The uncomfortable truth is that mammograms miss 10 percent to 30 percent of breast cancers and have a worse record in women whose breast tissue is dense. The good news is that doctors are exploring new ways to spot those cancers in their earliest stages, when they may look like nothing much at all.
"Screening mammography has been the workhorse for early detection since the 1960s," says Dr. Brett Parkinson, director of breast imaging services for Intermountain Health Care, and that screening has played a big part in decreasing the mortality rate of breast cancer patients by 30 percent to 40 percent. But because mammography isn't perfect, doctors are looking at technologies such as ultrasound and magnetic resonance imaging (MRI) as supplements to mammography, he says.
Parkinson and Dr. Vilija Avizonis, a radiation oncologist at LDS Hospital, will participate in the Deseret News/Intermountain Health Care Hotline on Saturday. From 10 a.m. to noon, the doctors will answer calls about detection and treatment of breast cancer, as part of Breast Cancer Awareness Month.
A multi-institutional study is currently under way comparing ultrasound and mammography. The study, which began last May, will provide women with both modalities and then determine which has a better track record in spotting cancers.
Despite its problems, Parkinson says, mammography is good at picking up the earliest and most treatable form of breast cancer, known as ductal carcinoma in situ — a cancer that ultrasound often misses. On the other hand, ultrasound can spot cancers that mammography misses and is particularly adept at seeing through dense breast tissue. Similarly, MRIs were found, in a Dutch study, to pick up more breast cancers in women with dense breast tissue.
But because these techniques are more expensive than traditional mammography, most insurance companies and Medicare won't pay for ultrasound or MRIs for initial breast screening in asymptomatic women.
Parkinson predicts that within a few years ultrasound and MRI screening will be more common for women who have both dense tissue and risk factors for breast cancer.
In the meantime, both ultrasound and MRIs are commonly used for follow-up screening in women whose mammograms look suspicious. MRIs are also used for women with known breast cancer, to define the extent of the disease.
Some hospitals use MRIs to guide surgeons during biopsy. And PET scans are occasionally used, in conjunction with CT scans and MRIs, to measure the extent of an advancing disease in women whose breast cancer has metastasized.
A study is also under way to determine whether digital mammography is any better than old-fashioned analog mammography in spotting masses and calcifications that might be cancerous. The study, which will look at 49,000 women at 34 centers in the United States and Canada, will be published next year. Smaller, previous studies have found digital and analog equal as sleuths. If the current study finds digital to be the clear winner, "you'll see a rush of places converting to digital," Parkinson predicts, as more manufacturers provide the technology and the price comes down.
Digital mammography has the advantage of being easier to store and to transfer images to other hospitals, but currently the equipment is four times as expensive as traditional mammography.
Last week, LDS Hospital announced that it will also study the relative merits of traditional mammogram film versus digital mammography beefed up by a process known as "computer-aided detection."
Doctors recommend yearly mammograms for women 40 and over. Any woman with a palpable lump should have both mammography and ultrasound screening, Parkinson says. And women with a history of premenstrual breast cancers in their families should schedule their first mammogram to coincide with the age when that relative was first diagnosed minus 10 years.
Saturday: Breast cancer treatment
Call the hotline Saturday
Saturday's Deseret Morning News/Intermountain Health Care Hotline focuses on breast cancer. Dr. Brett Parkinson, chief of mammography at LDS Hospital and director of breast imaging services for Intermountain Health Care, and Dr. Vilija Avizonis, radiation oncologist at LDS Hospital, will answer questions about detection and treatment. They will take calls from 10 a.m. to noon. The toll-free number from anywhere in the Intermountain region is 1-800-925-8177. All calls are confidential.