Eicosapentaenoic acid (EPA, an omega-3 fatty acid from fish oils) for the treatment of cancer cachexia

 

Abstract

Background

Cancer cachexia is a distressing weight loss syndrome commonly seen in advanced cancer patients. It is associated with reduced quality of life and shorter survival time. Eicosapentaenoic acid (EPA) is a long chain polyunsaturated fatty acid found naturally in some fish which has been used to decrease weight loss, promote weight gain and increase survival times in patients affected with cancer cachexia.

Objectives

To evaluate the effectiveness and safety of EPA in relieving symptoms associated with the cachexia syndrome in patients with advanced cancer.

Search methods

Studies were sought through an extensive search of a range of electronic databases. Hand searching was conducted on selected journals and reference lists as well as contact made with investigators, manufacturers and experts. The most recent electronic search was conducted in February 2005.

Selection criteria

Studies were included in the review if they assessed oral EPA compared with placebo or control in randomised controlled trials of patients with advanced cancer and either a clinical diagnosis of cachexia or self-reported weight loss of 5% or more.

Data collection and analysis

Both methodological quality evaluation of potential trials and data extraction were conducted by two independent review authors.

Main results

Five trials (involving 587 participants) met the inclusion criteria. Three trials compared EPA at different doses with placebo with two outcomes, nutritional status and adverse events comparable across two of the three included trials. In addition, two trials compared different doses of EPA with an active matched control. It was possible to compare the outcomes of weight, quality of life and adverse events across these two trials. There were insufficient data to define the optimal dose of EPA.

Authors' conclusions

There were insufficient data to establish whether oral EPA was better than placebo. Comparisons of EPA combined with a protein energy supplementation versus a protein energy supplementation (without EPA) in the presence of an appetite stimulant (Megestrol Acetate) provided no evidence that EPA improves symptoms associated with the cachexia syndrome often seen in patients with advanced cancer.

 

Plain language summary

Using an omega-3 fatty acid made from fish oils to treat cancer related weight loss

There was insufficient evidence to support the use of oral fish oil (on its own or in the presence of other treatments) for the management of the weight loss syndrome often seen in patients with advanced cancer. Many people with advanced cancer develop a distressing weight loss syndrome. To date, treatment of associated symptoms has proved difficult. More recently, novel approaches have included the use of oral fish oils that can contain the omega-3 fatty acid eicosapentaenoic acid (or EPA) to stabilise weight loss and promote weight gain. This review of trials found that in weight losing persons with advanced pancreatic cancer, an EPA nutritional supplement was no better than a non EPA nutritional supplement. However, there was insufficient evidence to draw conclusions about its use in patients who have cancer of other tumour types.

 

摘要

背景

以二十碳五烯酸(EPA，1種從魚油中取出的omega3脂肪酸治療癌症惡質病

癌症惡質病是1種令人痛苦的體重減輕症候群，而且通常會發生在後期癌症患者的身上。它會使得生活的品質下降，也會讓存活的時間變短。二十碳五烯酸(EPA)是1種長鏈的多元不飽和脂肪酸，天生就存在於某些魚類的體內，而且對於受到癌症惡質病所影響的患者們來說，它已經被用來減少體重減輕的狀況、促進體重增加，並且延長生存的時間。

目標

對於患有後期癌症的患者們而言，在緩解因為惡質病症候群所帶來的症狀時，要評估二十碳五烯酸的功效與安全性。

搜尋策略

深入搜尋一系列的電子資料庫以找出相關研究，並且人工搜尋精選期刊以及參考文獻清單，並且與研究人員、廠商還有專家聯絡。最近一次進行電子搜尋的時間為2005年2月。

選擇標準

針對患有後期癌症的患者們，如果他們同時又有某種關於惡質病的臨床診斷結果，或是在自我報告中曾經有體重減輕了5%或是更多的情況，如果在相關的隨機對照試驗當中曾經有研究以安慰劑或是對照組來當作比較的對象，然後評估過口服的二十碳五烯酸，那麼這些研究就會被收集在內。

資料收集與分析

有2位獨立的審稿作者，曾經針對有潛在價值的試驗完成了方法方面的品質評估，並且擷取出資料。

主要結論

共有5項試驗(包含了587名患者)符合了收集的標準。有3項研究以2種結果來將不同劑量的二十碳五烯酸與安慰劑進行了比較，其中這2種結果為營養狀態與不良事件，而且對於這3項被收集在內的試驗當中的2項而言，上述的結果也可以跟它們相提並論。除此之外，有2項試驗曾經將不同劑量的二十碳五烯酸與某種現行且可配合的對照組進行了比較。若是在這2項試驗之間，想要比較體重、生活品質，以及不良事件等項目的各種結果，也是有可能的。但是如果想要定義出最佳的二十碳五烯酸之劑量，並沒有足夠的資料。

作者結論

並沒有足夠的資料可以認定口服的二十碳五烯酸是否會比安慰劑還要更理想。若是將二十碳五烯酸與1種蛋白質的能量補充物結合起來，相較於1種出現在某種開胃物質當中的蛋白質型能量補充物(沒有加上二十碳五烯酸)，這樣的比較並不能提供任何證據顯示二十碳五烯酸可以改善因為惡質病症候群所帶來的症狀，其中的惡質病症候群通常會發生在患有後期癌症的患者們身上。

翻譯人

此翻譯計畫由臺灣國家衛生研究院(National Health Research Institutes, Taiwan)統籌。

總結

對於患有後期癌症的患者們經常會產生的體重減輕症候群而言，針對為了治療這樣的症候群而使用口服型魚油(就它本身的狀態或是有搭配其他的治療方法)來看，並沒有充足的證據能夠加以支持。很多患有後期癌症的患者們，都會演變成某種令人痛苦的體重減輕症候群。到目前為止，人們已經證實相關的症狀在治療的時候會有困難。更加近期的時候，在新型的方法之中已經加入了使用口服魚油這個項目以穩定體重減輕的狀況，並促進體重上升，其中這些魚油可能會含有omega3脂肪酸的二十碳五烯酸(或是EPA)。本篇回顧發現，對於患有後期胰臟癌而且又有體重減輕現象的人們來說，任何1種二十碳五烯酸的營養補充品並不會勝過任何1種非二十碳五烯酸的營養補充品。然而，對於患有其他類型之腫瘤的患者們而言，並沒有充分的證據能夠針對使用它的觀點來歸納出結論。