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作者：Laurie Barclay, MD  
出處：WebMD醫學新聞

　　December 14, 2009 — 根據發表於12月14/28日版內科醫學誌(Archives of Internal Medicine)的大型世代研究結果，對於有非轉移大腸直腸癌病史的男性，體能活力程度越高，則大腸直腸癌死亡率和整體死亡率都較低。
　　
　　波士頓麻州綜合醫院、哈佛醫學院、達那-法柏癌症研究治療中心的Jeffrey A. Meyerhardt醫師等人寫道，雖然體能較活躍者發生大腸直腸癌的風險較低，少有研究檢視運動對於大腸直腸癌存活者是否有利。
　　
　　研究者使用「Health Professionals Follow-up Study」這項研究的資料，檢視大腸直腸癌死亡率與整體死亡率，在診斷後根據事先定義的體能類別分類，研究對象是668名有第1-3期大腸直腸癌病史的男性，診斷時無明顯轉移。診斷後6個月內死亡的男性不納入體能評估，以減少可能與復發有關的偏差。
　　
　　超過半數(50.4%)的研究對象每週運動代謝當量(MET)達18小時以上。體能活力增加顯著與降低大腸直腸癌死亡率(趨勢P值 = .002)和整體死亡率(趨勢P值< .001)有關。相較於每週MET時數小於等於3小時者，每週MET時數大於27小時之男性的大腸直腸癌死亡率校正風險比為0.47(95%信心區間為0.24 - 0.92)。診斷前的年紀、疾病分期、身體質量指數(BMI)、診斷年數、腫瘤位置與體能活力等，並不會影響體能活動的明顯好處。
　　
　　研究作者們寫道，對於非轉移大腸直腸癌病史的男性世代，體能活動程度越高，則大腸直腸癌死亡率和整體死亡率都較低。
　　
　　研究限制包括，死亡率原因之外缺乏癌症復發資料，缺乏治療資料，世代的同質性本質，可能受到共病症和取得健康照護程度的影響。此外，資料僅限於休閒活動，並未包括職業運動。
　　
　　研究作者們寫道，這些結果支持在大腸直腸癌診斷後運動以降低死於此病的風險。有一個針對高風險第2期和第3期大腸癌存活者的隨機研究，比較一般教育資料以及涵蓋監督體能課程的計畫與行為支持，結果即將公佈；其主要終點為無病存活。發表的研究結果支持此類研究努力。
　　
　　疾病管制與預防中心的Janet E. Fulton博士等人在編輯評論中表示，這些研究增加了體能活躍的生活型態有助於健康的證據。
　　
　　編輯們寫道，放眼未來，對體能活動有更科學的瞭解是重要的，學習如何推廣這些科學發現讓大眾採用也一樣重要。即使是小量的體能活動、產生不等的體力貢獻，都會對健康有所助益。
　　
　　國家健康研究中心支持本研究。研究作者與編輯皆宣告沒有相關財務關係。編輯們的意見並不一定代表疾病管制與預防中心和國家、心臟肺臟與血液研究中心的立場。


Physical Activity Linked to Better Survival in Men With Colorectal Cancer

By Laurie Barclay, MD
Medscape Medical News

December 14, 2009 — In men with a history of nonmetastatic colorectal cancer, more physical activity was associated with a lower risk for colorectal cancer–specific and overall mortality, according to the results of a large cohort study reported in the December 14/28 issue of the Archives of Internal Medicine.

"Although physically active individuals have a lower risk of developing colorectal cancer, few studies have examined whether exercise benefits colorectal cancer survivors," write Jeffrey A. Meyerhardt, MD, MPH, from Dana-Farber Cancer Institute, Harvard Medical School and Massachusetts General Hospital in Boston, and colleagues.

Using data from the Health Professionals Follow-up Study, the investigators examined colorectal cancer–specific and overall mortality rates, based on predefined physical activity categories after diagnosis, in 668 men who had a history of stage I to stage III colorectal cancer and no apparent metastases at diagnosis. Men who died within 6 months of their postdiagnosis physical activity evaluation were excluded to reduce bias related to occult recurrences.

More than half (50.4%) of the study cohort exercised 18 metabolic equivalent task (MET) hours per week or more. Increased physical activity was significantly associated with lower colorectal cancer–specific mortality rate (P = .002 for trend) and lower overall mortality rate (P < .001 for trend). Compared with men who participated in 3 or less MET hours per week of physical activity, those who participated in more than 27 MET hours per week of physical activity had an adjusted hazard ratio for colorectal cancer–specific mortality of 0.47 (95% confidence interval, 0.24 - 0.92). Age, disease stage, body mass index (BMI), diagnosis year, tumor location, and physical activity before diagnosis did not appear to affect the apparent benefit of physical activity.

"In a large cohort of men with a history of nonmetastatic colorectal cancer, more physical activity was associated with a lower risk of colorectal cancer–specific and overall mortality," the study authors write.

Limitations of this study include lack of data on cancer recurrences beyond cause of mortality, lack of treatment data, homogeneous nature of the cohort, and possible confounding by comorbidities and access to healthcare. In addition, data were limited to leisure-time exercise and did not include occupational physical activity.

"These results provide further support that physical activity after colorectal cancer diagnosis may lower the risk of death from that disease," the study authors write. "A randomized study among high-risk stage II and stage III colon cancer survivors that will compare the use of general education materials with a program that includes supervised physical activity sessions and behavioral support delivered over 3 years will soon open; the primary end point is disease-free survival. The findings from the present study further support that effort."

In an accompanying editorial, Janet E. Fulton, PhD, from the Centers for Disease Control and Prevention in Atlanta, Georgia, and colleagues note the increasing evidence that a physically active lifestyle benefits health.

"As we look to the future, a better understanding of the science of physical activity is essential," the editorialists write. "Learning how best to promote the findings of that science for public consumption and adoption is equally vital....Even small physical activity contributions to a diverse physical activity portfolio can produce multiple health dividends."

The National Institutes of Health supported this study. The study authors and editorialists have disclosed no relevant financial relationships. The opinions of the editorialists do not necessarily represent the official position of the Centers for Disease Control and Prevention or the National Heart, Lung, and Blood Institute.

Arch Intern Med. 2009;169:2102-2108, 2124-2127.