Alternating mammography, MRI may be best for high-risk women
Rotating MRI with mammography at six-month intervals can detect breast cancers not identified by mammography alone, according to research from the University of Texas M. D. Anderson Cancer Center presented at the 31st annual CRTC-AACR San Antonio Breast Cancer Symposium last week.
Annual breast cancer screening for high-risk women now typically includes MRI along with mammography and a clinical breast exam, according to the researchers.
In the pilot study, 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, or a 20 percent or higher lifetime risk of developing breast cancer, as estimated by the Gail model.
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 authors said.
According to the results, 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. Fifty-five percent of the cancers were identified by MRI but not by mammography; 33 percent were found by both MRI and mammography; and 11 percent cancer, a tumor one 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," said the study's first author Huong Le-Petross, MD, assistant professor of diagnostic radiology at M. D. Anderson. “With five of the eight cancers detected by MRI, the mammogram from six months earlier was either normal or suggested benign findings.
Le-Petross said that the findings suggest that in this population it is more beneficial for the patient to have screening MRI so that small lesions can be identified before a mammogram can detect them.
Annual breast cancer screening for high-risk women now typically includes MRI along with mammography and a clinical breast exam, according to the researchers.
In the pilot study, 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, or a 20 percent or higher lifetime risk of developing breast cancer, as estimated by the Gail model.
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 authors said.
According to the results, 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. Fifty-five percent of the cancers were identified by MRI but not by mammography; 33 percent were found by both MRI and mammography; and 11 percent cancer, a tumor one 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," said the study's first author Huong Le-Petross, MD, assistant professor of diagnostic radiology at M. D. Anderson. “With five of the eight cancers detected by MRI, the mammogram from six months earlier was either normal or suggested benign findings.
Le-Petross said that the findings suggest that in this population it is more beneficial for the patient to have screening MRI so that small lesions can be identified before a mammogram can detect them.