October 5, 2006
Can MRI save lives?
High-tech scans help track down breast cancer in younger at-risk women when mammograms alone fail
In 2003, Leslie Berlin was training six days a week, two hours a day as a figure skater. Two years earlier, while taking lessons with her twin sister, she fell in love with the sport. At 37, she started entering competitions at an age when most professionals hang up their skates. |
"It's something I wanted to do at the amateur level," said Berlin, a San Dimas resident who competes in her own age group. "I feel like when I'm skating I can do anything. It makes anything else seem easy."
But Berlin's life became anything but easy beginning in April of that year. Her mother, Eleanor Tavris, who had survived a battle with stage-three breast cancer nine years earlier, was vigilant about monitoring the health of her three daughters. When a cancer seminar caught her attention, she invited Berlin to come along.
After listening to a presentation from a breast radiologist, Berlin began to worry that her annual mammogram and monthly self-exams might not be adequate enough to detect a tumor.
"I was concerned about my family history and that a percentage of malignancies are missed in mammograms," she said.
She underwent genetic screening and was relieved when her test for a cancer-causing genetic abnormality common among Ashkenazi women came back negative. But Berlin still wasn't convinced she was in the clear. She had been told she had dense breasts, which can obscure the detection of tumors in mammography and ultrasound screenings, and she wanted to be certain she was cancer-free.
Despite her family history of cancer, Berlin's insurance company initially fought her request for magnetic resonance imaging (MRI) of her breasts. MRI scans are expensive, ranging from $1,000 to $6,000.
After she challenged the carrier's decision and won approval for the procedure, Berlin scheduled her test in early April at Cedars-Sinai.
And, indeed, the MRI revealed an aggressive tumor growing inside of Berlin's right breast.
For young, high-risk women like Leslie Berlin, vigilant cancer screening can sometimes mean the difference between a lumpectomy and the loss of one or both breasts to mastectomy. But research is revealing that mammogram screenings by themselves are not a guarantee of catching breast cancer.
No method of detection is 100 percent effective. Mammograms are thought to be about 80 percent effective in women 65 and older, but the reliability drops to 54 percent in women under 40, according to the American Cancer Society's Guidelines for Breast Cancer Screening. Factor in dense breast tissue, which in itself is associated with a higher cancer risk, and the reliability of a mammogram drops further.
Breast cancer remains the second leading cause of death from cancer among American women, with lung cancer topping the list.
This year 213,000 women will be diagnosed with breast cancer in the United States, according to the National Cancer Institute (NCI), and 25 percent of women will be diagnosed with the disease in their lifetime. The NCI puts the breast cancer risk at 60 percent to 80 percent for women of Ashkenazi heritage with a family history of breast or ovarian cancer who also test positive for either the BRCA 1 or BRCA 2 gene mutations.
In addition, researchers believe there's a strong likelihood of as-yet-undiscovered genetic risk factors in the Ashkenazi population that could play a role in breast and ovarian cancer.
Experts recommend that women in such high-risk categories begin mammograms at age 30 or younger and at shorter intervals (e.g., every six months) in order to catch breast cancer in its earliest stages. And MRI is increasingly being recommended as a complimentary screening tool, especially to find invasive tumors, said Dr. Arnold Vinstein of Tower Saint John's Imaging in Santa Monica.
Whereas film and digital mammography uses X-rays to detect changes in the breast and signs abnormalities, MRI finds abnormal tissue by using magnetic fields to measure the reaction of hydrogen atoms in the body.
Recent studies have backed up the reliability of MRI, which has been shown to catch developing tumors that can be missed in traditional mammography. Its accuracy is generally considered to be 90 percent.
With more doctors recommending MRI scans, the S. Mark Taper Foundation Imaging Center at Cedars-Sinai has seen patient numbers jump from a couple every month to five per day over the last five years, said Dr. Rola Saouaf, chief of the center's body and cardiovascular section.
Despite the substantially higher cost of MRI, women like Berlin say the peace of mind is worth the expense.
Without the scan, Berlin believes, "they never would have detected it. I had mammograms every year and it never showed up. My oncologist told me if I didn't have it treated, I'd have had four years to live."
Medical professionals began turning to MRI for breast cancer 10 years ago, and its use has blossomed in the last five years. In July 2004, a landmark study in the New England Journal of Medicine confirmed that MRI is more sensitive than mammography when it comes to detecting tumors in women with an inherited susceptibility to breast cancer.
Cedars-Sinai's Saouaf said she was skeptical of the technology when she started at the hospital five years ago.
"I thought there would be too many false positives," she said, "but I've picked up a lot of tumors."
Saouaf said one of the drawbacks at first was that MRI couldn't always distinguish between cancer and a benign condition, like fibrocystic breast disease. Now a staunch supporter, she said the technology is improving and the scans are increasingly able to determine such differences.
During the procedure, women lie chest down on a movable bed with their breasts inside two coil-lined cylinders, which emit the radiofrequencies. The bed slides into a tube at the center of a 7-by-7-foot cube, and as the machine prepares to scan it emits a noise many patients have described as a rapid hammering or thumping. Labs will often provide patients with personal stereos to help cut down on the noise, as well as sedatives for those who experience anxiety or claustrophobia.
"This is not a pleasure to have," said Vinstein of Tower Saint John's Imaging. "This is a big test."
Patients must lie perfectly still for 15 minutes at a time, with breaks in between, over a period of 30 to 60 minutes. After the first scan, a patient is typically injected with gadolinium, a nonradioactive element that has a strong reaction to the frequencies generated by the machine.
Once a tumor has taken root in the breast, it sets up its own blood supply network. Gadolinium travels through the blood and gathers in abnormal tissue, which contains hydrogen atoms that differ from the same variety in healthy tissue. The MRI looks at the hydrogen in the body, and the gadolinium lights up these diseased areas.
Since the MRI only focuses on how hydrogen atoms react to the magnetic fields, Vinstein said, breast density isn't an issue.
Once the scan is complete, a computer compiles the data into a 3D image. "The computer can detect changes in the pixel color map and make things easier to see," he said.
Diagnostic workstations can now read results in as little as five to 15 minutes. Once the image is complete, it's possible to measure the exact size of the tumor.
In addition to screening for breast cancer, MRI technology has enabled surgeons to map specific tumor locations and perform more accurate biopsies. It has also helped oncologists monitor the effects of chemotherapy based on changes in tumor size.
What the technology is missing at this point is an assessment of whether its use as a screening tool improves survival odds.
"The problem is that there isn't the study to show that by finding the breast cancer early via MRI that the women remain breast cancer-free over a lifetime," he said. "Studies have shown that with mammography women live longer if it's found earlier."
Doctors like Jeffrey Weitzel, director of the Department of Clinical Cancer Genetics and the Cancer Screening and Prevention Program at the City of Hope Comprehensive Cancer Center in Duarte, say there's no point in waiting for mortality studies to prove the effectiveness of MRI.
"We don't need more data to recommend this," he said.
However, Weitzel believes women who don't fall into the high-risk categories do not need MRI and can stick with film or digital mammography. One big reason is cost.
Whereas mammograms might cost $100, an MRI can run $1,000 or more.
Dr. Philomena McAndrew of Tower Hematology Oncology Medical Group in Beverly Hills has been a big supporter of MRI for many years, especially for Ashkenazi women whose grandmothers, mother, aunts or siblings have been diagnosed with cancer. But she reluctantly agrees with Weitzel on cost-effectiveness for low-risk women.
"Unfortunately because of the cost it's clearly for the higher risk groups - inherited mutations such as BRCA 1 and 2 and a prior breast cancer that wasn't picked up a mammogram or ultrasound," said McAndrew, who will be the featured speaker at an Israel Cancer Research Fund event on Oct. 11.
While MRI might carry sticker shock for some, a Stanford study published in the May 24 issue of the Journal of the American Medical Association concluded that use of the technology to screen BRCA 1 carriers under the age of 50 was more cost-effective than simply relying on mammography alone. For BRCA 2 carriers, no such cost-efficiency was found.
Yet in spite of such high accolades, MRI falls short in a key area of breast cancer screening: detecting calcifications.
Calcium deposits in breast tissue are common, and many women will have a least one calcification show up on a mammogram as a bright white fleck. Many are non-cancerous, but calcifications with irregular shapes that form in tight clusters can be an early indication of breast cancer.
But MRI cannot show these calcifications.
Vinstein of Tower Saint John's Imaging said that while revolutionary, MRIs are intended to compliment rather than replace the mammogram. He believes the widely used X-ray technique still plays a critical role in cancer screening.
"Unless a patient has had a mammogram in the last six month, we'll have her repeat one and get an ultrasound," he said.
Leslie Berlin credits the MRI with helping to save her life.
A biopsy found her cancer was fueled by estrogen, and was too aggressive to consider lumpectomy. After consulting with her oncologist, she decided to have a double mastectomy to avoid future problems.
"I didn't want to go through this again, and it probably would have happened again," she said.
On April 23, 2003, Berlin underwent surgery at Cedars-Sinai, the same hospital where she and her twin sister had been born more than two months premature. "They saved my life twice," she said.
After she completed her chemotherapy and radiation treatments, Berlin also had her ovaries removed to reduce the estrogen levels in her body that had fed the tumor.
"My oncologist said if I'd gotten pregnant it would have been a death sentence," she said.
After a two-year cancer fight, Berlin said she's fearless about explaining the shortcomings of cancer screening techniques to a group of strangers.
"When I hear people talking about mammograms, I stick my nose in and tell them about my experience," she said.
Berlin says what she missed most during her battle was spending time on the ice. Her brown hair has grown back since the chemotherapy, and over the last year her strength has returned gradually. At 40 years old she's training with two coaches and looking forward to entering competitions.
"I feel like my old self again," she said.