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Special problems associated with surgical trials in inflammatory bowel disease
RS McLeod
It
is well accepted that the randomized controlled trial
(RCT) is the best design for determining treatment effectiveness.
Despite this, the surgical literature, particularly
in the area of inflammatory bowel disease, is replete
with case series while there is a paucity of RCTs assessing
surgical interventions. There certainly is no lack of
questions to be answered and there is a lack of consensus
on many issues. Why then are there so few RCTs? Unfortunately,
it appears that surgeons in general are more accepting
of evidence from case series. However, it also appears
that there are certain issues that are unique to, or
at least occur more frequently in, clinical trials assessing
surgical interventions. The issues of special concern
in surgical trials can broadly be categorized as methodological
and feasibility issues. Methodological issues include
difficulties in standardization of the procedure, deciding
on the timing of the trial and prevention of bias when
blinding may be difficult or impossible. All these are
challenges, but do not preclude the performance of RCTs.
On the other hand, feasibility issues may pose more
of a challenge. Patients may refuse entry, particularly
if they view the two treatments as `unequal' (eg, medical
versus surgical therapy) and irreversible (as they usually
are in surgery). Patient accrual may be difficult given
the variable patterns of disease and indications for
surgery. Finally, unlike medical therapies which are
controlled by regulating agencies, surgical procedures
can simply be performed and there may be little incentive,
and even some disincentives, for the surgeon to participate
in a trial. Despite these difficulties, better evaluation
of surgical therapies is required. Where possible, RCTs
should be performed, but in situations where this is
not possible other trial designs must be employed that
may lack some of the rigour of an RCT but that are more
rigorous than the uncontrolled case series.
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