agrees to participate, he/she
will be asked to sign the form, and a copy will be given to him/her for his/her records.
This will be conducted during the day of the endoscopic procedure before the participant
is under anesthesia. The treatment provided will be standard-of-care that is offered to
patients with pancreatic cyst lesions (PCL) interested in undergoing EUS-guided ethanol
ablation.
An MRI of the abdomen will be obtained as baseline measure to determine the size of the
pancreatic cyst and confirm diagnosis.
Prior to undertaking any ablation, the cyst fluid will be sampled at a prior EUS session
to check for mucin, viscosity, carcinoembryonic antigen (CEA) (>200U/L=mucinous cyst),
amylase and if required molecular marker analysis. Once a PCL is determined to have a
malignant potential the patient will be selected for EUS-guided ablation. All patients
will receive a dose of intravenous ciprofloxacin 500mg 30 minutes prior to the ablation.
These evaluation and treatment measures are standard-of-care for any patient with
pancreatic cyst lesion undergoing EUS-guided ethanol ablation.
Procedural Technique: All procedures will be undertaken using a curvilinear
echoendoscope. Once a cyst is identified for ablation it will be punctured using a 22G
needle. After subtotal evacuation of the cyst, injection is performed with a volume of
alcohol that is equal to the quantity aspirated, and the cyst will be lavaged for 3 to 5
minutes, alternatively filling and emptying the cavity. The injected ethanol will then be
evacuated at the end of lavage, leaving just enough fluid to outline the cavity. A second
ablative agent such as paclitaxel is then injected and left in the cyst cavity; the
volume injected should not exceed the volume of aspirated fluid. The needle tip must be
carefully maintained within the cyst to avoid parenchymal injury or cyst wall leak. At
the completion of the procedure, the needle will be removed from the cyst cavity. When a
cyst is not restored to its original size during ethanol injection, vigorous lavage and
aspiration must be avoided because of probable communication with the main pancreatic
duct.
In patients with multi-loculated cysts, a single injection may not provide sufficient
drug delivery to all locules within a cyst. It is important to determine the optimal
angle at which the needle can be introduced into the maximum number of targeted locules.
When all punctured locules cannot be visualized on endosonographic image, needle passage
across a septation may be indicated. The simultaneous collapse of locules across the
septum during cyst fluid evacuation and spread of echogenic bubbles across the septation
during injection of ablative agents are indication of good distribution of the ablative
agent into the locules. This is important as a missed locule may result in cyst regrowth
and treatment failure. While additional needle passes through different angles may
increase the effectiveness of cyst ablation it will also increase the incidence of
adverse events. Therefore a second needle puncture may be considered only when the risk
of adverse events appears low.
The relative effectiveness of the procedure is related to the degree of contact between
the ablative agent and the cyst epithelium. However, it is important to maintain the
needle in the visual plane and within the cyst cavity during the entire procedure. All
techniques described above are standard-of-care treatment measures offered to patients
undergoing EUS-guided ethanol ablation of pancreatic cysts.
Ablative agents:
Ethanol: concentration of 80-99% may be used.
Paclitaxel: Because of the high viscosity of its cosolvent (castor oil) the
paclitaxel solution must be diluted 1:1 in 0.9% normal saline to yield a final dose
concentration of 3mg/mL. However, if the agent is available in a less viscous format
(polymeric micelle) it can be used without dilution (a dose concentration of
6mg/mL).
Follow-up:
Patients will be admitted overnight for observation and kept nil by mouth. A
complete blood count and serum amylase level will be checked the next day and
patients will be discharged home if clinically well, with no evidence of
pancreatitis or other adverse events and can tolerate a low fat diet. Patients will
be prescribed oral ciprofloxacin 500 mg to be taken twice a day for three days. This
will be standard-of-care follow-up.
A CT of the abdomen will be obtained at 3 months to assess treatment response. If
there is no change in size of the cyst, further CT scans will be scheduled at
3-month intervals with another attempt at EUS-guided cyst ablation. If there is
complete or partial cyst resolution, follow-up CT scans will be obtained at 6-month
intervals. If complete resolution is documented on two CT scans, then the patient
will be scheduled for annual CT scans. This will be standard-of-care follow-up. 3.
Patients with persistent or only partial cyst resolution despite two ablative
treatment sessions will be referred to a pancreatic surgeon for consultation. If the
patients are high-risk surgical candidates, surveillance by EUS and cross-sectional
imaging will be continued per International Society of Pancreatology guidelines.
This will be standard-of-care follow-up. 4. Definitions: Using multi-detector CT
scans and specialized software the original volume (OV) of the cyst will be
calculated by the radiologist. Complete resolution will be defined as the cyst being
nonvisible or less than 5% of the OV on follow-up CT; Partial resolution of the cyst
will be defined as decrease in size by 5-25% of the OV and the cyst will be defined
as Persistent if > 25% the OV.
