10.1055/a-1006-2658We read with great interest the recently published study on comparing multiple stents
and single stent insertion for pain relief in chronic pancreatitis (CP) [1]. The author concluded that treatment with a single stent was associated with better
clinical outcome compared to treatment with exclusively two stents during the stenting
period. However, we found some flaws in the study design that might have made the
conclusion inaccurate.
First, there may be patient selection bias in terms of study design which caused the
inconsistence of severity of distal stricture and painful episodes for patients underwent
single stent or two stents insertion. Patients were retrospectively reviewed and divided
into three groups according to number of stents insertion during the stenting period.
Degree of distal stricture, frequency and number of painful episodes were not exhibited
or compared among the three groups. Indeed, patients who were treated with two stents
probably had more severe distal strictures or more severe and painful episodes before
the stent insertion. Otherwise, why were these patients not treated with a single
stent? As suggested in both the 2012 and 2018 European Society of Gastrointestinal
Endoscopy (ESGE) guidelines for CP, painful dominant main pancreatic duct strictures
should be treated with a single plastic stent and multiple side-by-side plastic stents
can be considered when symptomatic main pancreatic stricture persists for more than
1 year after placement of the initial single plastic stent [2]. Therefore, patient selection bias caused the inconsistent distal strictures and
painful episodes between patients treated exclusively with two stents and those treated
with single stent, which probably led to bias in treatment outcome.
Second, there is a defect in the definition of clinical endoscopic treatment outcome.
Patients in the study had continuous or recurrent pain with at least three painful
episodes per year before endoscopic treatment. However, the authors did not provide
detailed information on painful episodes. Endoscopic treatment outcome was simply
defined according to Izbicki score (IS) at the end of the stenting period, with successful
endoscopic treatment being defined as IS ≤ 10 at the end of the stenting period. Besides
IS, frequency and number of painful episodes also greatly affect patients and are
critical indicators of quality of life, but they were ignored when evaluating treatment
outcome. When defining the primary objective, outcome of endoscopic treatment, frequency
and number of painful episodes should be considered.
In addition, the efficacy and safety of multiple plastic stents for refractory main
pancreatic stricture in CP has been underscored in the 2012 and 2018 ESGE guidelines
and several prospective studies [2]
[3]
[4]
[5]. Use of multiple pancreatic stents has proven to be promising in achieving persistent
stricture dilation on long-term follow-up in the setting of severe CP. Thus, the author
should conduct rigorous studies to provide higher-quality evidence about the current
conclusion or doubt may be cast upon it.
Conclusion
In conclusion, the design and definition of the primary objective in the current study
could have been improved. Moreover, more stringent research should be done to verify
the author’s conclusion.
