BMC Cancer：糖尿病恶化乳腺癌患者预后

　　《生物医学中心癌症》（BMC Cancer）杂志2012年12月26日在线发表的一项研究指出，既往未诊断出糖尿病的老年乳腺癌患者，其临床分期和死亡率更高。

　　该研究是一项基于Seer-medicare数据库的观察性队列研究。研究者利用来自Surveillance、Epidemiology和End Results-Medicare linked database中的数据，对2001年1月至2005年12月间确诊罹患乳腺癌与糖尿病的女性患者进行观察。研究者利用医疗保险索赔数据库对患者进行鉴别，将乳腺癌确诊前4-24个月确诊糖尿病者，定义为既往诊断糖尿病；癌症确诊前3个月至确诊后3个月内仍未诊断出糖尿病，则归为既往未诊断糖尿病者。

　　研究共纳入2418例患者，平均年龄77.8岁，其中634（26%）例既往未诊断出糖尿病49.4%的患者临床分期为原位癌或1期乳腺癌。对患者进行随访至2007年12月，或随访至患者死亡。

　　多变量分析结果表明，年龄80岁以上（占队列中的40%）、罹癌前卫生保健体系（初级护理医师/预防措施）不完善的既往未诊断糖尿病患者，其经校正危险比更高。既往未诊断糖尿病患者，临床分期为癌症晚期（III/IV）的经校正危险比更高（比值比1.37，95% 可信区间1.05 -- 1.80; P = 0.02），经校正的其他原因（癌症之外）死亡危险比也更高（危险比1.29，95%可信区间1.02 -- 1.63; P = 0.03）。

　　既往多项研究已经证实糖尿病可恶化乳腺癌预后。研究者指出，既往未诊断的糖尿病与乳腺癌临床分期及死亡率较高相关，糖尿病与乳腺癌之间的病理生理关系需要进一步研究证实。

Epidemiology and outcomes of previously undiagnosed diabetes in older women with breast cancer: an observational cohort study based on seer-medicare

Background

In breast cancer, diabetes diagnosed prior to cancer (previously diagnosed) is associated with advanced cancer stage and increased mortality. However, in the general population 40% of diabetes is undiagnosed until glucose testing, and evidence suggests one consequence of increased evaluation and management around breast cancer diagnosis is the increased detection of previously undiagnosed diabetes. Biological factors -- for instance, higher insulin levels due to untreated disease - and others underlying the association between previously diagnosed diabetes and breast cancer could differ in those whose diabetes remains undiagnosed until cancer. Our objectives were to identify factors associated with previously undiagnosed diabetes in breast cancer, and to examine associations between previously undiagnosed diabetes and cancer stage, treatment patterns, and mortality.

Methods

Using Surveillance, Epidemiology, and End Results-Medicare, we identified women diagnosed with breast cancer and diabetes between 01/2001 and 12/2005. Diabetes was classified as previously diagnosed if it was identified within Medicare claims between 24 and 4 months before cancer diagnosis, and previously undiagnosed if it was identified from 3 months before to <= 3 months after cancer. Patients were followed until 12/2007 or death, whichever came first. Multivariate analyses were performed to examine risk factors for previously undiagnosed diabetes and associations between undiagnosed (compared to previously diagnosed) diabetes, cancer stage, treatment, and mortality.

Results

Of 2,418 patients, 634 (26%) had previously undiagnosed diabetes: the remainder had previously diagnosed diabetes. The mean age was 77.8 years, and 49.4% were diagnosed with in situ or stage I disease. Age > 80 years (40% of the cohort) and limited health system contact (primary care physician and/or preventive services) prior to cancer were associated with higher adjusted odds of previously undiagnosed diabetes. Previously undiagnosed diabetes was associated with higher adjusted odds of advanced stage (III/IV) cancer (Odds Ratio = 1.37: 95% Confidence Interval 1.05 -- 1.80; P = 0.02), and a higher adjusted mortality rate due to causes other than cancer (Hazard Ratio = 1.29; 95% CI 1.02 -- 1.63; P = 0.03).

Conclusions

In breast cancer, previously undiagnosed diabetes is associated with advanced stage cancer and increased mortality. Identifying biological factors would require further investigation.