FDA批准使用超声设备对致密乳房进行筛查

9月18日，第一种用于提高致密乳房女性乳腺癌检出率的超声设备通过FDA审批，这种设备可作为一种筛查工具，与标准乳腺X线检查联合应用。2005年，SOMO-V自动乳腺超声系统(ABUS)设备被批准作为乳腺X线检查的辅助检查。FDA的最新决议扩大了其授权应用的范围，对于无乳腺癌证据且乳腺X线检查为阴性的无症状女性，也可使用这种设备进行筛查。

对于致密乳房患者，使用乳腺X线检查检出乳腺癌的难度较大，与密度较低乳房中所见的脂肪组织相比，致密乳房患者的乳腺内有大量的纤维腺体组织。“纤维腺体乳腺组织和肿瘤在乳腺X线检查中都表现为致密的白色区域。因此，致密乳腺组织可能掩盖较小的肿瘤，并可能延误乳腺癌的诊断，”FDA在声明中指出。近期一项研究报告，致密乳房不增加因乳腺癌死亡的风险，但致密乳房与乳腺癌发病风险增高相关(J. Natl. Cancer Inst. 2012 [doi:10.1093/jnci/djs327])。并且，已设法强制在乳腺X线检查报告中通告是否有致密乳房，这些患者可能获益于其他筛查。

4月，FDA放射学设备专家组以13-0的投票结果一致同意批准致密乳房女性进一步接受超声筛查。顾问专家一致认为，该设备的益处超出乳腺癌筛查中的任何风险。FDA曾对将一项关键研究的结果推广到广泛人群表示忧虑，但专家组认为非侵入性设备是安全和有效的。根据FDA的声明，女性是否患有致密乳房是由其主治医生确定的。之前接受过临床乳腺干预(如手术或活检)的女性不适合使用这种超声设备检查，“因为乳腺干预可能改变乳腺组织的超声影像”。

这项回顾性研究在美国的13个研究中心共纳入200例致密乳房女性，由委员会认证的放射科医生的回顾显示，在这一人群中，将这种设备与乳腺X线检查联合使用的乳腺癌检出率显著高于单纯使用乳腺X线检查，结果具有统计学意义。

批准的前提条件是，这种设备的生产商——总部位于加利福尼亚州Sunnyvale市的U-Systems公司必须向医生和技术人员提供全面的培训，并提供一些附加服务，包括“一份明确指出初始、定期和每年1次质量控制评估时需要系统检测的手册”。

总之，研究显示，与单纯使用乳腺X线照相检查相比，放射科医生将乳腺X线检查与超声检查获取的信息相结合，可额外发现30%的乳腺癌。ABUS有助于在致密乳房女性中检出乳腺癌，尤其是较小和较早期的乳腺癌。基于这项研究结果，FDA批准将这种设备与乳腺X线检查相结合，用于致密乳房女性的乳腺癌筛查。

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By: JANE SALODOF MACNEIL, Oncology Practice

The first ultrasound device to boost breast cancer detection in women with dense breasts won approval Sept. 18 from the Food and Drug Administration as a screening tool for use in combination with standard mammography.

The somo-v Automated Breast Ultrasound System (ABUS) device was approved in 2005 as an adjunct to mammography. This new decision broadens its authorized use to asymptomatic women who have no evidence of breast cancer and whose mammograms are negative.
 

Images: ©2011 U-Systems, Inc. All Rights Reserved.

The somo-v Automated Breast Ultrasound (ABUS) device

Whether a woman has dense breasts would be determined by a physician, according to the FDA announcement. Women who have had a previous clinical breast intervention, such as a surgery or biopsy, would not be eligible for the device, "since this might alter the appearance of breast tissue in an ultrasound image," the FDA said.

Breast cancer detection by mammography is more challenging in dense breasts, which have a high amount of fibroglandular tissue, as compared with the fatty tissue seen in less-dense breasts. "Fibroglandular breast tissue and tumors both appear as solid white areas on mammograms. As a result, dense breast tissue may obscure smaller tumors, potentially delaying detection of breast cancer," the FDA noted in its announcement.

A recent study reported dense breasts do not increase risk of death from breast cancer, but that dense breasts are associated with greater risk of developing the disease (J. Natl. Cancer Inst. 2012 [doi:10.1093/jnci/djs327]).

In addition, lobbying efforts have sought to mandate that mammography reports notify women who have dense breasts that they may benefit from additional screening.

The go-ahead for ultrasound screening follows a unanimous 13-0 endorsement in April from the agency’s Radiological Devices Panel. That advisory group agreed that the device’s benefits outweigh any risks for breast cancer screening. The FDA had been concerned about the generalization of a pivotal study to a broad population but the panel deemed the noninvasive device to be safe and effective.

The retrospective multireader study involved 200 women at 13 U.S. sites. All had dense breasts, and reviews by board-certified radiologists showed a statistically significant increase in breast cancer detection when the device was used with mammography as compared with mammography alone.

As a condition of approval, Sunnyvale, Calif.–based U-Systems Inc., which makes the device, must provide thorough training for physicians and technologists, and provide facilities with "a manual clearly defining system tests required for initial, periodic, and yearly quality control measures."

"Enabling radiologists to use the information obtained from mammography and integrate that with the information obtained with ultrasound, leverages the potential of ABUS in a screening environment to find the 30% additional cancers that would not have been found with mammography alone," said Ron Ho, president and CEO of U-Systems, maker of the somo-v ABUS. "Research shows that ABUS can help find cancer in women with dense breasts, and that the cancers are smaller and early stage. With formal approval, we are moving rapidly from development to commercialization and look forward to making the somo-v ABUS system more widely available across the United States."