2009年3月31日 星期二


Alternating mammography and MRI may be best for high-risk women
交替使用乳房X光攝影與乳房磁振造影 是乳癌高危險群婦女的最佳選擇

MRI alternated with mammography at six-month intervals can detect breast cancers not identified by mammography alone, a research team from the Houston-based University of Texas M. D. Anderson Cancer Center reported at the San Antonio Breast Cancer Symposium.

MRI is known to be more sensitive in detecting breast cancers than mammography, with a 71-percent to 100-percent accuracy compared to a 16-percent to 40-percent accuracy for mammography. As a result, annual breast cancer screening for high-risk women now typically includes MRI along with mammography and a clinical breast exam.

“In the high-risk population, the recent standard of practice is to perform mammography and MRI every year,” says Huong Le-Petross, MD, assistant professor of diagnostic radiology at M. D. Anderson and the study’s first author. “What we started to do at M. D. Anderson was to see if we could do mammography and then six months later do a breast MRI exam, followed six months later with a mammogram exam, and then six months after that with a breast MRI. That way the women would receive an imaging modality screening every six months.”
『對乳癌高危險群這一類婦女而言,近期乳癌篩檢標準逐漸出現乳房X光攝影與乳房磁振造影並行的趨勢。』該項研究的第一作者,醫學博士Le-Petross 說:『我們在M.D.安德森的研究進行方式是以6個月作為間隔,交替使用乳房X光攝影與乳房磁振造影作為篩檢工具,通過這個方式,參加研究的婦女每隔6個月就會收到一份模式化的篩檢影像。』

In the pilot study, which was presented at a poster session in December, the researchers performed a retrospective chart review of 334 women who had participated in a high-risk breast cancer-screening program at M. D. Anderson from January 1997 to December 2007. The women had undergone between one and four MRI screening cycles and were considered to be at high risk if they had hereditary breast and ovarian cancer syndrome, a personal history of breast cancer, a biopsy indicating atypia or lobular carcinoma in situ (LCIS), or a 20 percent or higher lifetime risk of developing breast cancer, as estimated by the Gail model.
這場公佈於12月份璧報論文的實驗性研究中,研究者提出一份圖表,回溯M.D.安德森於1997年1月至2007年12月乳癌篩檢計畫的成果。334位參與此項計畫的婦女,皆為擁有家族及個人乳癌病史及卵巢癌綜合症、或是曾因非典型癌前病變及乳小葉原位癌做過穿刺切片、或是被 Gail model確認終生具有20%罹患乳癌機率者。而這些被認為是乳癌高危險群的婦女,皆個別經歷過一至四個磁振造影的篩檢週期。

In the all-M. D. Anderson study, 86 of the 334 high-risk women (26 percent) underwent this alternating approach. Among this group, 46 percent completed the first round of MRI screening, 28 percent completed the second round, 13 percent completed the third round, and 4 percent completed the fourth round. The other 248 women underwent prophylactic mastectomy or were started on chemoprevention agents. All study participants were given a clinical breast exam every six months. The median follow-up time was two years, with a range of one to four years.

The alternating MRI and mammography screening program detected nine cancers among the 86 women – five invasive ductal carcinomas, three invasive lobular carcinoma, and two ductal carcinomas in situ. Five (55 percent) of these cancers were identified by MRI but not by mammography, three (33 percent) were found by both MRI and mammography, and one (11 percent) cancer, a tumor 1 millimeter in size, was overlooked by both screening techniques. No cancer was detected by mammography alone.

“We found that MRI picked up the majority of cancers, while mammography picked up only three out of the nine,” Le-Petross notes. With five of the eight cancers detected by MRI, the mammogram from six months earlier was either normal or suggested benign findings.
『我們發現乳房磁振造影是這項研究中偵測乳癌的主要篩檢工具,乳房X光攝影只發現了9起癌症中的3起。』 Le-Petross解釋道:『當乳房磁振造影發現8起乳癌中的5起時,乳房X光攝影在這些癌症確診前的6個月,只給了正常或是發現良性病灶的註解。』

“The global picture is that MRI can pick up cancers that mammography cannot,” Le-Petross says. “This would suggest that, in this population, it is more beneficial for the patient to have screening MRI so that we can pick up small lesions before a mammogram can detect them.”

One important unanswered question is whether an alternating MRI and mammography screening program will save lives. “That is going to take a five- to 10-year follow-up to determine,” Le-Petross adds. “It is an exciting question because mammography has always been the standard, and now we are challenging that gold standard examination.”

In addition to Le-Petross, other authors on the all-M. D. Anderson study include: Gabriel Hortobagyi, MD, professor and chair of the Department of Breast Medical Oncology; Banu Arun, MD, associate professor in the Departments of Breast Medical Oncology and Cancer Prevention, and the study’s senior author; Deanna Atchley, Department of Breast Medical Oncology; and Gary Whitman, MD, professor in the Department of Radiology.

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