Division of Biomedical Sciences, School of Pharmacy, University of Nottingham Malaysia.
Asian Pac J Cancer Prev. 2020 Apr 1;21(4):881-895. doi: 10.31557/APJCP.2020.21.4.881.
Conducting systematic review to evaluate plant use as a risk factor to cancer could be challenging. A systematic and well-balanced method should be applied to accommodate in vivo and in vitro studies to make a final decision. In this article, khat, a recreational plant used in some Arabic and African regions, was employed as an example to systematically determine its relationships to the premalignant and cancerous conditions.
Systematic database search was performed to recruit original human, animal or in vitro studies on khat and cancer. Sixteen studies fulfilled the inclusion criteria and subjected to assessment using Risk of Bias (RoB). Office of Health and Translation (OHAT) approach was used to rate the confidence level in the body of evidence. The evidence was integrated to establish the relationships between khat, premalignant conditions and cancer.
Seven out of eight studies showed that khat causes premalignant oral lesions with moderate evidence level. Four studies showed that khat causes cancer with low evidence level and another three studies showed that khat has anti-cancer effect with moderate to high evidence level. Only one study suggested that khat is unrelated to cancer.
RoB and OHAT approach are reliable systematic tools to evaluate plant risk to cancer and provide objective and uniform summary regardless of the study type. In conclusion, our pooled analysis did not find a direct relationship between khat and cancer but anti-cancer effect would require to be proofed on human studies.
进行系统评价以评估植物使用作为癌症风险因素可能具有挑战性。应该应用系统和平衡的方法来容纳体内和体外研究，以做出最终决策。本文以阿拉伯和非洲部分地区使用的消遣性植物卡特草为例，系统地确定其与癌前病变和癌症的关系。
系统地在数据库中搜索有关卡特草和癌症的原始人类、动物或体外研究。有 16 项研究符合纳入标准，并使用偏倚风险（RoB）进行评估。使用卫生和翻译办公室（OHAT）方法来评估证据体的置信度水平。整合证据以建立卡特草、癌前病变和癌症之间的关系。
8 项研究中有 7 项表明卡特草会导致具有中度证据水平的癌前口腔病变。四项研究表明卡特草会导致癌症，证据水平较低，另有三项研究表明卡特草具有中度到高度证据水平的抗癌作用。只有一项研究表明卡特草与癌症无关。
RoB 和 OHAT 方法是评估植物致癌风险的可靠系统工具，无论研究类型如何，都能提供客观和统一的总结。总之，我们的汇总分析没有发现卡特草与癌症之间存在直接关系，但抗癌作用需要在人体研究中得到证明。
