經肛門內視鏡微創手術對切除直腸病灶成效良好


  June 26, 2007 — 經肛門切除(TA)是外科切除局部直腸病灶最常用的方法,但根據發表於密蘇里聖路易斯美國大腸與直腸外科醫師協會年會的研究數據,經肛門內視鏡微創手術(TEM)可能提供相較於標準程序更多的好處;在一項比較TA與TEM的研究中,結果顯示TEM是切除局部直腸腫瘤的術式首選。
  
  當TEM在美國較為不普遍時,其在歐洲早已使用超過20年,且由德國Tubingen大學Gerhard Buess醫師在這個領域為領先者;根據資深研究者布靈頓Vermont大學Peter Cataldo醫師表示,在美國,進行這項術式的機構不超過100個機構;Cataldo醫師是該機構外科助理教授。
  
  Cataldo醫師解釋,TEM是一種微創手術,它提供放大後的視野以及更好的成像,在整個直腸中移除腫瘤,但是隨著這項技術越來越受到歡迎,技術卻一直無法跟上。
  
  Cataldo醫師向Medscape表示,主要有三個原因造成這樣的情形;首先,適合進行這項術式的病患並不是那麼多;其次,這是項不容易學習的技術;最後,其所需要的器材是昂貴的。
  
  因此,截至目前,並沒有大型研究比較TEM與TA的療效;在這項回溯性分析研究中,研究者比較TEM與TA,針對良性與惡性直腸腫塊進行研究;這個族群由171位於1990年到2006年之間,接受TA或是TEM(82位病患接受TEM、89位病患接受TA)切除腺瘤或是息肉的病患組成,這兩組病患的流行病學參數,例如年齡、性別、與病灶形式、分級與大小相似,平均追蹤達34個月。
  
  相較於TA,TEM術式較容易達到完全切除,且沒有留下邊緣(88%相較於71%),無論該病灶是良性還是惡性的;且相較於TA,TEM術式較容易得到完整的、非片段的樣本(94%相較於63%)。
  
  Cataldo醫師表示,以TEM得到的樣本總是完整的,這使得病理學家更容易分析這些樣本。
  
  接受TEM的病患,其局部與遠端再發率也是顯著低於接受TA病患(5%相較於25%),尤其是局部再發率,不論是良性還是惡性病灶,進行TEM術式後都顯著地降低(4%相較於20%),這兩組發生併發症的比例相當。
  
  Cataldo博士解釋,可能因為TEM能更精確將腫瘤切除,因此有較低的復發率與較佳的存活率。
  
  Cataldo博士表示,整體而言,經肛門內視鏡微創手術是通入直腸較好的選擇,因為可看到整個直腸,這個視野較能幫助切除,且能更準確切入包覆的直腸腫瘤。
  
  進行TEM的一項缺點是此設備的費用,當進行TA手術使用標準的外科儀器,TEM設備所耗費的金額是美金60,000至80,000元,Cataldo博士解釋,除了設備的費用外,學習曲線也是陡峭的,必要的是,外科醫生必須要有適當的個案數去發展及維持此技術。
  
  然而,一旦掌握此技術,此過程並不十分困難,大約只需耗費1小時到1小時15分左右,更重要的是,對許多病患而言,可避免腹部開刀與結腸造口術。
  
  美國大腸與直腸外科醫師協會年會:GSF1摘要;2007年6月5日發表。
  

Transanal Endoscopic Microsurg

By Roxanne Nelson
Medscape Medical News

June 26, 2007 — Transanal excision (TA) is the most common method of surgically excising local rectal lesions, but data presented at the annual meeting of the American Society of Colon and Rectal Surgeons, in St. Louis, Missouri, suggests that transanal endoscopic microsurgery (TEM) may offer certain advantages over the more standard procedure. In a study that compared TA with TEM, results showed that TEM was the technique of choice for excising local rectal neoplasms.

While still relatively uncommon in the United States, TEM has been used for more than 2 decades in Europe and was pioneered in Germany by Gerhard Buess, MD, from the University of Tübingen. In the United States, there are less than 100 facilities that perform the procedure, according to senior investigator Peter Cataldo, MD, and less than 10 that excise a significant number of lesions using TEM. The largest number of TEM procedures performed in the United States is at the University of Vermont, in Burlington, where Dr. Cataldo is an associate professor of surgery.

TEM is a minimally invasive approach that provides magnified vision and superior optics for removing tumors throughout the entire rectum, explained Dr. Cataldo. But while it is starting to become more popular, the technique has been slow to catch on.

"There are 3 primary reasons for that," Dr. Cataldo told Medscape. "There are not many facilities that see enough patients who are candidates for the procedure. The second reason is that it is a difficult technique to learn. And third, the equipment is expensive."

Thus far, there have been no large clinical trials comparing the efficacy of TEM with TA. In this retrospective study, the researchers compared TEM with TA for both benign and malignant rectal masses. The cohort encompassed 171 patients who underwent either TA or TEM (82 patients TEM, 89 TA) for adenocarcinoma or polyps between 1990 and 2006. Both patient groups were similar in demographics such as age, sex, and lesion type, stage, and size, with a mean follow-up of 34 months.

The TEM procedure was much more likely to result in a complete resection and yield negative margins, as compared with TA (88% vs 71%). This was true whether the lesion was benign or malignant. It was also more likely to produce an intact, nonfragmented specimen, as compared with TA (94% vs 63%).

"With TEM it almost always comes out as an intact specimen, and that makes it much easier for the pathologist to evaluate," said Dr. Cataldo.

The rate of recurrence, both local and distant, was also lower in patients who had undergone TEM, as compared with TA (5% vs 25%). This was particularly true for rates of local recurrence, which were significantly lower for both benign and malignant lesions following TEM (4% vs 20%). The rate of complications was similar between both groups.

The lower rates of recurrence and better overall survival are probably due to the fact that TEM allows for a more precise tumor resection, explained Dr. Cataldo.

"Overall, rectal access is vastly superior with transanal endoscopic microsurgery, because you can visualize the entire rectum," said Dr. Cataldo. "The visualization is superior to transanal excision, and these attributes translate into a much more precise incision enclosure of the rectal masses."

One drawback of the procedure is the cost of the equipment needed to perform TEM. While the TA procedure can be performed with standard surgical instruments, the cost of TEM equipment ranges from $60,000 to $80,000. Aside from the associated expense of the equipment, the learning curve is steep, explained Dr. Cataldo. It is essential, therefore, that surgeons have an adequate number of cases to develop and maintain expertise in this technique.

"But once you've mastered it, the procedure is not terribly difficult to perform and takes about an hour to an hour and 15 minutes to perform," he said. "But most important, in many patients, you can avoid the need for an abdominal operation and possibly the need for a colostomy in some circumstances."

Annual meeting of the American Society Colon and Rectal Surgeons: Abstract GSF1. Presented June 5, 2007.

    



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