二甲双胍对糖尿病患者患肺癌的影响与其吸烟史相关

《美国癌症研究协会》杂志中Lori Sakoda博士的一项研究表明，糖尿病患者中不吸烟的人服用二甲双胍可降低患肺癌的风险。

一些实验室研究和观察性研究表明，二甲双胍可能有助预防癌症，但人体试验的数据却与之相互矛盾，Sakoda解释道。研究人员进行了深入研究以阐明使用二甲双胍和肺癌风险之间的联系。

Sakoda和他的同事们进行了一项回顾性队列研究健康调查，在1994年和1996年之间，有47351名40岁及以上的糖尿病患者(54%的男性)纳入了此项研究。糖尿病药物的信息来自电子药房记录。其中大约46%的人曾经服用过二甲双胍（六个月内服用过两个或两个以上含有二甲双胍的处方）。

在15年的随访中，747名患者被诊断出患有肺癌。80人为不吸烟者，203人是现在吸烟者。研究表明二甲双胍与降低整体肺癌风险无关，然而，未吸烟的糖尿病患者服用二甲双胍后，患肺癌的风险会降低43%，而且持续服用风险会更低。不吸烟者服用二甲双胍五年或更长时间，其患肺癌的风险性降低52%，但是这个结果无显著统计学意义。

服用二甲双胍五年或更长时间患腺癌的风险会降低31%，腺癌是一种经常在非吸烟者中诊断出的肺癌。患小细胞癌的风险增加了82%，这是一种经常在吸烟者中诊断出的肺癌，这些研究结果具有统计学意义。

Sakoda说，“当我们观察所有的糖尿病患者时，服用二甲双胍与肺癌风险性无关。然而我们的研究结果表明，患肺癌风险性可能与吸烟史相关。服用二甲双胍会降低不吸烟者患肺癌的风险，增加吸烟者患肺癌的风险。未来需要进一步的研究澄清二甲双胍是否可以用来防止肺癌或其他癌症，特别是特定人群中的不吸烟者。”（转化医学网360zhyx.com）

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附原文：Among nonsmokers who had diabetes, those who took the diabetes drug metformin had a decrease in lung cancer risk, according to a study in Cancer Prevention Research, a journal of the American Association for Cancer Research,by Lori Sakoda, PhD, MPH, research scientist at the Kaiser Permanente Division of Research in Oakland, California.

Some laboratory studies and a number of observational studies suggest that metformin may prevent cancer, but the data from human studies, however, are conflicting, explained Sakoda. The researchers conducted this study to further clarify the association between metformin use and lung cancer risk.

Sakoda and colleagues conducted a retrospective cohort study of 47,351 diabetic patients (54 percent men), 40 years or older, who completed a health-related survey between 1994 and 1996. Information on their diabetes medications was collected from electronic pharmacy records. About 46 percent of them were "ever-users" of metformin, defined as those who filled two or more prescriptions within a six-month period.

During 15 years of follow-up, 747 patients were diagnosed with lung cancer. Of them, 80 were nonsmokers, and 203 were current smokers.

Metformin use was not associated with lower lung cancer risk overall; however, the risk was 43 percent lower among diabetic patients who had never smoked, and the risk appeared to decrease with longer use. Nonsmokers who used metformin for five years or longer had a 52 percent reduction in lung cancer risk, but this finding was not statistically significant.

Metformin use for five or more years was associated with a 31 percent decrease in the risk for adenocarcinoma, the most common type of lung cancer diagnosed in nonsmokers, and an 82 percent increase in the risk for small-cell carcinoma, a type of lung cancer often diagnosed in smokers, but neither of these findings were statistically significant.

In an interview, Sakoda said, "Metformin use was not associated with lung cancer risk when we looked at all patients with diabetes. However, our results suggest that risk might differ by smoking history, with metformin decreasing risk among nonsmokers and increasing risk among current smokers. Our results suggesting that the risk associated with metformin might differ by smoking history were unexpected. Additional large, well-conducted studies are needed to clarify whether metformin may be used to prevent lung or other cancers, particularly in specific subpopulations, such as nonsmokers."