乳腺导管灌流术可望查出早期乳癌

    一项用来检测微小乳房肿瘤的新技术即将问世，可以检测出乳房X射线照片不能显示的病变。
    该技术是乳腺导管灌流术，就是用生理盐水“洗”乳腺导管并检查癌前期或癌变细胞，目前尚处于试验阶段。这是一种敏感而且相对简单的检查方法，能够帮助医生发现不能被乳房X射线照片检查出来的早期的癌细胞。该技术也为部份乳房组织非常致密，乳房X射线照片效果不好的妇女提供了一种新的查癌选择。整个操作过程大约需要半个小时。如果检查发现了癌前期细胞，就可对该妇女进行更仔细检查以了解会否发展成癌。

    美国马里兰州巴尔的摩市约翰斯·霍普金斯大学医学院的研究人员解释说，乳腺癌大多数在乳腺导管的内膜发生，肿瘤会释放出细胞，并可在乳腺导管灌洗液中检测出。研究小组检查了三组妇女乳腺导管液体样本中被甲基化过程的一个指标，这个过程的标记出现提示妇女有乳腺癌或癌症前期细胞。结果发现，20位患乳腺肿瘤的妇女中有17位出现甲基化标记、7名乳腺导管癌妇女中有2名出现甲基化标记，而在45名未患癌症的妇女中仅仅检测到5例存在甲基化标记。

    乳腺导管灌流术有可能最终成为乳癌常规检测的手段。该项检查可以帮助妇女早期使用预防乳房癌的药物。不过，研究人员强调，需要更大规模的研究来确定导管灌流检测乳腺癌是否有效。

    Procedure May Detect Early Breast Cancer
    NEW YORK (Reuters Health) - An experimental technique may one day be used to detect breast tumors that are too small to show up on a mammogram, researchers report.

    The procedure, known as ductal lavage, involves ``washing‘‘ breast milk ducts with saline and examining cells for signs of precancerous or cancerous changes. Dr. Saraswati Sukumar of Johns Hopkins University School of Medicine in Baltimore, Maryland, who led the new research, explained that breast cancer most often begins in the cells lining the milk ducts.

    If tumors are present in the breast, they will shed cells that can be detected in the fluid washed through the ducts, she said in an interview with Reuters Health.

    Sukumar‘s team examined samples of ductal fluid from women with breast cancer and women without the disease to detect signs of a process called methylation. The presence of markers for this process suggests that a woman has breast cancer or precancerous breast cells, according to Sukumar.

    Markers of methylation were present in the ductal fluid of 17 of 20 women with breast tumors and in two out of seven women with cancer limited to the breast duct, the researchers report in the April 28th issue of The Lancet. In contrast, Sukumar and her colleagues detected signs of methylation in only 5 out of 45 cancer-free women.

    Ductal lavage is a ``very sensitive, relatively simple test,‘‘ according to Sukumar. The procedure, which takes about half an hour to perform, eventually may become a part of routine breast cancer screening, she said.

    It may allow doctors to ``pick out cancer cells very early in the game‘‘ when cancer cells are too small to be seen on a mammogram. The screen may also benefit women with very dense breast tissue, which makes mammograms difficult to read.

    Ductal lavage ``would be a great tool for assessing risk,‘‘ according to Sukumar. If the screen detected precancerous cells, a woman could be followed more closely to see whether she developed cancer, Sukumar explained. Based on the test, women might be treated with drugs shown to prevent breast cancer.

    Several groups of researchers are working with the new technique, but Sukumar cautioned that the ability of ductal lavage to detect cancer must be confirmed in much larger studies.

    ``It‘s very promising, but it really needs to be tested out in a large number of women,‘‘ she said.