抽菸與扁平腺瘤有關
作者：Laurie Barclay, MD
出處：WebMD醫學新聞
June 17, 2010 — 根據發表於胃腸內視鏡期刊(Gastrointestinal Endoscopy)的前瞻橫斷面研究結果，由於抽菸與扁平腺瘤有關，抽菸者須以高解析度大腸鏡檢查偵測扁平腺瘤。
法明頓康乃狄克大學健康中心、Neag綜合癌症中心、第一作者Joseph C. Anderson醫師在新聞稿中表示，對於這些扁平病灶的風險因素所知有限，而此類病灶佔了高解析度大腸鏡檢查所有腺瘤的半數。許多篩檢研究顯示抽菸是大腸直腸腫瘤的重要風險因素，本研究的目標是探討接受大腸鏡篩檢之一般風險程度研究對象的扁平腺瘤風險因素。
在一所大學醫院的內視鏡中心，使用高解析度(1080i訊號)廣角(170°視野)大腸鏡為600名無症狀病患篩檢大腸直腸癌(colorectal cancer，CRC)。研究對象也提供他們的人口統計學因素、糖尿病和其他醫療狀況、藥物、家族CRC病史、飲食和抽菸史等資料。初步終點為，根據日本研究協會分類準則進行息肉形態學評估。
多變項分析之後，抽菸(重度抽菸者相較於未抽菸者)與任何大小的扁平腺瘤(校正勝算比[OR]為2.53；95% CI為1.60 - 4.00)，直徑大於等於6 mm的扁平腺瘤(校正OR為3.84；95% CI為2.02 - 7.32)，扁平惡化腺瘤(校正OR為2.81；95% CI為1.08 - 7.30)有關。
研究作者寫道，抽菸和我們的扁平腺瘤有關，我們的發現可以解釋，相較於非抽菸者，抽菸者較早發生的CRC在出現時即比較後期，抽菸者需要使用高解析度大腸鏡檢查來偵測扁平腺瘤。
研究限制包括橫斷面研究設計、研究對象主要是年輕人口、可能有其他干擾因素、缺乏初次發現扁平腺瘤時的抽菸狀態資料。
華盛頓大學醫學院的Dayna Early醫師在編輯評論中表示，扁平病灶比息肉樣病變更難發現，但是本研究的這些資料並未支持抽菸者使用進階影像檢查。
Early醫師表示，應該持續重視高品質的篩檢檢查與良好的腸道準備，因為這些對偵測右側病灶相當重要，最後，我們不只要找出抽菸者的扁平腺瘤，而是接受篩檢式大腸鏡檢查的所有病患，且使用有助於我們現有的最佳技術。
Stony Brook大學一般臨床研究中心支持本研究，研究作者和Early醫師皆宣告沒有相關財務關係。
Smoking Linked to Flat Adenomas
By Laurie Barclay, MD
Medscape Medical News
June 17, 2010 — Because smoking is associated with flat adenomas, smokers may require screening with high-definition colonoscopes to detect flat adenomas, according to the results of a prospective cross-sectional study reported in the issue of Gastrointestinal Endoscopy.
"Little is known regarding the risk factors for these flat lesions, which may account for over one-half of all adenomas detected with a high-definition colonoscope," said lead author Joseph C. Anderson, MD, from Neag Comprehensive Cancer Center, University of Connecticut Health Center in Farmington, in a news release. "Smoking has been shown to be an important risk factor for colorectal neoplasia in several screening studies. The aim of this study was to investigate smoking as a risk factor for flat adenomas in an average risk population undergoing screening colonoscopy."
At a university hospital endoscopy center, 600 asymptomatic patients presenting for colorectal cancer (CRC) screening were screened with a high-definition (1080i signal) wide-angle (170° field of view) colonoscope. Participants also provided information regarding demographic factors, diabetes and other medical conditions, medications, family history of CRC, diet, and smoking history. The primary endpoint was polyp morphology evaluated according to the Japanese Research Society Classification criteria.
After multivariate analysis, smoking (heavy smokers vs nonsmokers) was associated with flat adenoma of any size (adjusted odds ratio [OR], 2.53; 95% CI, 1.60 - 4.00), with flat adenoma 6 mm in diameter or greater (adjusted OR, 3.84; 95% CI, 2.02 - 7.32), and with flat advanced adenomas (adjusted OR, 2.81; 95% CI, 1.08 - 7.30).
"Smoking was associated with flat adenomas in our population," the study authors write. "Our findings may explain the earlier onset of CRC in smokers as well as the advanced stage with which they present, with compared with nonsmokers. Smokers may require screening with high-definition colonoscopes to detect flat adenomas."
Limitations of this study include cross-sectional design, predominantly young population, possible unmeasured confounders, and lack of data on smoking status when flat adenomas first developed.
In an accompanying editorial, Dayna Early, MD, from Washington University School of Medicine in St. Louis, Missouri, notes that flat lesions are more difficult to identify than polypoid lesions but that data to support use of advanced imaging in smokers are not available from this study.
"Ongoing emphasis should be placed on high-quality screening examinations and good bowel preparation because these are critical in detecting right-sided lesions," Dr. Early said. "Finally, we should be on the lookout for flat adenomas not only in smokers, but in all patients undergoing screening colonoscopy and use the best technology available to us to do so."
The Stony Brook University General Clinical Research Center supported this study. The study authors and Dr. Early have disclosed no relevant financial relationships.
Gastrointest Endosc. 2010;71:1234-1240, 1241-1243.
