乳腺MRI兼有使用过度和使用不足

根据11月18日在线发表于《美国医学会杂志-内科学》上的两项独立研究，在做乳腺MRI无益甚至可能有害的女性中存在这项检查过度使用的情况，而在可能从MRI中受益最多的女性中又存在使用不足的情况。

这两项大型的队列研究都是以收集全国社区医疗实践中乳腺MRI使用的模式的数据为目的的，纳入了不同的患者群并使用了不同的方法学，但结果出奇的相似。除了普遍存在的乳腺MRI过度使用和使用不足外，两项研究还发现这项技术的总使用率自2000年以来因多种适应证而迅猛增长，即便证据仅支持对几项特定的适应证应用这项技术，好在这种快速增长的态势在近几年中似乎保持平稳。

全国性指南支持使用MRI筛查无症状的女性，但前提是因携带BRCA基因突变、是BRCA携带者一级亲属但自己未做过相关检查而具有高乳腺癌风险或是基于家族史采用风险评估工具得出终生乳腺癌风险超过20%。

在第一项研究中，西雅图群体健康究所的Karen J. Wernli医生等人利用5家参与乳腺癌监测联合会的区域性注册处的数据评估乳腺MRI的使用。其研究对象由年龄介于18~79岁、在2005~2009年间进行了MRI(6,777位受试者进行了8,931次检查)和(或)筛查性乳腺x线摄影检查(1,288,924位受试者)的女性构成(JAMA Intern. Med. 2013 Nov. 18 [doi: 10.1001/jamainternmed.2013.11963])。

结果显示，在相对较短的研究期间，乳腺MRI的过度使用率翻了近2倍，从每1,000位女性的4.2次(2005年)增至11.5次(2007年)；然后稳定在约2,150次/年，一直延续到2009年。总体而言，进行乳腺MRI筛查的女性中仅25%被视为终生有高乳腺癌风险，满足推荐的检查标准，这个比例在2005年仅为9%，到2009年上升至29%。

研究表明，看起来其中大部分女性及其医生都高估了乳腺癌风险，他们可以利用获准的风险计算工具获得更精准的评估结果，而非单纯依赖家族史判断。在将近25,200位研究对象中不到5%的被认定为终生高乳腺癌风险的女性进行了乳腺MRI筛查。既往研究曾报告，高风险女性进行乳腺MRI最普遍的原因是幽闭恐怖症，时间约束，费用顾虑以及医生不支持手术、不注重患者利益和对这项技术缺乏了解。

在第二项研究中，哈佛医学院和哈佛朝圣者卫生保健研究所群体医学部(department of population medicine)的Natasha K. Stout医生等人在一项大型的覆盖全英格兰逾100万例患者的非盈利健康计划中评估了2000~2011年中乳腺MRI的使用情况，研究对象由10,518位年龄介于20~89岁(平均年龄，49岁)的女性构成，其乳腺MRI检查次数为18,215次。在研究期间，这项检查的总使用率增加了14倍，从2000年的198次/10,000人增至2011年的2,744次/10,000人。正如前一项研究，乳腺MRI的使用出现一个陡直上升期，这种态势一直延续至接近2008年时，随后出现平稳期。这与美国癌症协会2007年发布的指南相符，后者建议仅将乳腺MRI作为高乳腺癌风险的女性的一项筛查工具。进行乳腺MRI筛查的女性中只有21%属于高危人群，满足推荐的筛查标准。在通过BRCA状态或家族史判断处于高危的女性中进行乳腺MRI筛查者不足半数(JAMA Intern. Med. 2013 Nov. 18 [doi: 10.1001/jamainternmed.2013.11958])。

研究者表示，“明白是谁在接受乳腺MRI检查以及使用这项检查的后果应该是研究的先决条件，以确保使有限的卫生保健资金产生最大的健康收益。”

Wernli医生的研究得到国家癌症研究所和卫生保健研究与质量管理局的部分支持。Wernli医生无经济利益冲突的报告；其合作者报告与通用医疗、飞利浦医疗系统及其他公司存在联系。Stout医生的研究得到美国癌症协会和国家研究资源中心的部分支持。Stout医生及其合作者无经济利益冲突的报告。

随刊述评：技术被不当使用

Shelley Hwang医生和Isabelle Bedrosian医生指出，在未满足指南标准的女性中乳腺MRI过度使用率高得“惊人”，而在能够从中获得最大收益的女性中又存在使用不足的情况，这“明显提示了优化患者选择的必要性”。这两项研究还表明，这项技术操作仍将继续用于非筛查性目的——比如初诊的乳腺癌的分期以及治疗后监测，而在这方面尚无足够的数据支持。“对于医生和患者而言，依据数据对这项技术进行合理配置是做出最佳选择的一个必要条件”。作为医学界人员，我们肩负着一个共同的责任，就是确保乳腺MRI产生足够的临床收益，从而为活检、检查费用和患者焦虑增加等相关成本提供合理的依据(JAMA Intern. Med. 2013 Nov. 18 [doi: 10.1001/jamainternmed.2013.10502])。

Hwang医生任职于美国北卡罗来纳州达勒姆市杜克癌症研究所。Bedrosian医生任职于休斯顿市M.D.安德森癌症中心。二人均无潜在的经济利益冲突的报告。这些评论摘自Wernli医生和Stout医生报告的随刊评论。

爱思唯尔版权所有  未经授权请勿转载

By: MARY ANN MOON, Internal Medicine News Digital Network

In real-world practice, breast MRI is being overused in women who won’t benefit and might even be harmed by it, but at the same time underused by the women who could gain the most from it, according to two separate studies reported online Nov. 18 in JAMA Internal Medicine.

The two large cohort studies, which involved different patient populations and different methodologies, had remarkably similar findings. In addition to the widespread overuse and underuse of breast MRI, both studies found that overall use of the technology has soared since the year 2000 for a variety of indications, even though the evidence only supports its use for a few particular indications.

Thankfully, that rapid increase appears to have plateaued in the most recent years for which data are available, both research groups noted.

Both studies were performed simply to gather data on national patterns of breast MRI use in community practice, because of the dearth of information on this topic.

National guidelines support breast MRI to screen asymptomatic women only if they are at high risk for breast cancer because they carry BRCA gene mutations, are first-degree relatives of BRCA carriers but haven’t been tested themselves, or are at more than 20% lifetime risk of breast cancer according to risk assessment tools based on family history.

In the first study, investigators assessed breast MRI use using data from five regional registries participating in the Breast Cancer Surveillance Consortium. The study population comprised women aged 18-79 years who had breast MRI (8,931 exams in 6,777 subjects) and/or screening mammography (1,288,924 subjects) during 2005-2009, reported Karen J. Wernli, Ph.D., of Group Health Research Institute, Seattle, and her associates.

During the relatively brief study period, the overall use of breast MRI nearly tripled, from 4.2 to 11.5 exams per 1,000 women. The total number of exams rose steeply during the first 2 years, from 863 in 2005 to 2,264 in 2007; it then remained stable at about 2,150 per year through 2009.

Overall, only 25% of women who had screening breast MRI were considered at high lifetime risk for breast cancer and thus fit the recommended criteria for the procedure. That proportion was only 9% in 2005, and it rose to 29% in 2009.

It appears that most of these women and their clinicians overestimated their breast cancer risk. They may obtain more accurate assessments by using approved risk calculators rather than by relying on family history alone, Dr. Wernli and her colleagues said (JAMA Intern. Med. 2013 Nov. 18 [doi: 10.1001/jamainternmed.2013.11963]).

Conversely, fewer than 5% of the approximately 25,200 study participants deemed to be at high lifetime risk for breast cancer underwent screening breast MRI. Previous studies have reported that the most common reasons that high-risk women cite for forgoing breast MRI were claustrophobia, time constraints, financial concerns, a physician who didn’t endorse the procedure, lack of patient interest, and lack of access to the technology.

In the second study, investigators assessed the use of breast MRI from 2000 through 2011 in a large, not-for-profit health plan covering more than 1 million patients throughout New England. The study population involved 10,518 women aged 20-89 years (mean age, 49 years) who had 18,215 breast MRI exams, reported Natasha K. Stout, Ph.D., of the department of population medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, and her associates.

Overall use of the procedure increased 14-fold during the study period, from 198 per 10,000 women in 2000 to 2,744 per 10,000 in 2011. As in the previous study, there was a steep rise in breast MRI use until approximately 2008, followed by a leveling off. This coincides with the release of American Cancer Society guidelines in 2007 recommending breast MRI as a screening tool only for women at high risk of breast cancer, Dr. Stout and her colleagues said.

Only 21% of the women who underwent screening breast MRI were at high risk and thus met the recommended criteria for the procedure. And fewer than half of the women who were at high risk by virtue of their BRCA status or family history underwent breast MRI (JAMA Intern. Med. 2013 Nov. 18 [doi: 10.1001/jamainternmed.2013.11958]).

"Understanding who is receiving breast MRI and the downstream consequences of this use should be a high research priority, to ensure that the limited health care funds available are used wisely to maximize population health," Dr. Stout and her colleagues said.

Dr. Wernli’s study was supported in part by the National Cancer Institute and the Agency for Healthcare Research and Quality. Dr. Wernli reported no financial conflicts of interest; her associates reported ties to GE Medical Systems, Phillips Medical Systems, and other companies. Dr. Stout’s study was supported in part by the American Cancer Society and the National Center for Research Resources. Dr. Stout and her associates reported no financial conflicts of interest.

View on the News
Inappropriate use of technology

The "striking" overuse of breast MRI in women who didn’t meet guideline criteria and simultaneous underuse in women who could derive the greatest benefit "clearly indicate the need for better patient selection," said Dr. E. Shelley Hwang and Dr. Isabelle Bedrosian.

Both studies also showed that the procedure continues to be used for nonscreening purposes – such as for staging newly diagnosed breast cancers and post-treatment surveillance – for which there is insufficient data supporting that use.

"A thoughtful, data-driven allocation of technology is necessary for clinicians and patients to make the best choices. As a medical community, we bear a collective responsibility to ensure that breast MRI provides sufficient clinical benefit to warrant the additional biopsies, increased patient anxiety, and cost that accrue with its use," they said.

Dr. Hwang is at Duke Cancer Institute, Durham, N.C. Dr. Bedrosian is at M.D. Anderson Cancer Center, Houston. They reported no potential financial conflicts of interest. These remarks were taken from their invited commentary accompanying Dr. Wernli’s and Dr. Stout’s reports (JAMA Intern. Med. 2013 Nov. 18 [doi: 10.1001/jamainternmed.2013.10502]).