Pink Pack: Molecular Breast Imaging

Reported by Frances Weller - bio|email
Posted by Debra Worley - email

(WECT) - While mammograms save lives, it's not enough for the millions of women who have dense breast tissues.

Doctors have designed a new type of technology that picks up the tumors that mammograms miss.

A few years ago, a mammogram found Marcia Maring had breast cancer, but like 25% of women, she has dense breast which makes it hard to detect tumors.

"In fact, in those women mammography can miss one out of every two cancers," said Dr. Deborah Rhodes with the Mayo Clinic.

A team of doctors at the Mayo Clinic developed Molecular Breast Imaging, MBI.  Women get an injection of a radioactive tracer that travels to the tumor cells and lights them up.

"It's like seeing a lighthouse," said Dr. Michael O'Connor.  "You see this beacon in the breast and it's very easy to pick up the tumor."

In a study of more than 900 women, MBI picked up three times as many cancerous tumors as a mammogram.

"We've shown we can detect even very small cancers - those that are under 10 millimeters," said Dr. Carrie Hruska.

"In about 10 percent of the cases we would also find additional small tumors that the mammogram was missing," said Dr. Rhodes.

In the study, the MBI found a second tumor Maring's mammogram missed.  Finding the tumor changed the course of her treatment.

After surgery and chemo, Maring's a healthy mom getting ready to send her kids to college.

For more information, please contact:
Dana Sparks
Media Relations
Mayo Clinic
(507) 538-0844

BACKGROUND: A screening mammogram is an X-ray of the breast used to detect breast changes in women who have no signs or symptoms of breast cancer. It usually involves two X-rays of each breast. Mammograms make it possible to detect tumors that cannot be felt. Mammograms can also find tiny deposits of calcium in the breast that sometimes indicate the presence of breast cancer. Women age 40 and older should have mammograms every one to two years. Women who are at a higher than average risk of breast cancer should talk with their health care providers about whether to have mammograms before age 40 and how often to have them.

LIMITATIONS: Even though mammography can detect tumors that cannot be felt, finding a small tumor does not always mean that a woman's life will be saved. Mammography may not help a woman with a fast-growing or aggressive cancer that has already spread to other parts of her body before being detected. In addition, mammograms aren't always completely accurate. False negatives occur when mammograms appear normal even though breast cancer is present. Overall, mammograms miss up to 20 percent of the breast cancers that are present at the time of screening. False negatives occur more often in younger women than in older women because the dense breasts of younger women make breast cancers more difficult to detect in mammograms. As women age, their breasts usually become more fatty and breast cancers become easier to detect with screening mammograms. False positives occur when mammograms are read by a radiologist as abnormal, but no cancer is actually present.  All abnormal mammograms should be followed up with additional testing to determine if cancer is present.

DENSE BREASTS: Cancer turns up five-times more often in women with extremely dense breast than in those with the most fatty tissue, a recent study shows. On mammograms, fat looks dark, but dense tissue is light, like tumors so it can hide the cancers. This means that density is a true risk factor, along with other strong predictors like age and genetics. In a study published in the New England Journal of Medicine, women with at least 75 percent dense breasts showed five times more likelihood of cancer than women with less than ten percent density.  Cancers were 18 times more likely in women with the densest breasts within the first year after mammograms.

MOLECULAR BREAST IMAGING: In the largest-ever study to compare molecular breast imaging to mammography, researchers showed that MBI can detect three-times as many cancers in women who have dense breast patterns on their mammograms and are at increased risk of breast cancer. MBI is a relatively new screening method. Patients are injected with a short-living radioactive agent that is absorbed by breast tissue. This agent is tracked with a pecialized camera that can distinguish healthy tissue from breast cancer tumors, as cancer cells
absorb more of the radioactive agent than healthy cells. MBI is currently available at a limited number of cancer centers, but its availability is growing. Nine hundred and forty women were included in this study and were screened with both MBI and mammography. Participants had to meet two criteria.

First, their breasts were determined to be dense by a previous mammogram. Second, they had an increased risk of breast cancer. A total of 13 tumors in 12 patients were detected; eight by MBI alone, one by mammography alone.

Copyright © 2009 Ivanhoe Broadcast News, Inc