Reviewer’s report
Reviewer Hirotoshi Ishiwatari
(1) Thank you for good advice. This article is retrospective, small cases, and single
center study. This is a most important weak point about this study. We couldn’t design
prospective study. But according to statistical analysis, clinical features, pre-endoscopic
laboratory data, preoperative endoscopic treatment, and other many factors were not
significant different between both groups. I didn’t use the propensity score-matching
method.
(2) Thanks you for good advice for my article. If the distance from the stricture to the
sphincter of Oddi was more than 2 cm, we selected mainly conventional stent from
December 2006 to June 2009. And we selected mainly ‘inside stent’ from June 2009.
(3) Thanks you for good advice for my article. Previous study evaluated long patency
periods of plastic stent placement lasting until the patient’s death. Recently, some
systemic chemotherapy or radiotherapy for the patients with biliary tract cancer
prolonged progression free survival and overall survival. So, we should perform some
chemotherapy or radiotherapy for the patients with initially unresectable biliary tract
cancer. We might convert the surgical resection after these treatments in some cases.
Biliary tract infection is the most severe adverse events for the patients with systemic
chemotherapy of biliary tract cancer. We might prevent this risk to be continuing safety
systemic chemotherapy. The aim of this study was inside stent could prolong patency
period until surgical resection with or without chemotherapy.
(4) Thanks you for revised to my article. I described about conventional stent, a 7-Fr
Amsterdam-type polyethylene stent or 8.5-Fr or 10-Fr Tannenbaum-type Teflon stent
(Cook Medical, Bloomington, Minnesota, USA). We didn’t prepare the stent of same
type for each size in our institution. And also if we only analyzed single stent, this study
would be too small to analyze.
(5) Thanks you for revised my article. EST was a risk factor for reflux cholangitis but
we experienced the severe acute pancreatitis large caliber stents placement without EST.
We only performed this procedure for large caliber stent placement. This procedure
didn’t perform for the placement of small caliber stents (7Fr or 8.5Fr).
(6) Thanks you for good advices. Percutaneous biliary drainage was very useful and
promising treatment for biliary stricture. But our aim of this study was to evaluate the
risk of cholangitis by preoperative endoscopic treatment, especially difference of inside
stent or conventional stent. So, we excluded percutaneous treatment cases before
surgical resection.
(7) ICC was other entity according to pathological and clinical diagnosis, especially in
Japanese criteria. And, many ICC was expansive growth in liver parenchyma and the
cases of surgical resection after preoperative biliary drainage were very small in our
institution. So, we excluded ICC cases.
(8) Five cases (15.6%) in conventional stent group and four cases (16%) in inside
stent cases were initially treated by acute cholangitis and ENBD tube was placed. And
we defined the decompression period was the days from endoscopic treatment to normal
bilirubin level. (I described this definition in evaluation section.)
We initially placed ENBD tube especially infection cases. We placed conventional or
inside stent for obstructive jaundice without infection cases. After we controlled
infection by ENBD tube, plastic stent was placed by same strategy. In our study,
cholangitis before initial endoscopic treatment were not significantly difference about
stent patency periods.
(9)
Thanks you for good advice. In this study, there was no case of portal
embolization before surgical resection.
(10) Thanks you for good advice. Stent occlusion was defined as recurrence of
jaundice and/or evidence of dilated biliary systems detected by some imaging
modalities.
(11) Thanks you good advice. In our study, primary lesions of many cases were
inferior or middle bile duct. Superior or common bile duct cases were small in this
study.
(12) Thank you good advice. We changed this part from severe to ‘liver abscess that
we performed percutaneous drainage’.
Reviewer’s report
Reviewer Jong Ho Moon
(1) Thanks you for good comment. Liver resections in jaundiced patients are associated
with high morbidity and mortality rate. On the other hand, preoperative biliary drainage
may associate with an increased incidence of postoperative morbidity and hospital stay.
There is still controversy with regard to whether preoperative biliary drainage is
essentially needed for jaundiced patients with biliary tract cancer. This article is
challenging study to prevent reflux cholangitis by performing endoscopic treatment for
the preoperative management of cases with biliary tract cancer.
(2) Thanks you for good comment. We decided the indication of preoperative
chemotherapy or chemoradiotherapy according to resectability.
(3) Thanks you for good comment. We usually used ENBD tube for the obstructive
jaundice with infection cases. Other cases were placed conventional or inside stent.
(4) Thanks you for good comment. Mainly the stent selection was relied on the each
endoscopists.
(5) Thanks you for good comment. The length of nylon thread about 2cm from the
orifice of papilla.
(6) Thanks you for good comment. We defined the stent migration that proximal
migration was ‘located above the original stricture site’ and distal migration was
‘located below the original stricture site or no longer visible either endoscopically or
radiographically. We defined the acute cholangitis as elevated levels of liver and/or
biliary enzymes with the onset of fever (>38C).
(7) EST was a risk factor for reflux cholangitis but we experienced the severe acute
pancreatitis large caliber stents (10Fr) placement without EST. So, we performed minor
sphincterotomy to place large caliber stents. This procedure was not used for the
placement of small caliber stents (7Fr or 8.5Fr). We evaluated the stent patency period
according to stent diameter. But, there was no significantly difference according to stent
diameter in this study. I added the data in the Table 7. According to past report, stent
diameter was correlated with stent patency period. We performed EST for every cases
of 10Fr stent placement, this factor may be influence the patency period shorten.
(8) Thanks you for good advice. I deleted this part from the result section.
(9) Thanks you for good advice. I added the figure of hilar stricture case and lower bile
duct stricture case.
(10) Thanks you for good advice. In many cases with inoperative malignant biliary
strictures, a self-expanding metallic stent was selected to enable a longer patency period
than that for a plastic stent. However, preoperative metallic stent placement created an
obstacle for subsequent surgical resection. Particularly in cases with hilar bile duct
cancer, the use of a metallic stent is very difficult and risky for subsequent resection
Reviewer’s report
Reviewer Toshio Tsuyuguchi
Major
#1. Thank you for good advice. I analyzed the stent diameter data for stent obstruction.
Stent diameter (7 or 8.5 Fr) was not significant preventative factors associated with
stent obstruction in this study. Additional data was described in the Table 7.
#2.Thank you for good advice. This study was retrospective study, I agreed your
comment. But, we enrolled all cases of malignant biliary stiructures that the distance
from the stricture to the sphincter of Oddi was more than 2 cm and excluded
percutaneous treatment cases and/or pancreas, ampulla and intra-hepatic cancer. If the
distance from the stricture to the sphincter of Oddi was more than 2 cm, we selected
mainly conventional stent from December 2006 to June 2009. And we selected mainly
‘inside stent’ from June 2009.
Some cases didn’t receive preoperative chemotherapy and surgical resection didn’t
perform long period because of equivocal pathological diagnosis or patient’s rejection.
Selection bias was included in this study. I described this point in discussion section.
Minor
#3. Thanks you for good advice. Your comment is very important. We must be careful
treatment to remove inside stent, because distal end and proximal flap of inside stents
wound injury biliary epithelial walls.
#4. Thank you for advice, I changed ‘sphincter of Odd’ to ‘sphincter of Oddi’.
#5. I changed some English correction.