形成外科医のアメリカ留学計画

RCT (Randomized controlled trial)は
EBM研究のなかでも1番エビデンスレベルの高い研究手法だ。

例えば、
新規薬剤"ミシガンシロップ"の有効性を
RCTにより調査すると仮定する。

RCTとは、
被験者を無作為（random）に、
■A群：ミシガンシロップを内服する群
■B群：プラセボを内服する群
に割り付けて、後のアウトカムを比較検討する試験のこと。


（http://library.downstate.edu/EBM2/2200.htm より）

データの偏り（bias）を最小限にできるため
最もエビデンスレベルの高い研究手法として認識されている。
両群に生じたアウトカムの違いが
ミシガンシロップによる可能性が極めて高いことになる。

このRCTは一見理想的であるが
外科的手術において導入するときに多くの問題が生じる。
下記に主な理由をまとめた。

A. Difficult to obtain uniformity in surgical techniques
?Unlike in medical trials employing standard drug preparations, surgical techniques can vary greatly from surgeon to surgeon. Surgeons also develop technical “tricks” as their experience with a procedure evolves and often personalize aspects of the procedure. These variations are difficult to quantify.

B. Timing of surgical trials
?Because a number of operations are often required before a surgeon acquires ample skills in the procedure (known as a learning curve), it is difficult to decide when to start a RCT.

C. Blinding difficulties
?Ideally researchers and patients are "blind" to the treatment received (i.e. with drug trials a control group is given a placebo). In trials comparing medical and surgical therapies, blinding may be impossible because sham operations are generally considered unethical.

D. Feasibility issues
?Rare conditions and urgent and life threatening situations cause difficulties with recruitment, consent, and randomization.
?RCTs are expensive, time consuming, and logistically complex.

E. Lack of funding and education in clinical epidemiology
?While many medical studies are supported by pharmaceutical companies, it is difficult to obtain funding for surgical trials that are unlikely to provide these companies with financial benefits.
?Surgeons' knowledge of clinical epidemiology remains poor despite relevant publications in surgical journals.

■参考URL
・Controlled Surgical Research Trials: Why Are They Important?

■参考文献
1. McCulloch P, Taylor I, Sasako M, Lovett B, Griffin D. Randomised trials in surgery: problems and possible solutions. Bmj 2002;324:1448-1451.
2. McLeod RS. Issues in surgical randomized controlled trials. World J Surg 1999;23:1210-1214.
3. Demange MK, Fregni F. Limits to clinical trials in surgical areas. Clinics (Sao Paulo) 2011;66:159-161.

■まとめ
・外科系領域においてRCTをおこなうのは難しい