Mammography is currently the best tool doctors have for finding cancer before it spreads beyond the breast. Properly performed and interpreted, this special type of X-ray can detect cancer cells up to two years before a woman or her doctor can feel a lump. "It is the gold standard for detecting early breast cancer," said Marie Zinninger, assistant executive director of the American College of Radiology (ACR).
If a malignancy is present in a woman over 50, mammography has a 90% percent chance of finding it. A screening test with a sensitivity of 90% is quite valuable, as it yields false results for only 10% of women with breast cancer. Unfortunately, mammography's specificity, its ability to distinguish between a benign abnormality and a malignancy, is poor: (10%) 9 out of 10 times the suspicious area turns out to be noncancerous. In order to arrive at this good news, a woman whose X-ray indicates a problem must undergo additional testing that can be stressful, time consuming, and costly.
In addition to mammography's inherent limitations as a screening tool, its accuracy is affected by the skill of the technologist who takes the image, the proficiency of the radiologist who interprets it, and how well the X- ray equipment has been calibrated.
Zinninger oversees the ACR's voluntary accreditation program, which ensures that mammography facilities meet the organization's safety and accuracy standards. Staff training is also closely scrutinized during accreditation. One-third of the facilities that seek ACR approval do not initially pass muster; in some cases technologists were not adequately trained to position and compress the breast. These skills are crucial because proper compression provides clear, easy-to-interpret views of the breast using the smallest possible dose of radiation. In other centers it's the machines, not the people, that are problematic. Nearly one out of six facilities are initially rejected by the ACR because their equipment is not accurately calibrated.
Finding a center that does high-quality mammography can be a crapshoot. Not all sign up for voluntary accreditation and even fewer meet ACR standards. The odds of finding a top-notch facility are especially bad for women in rural areas where the choice of centers is limited.
Finally, price is no proof of quality. A center that charges $125 for the procedure is no more reliable than one charging $50.
In 12 states, fewer than half of facilities are accredited, either because they haven't applied or they flunked ACR's requirements. Alaska has the fewest number -- only 8 out of 36. At the other end of the spectrum is Vermont where all of the state's 20 units are accredited.
Two years ago Congress passed a bill aimed at making sure that every woman has access to high quality mammograms. This law requires all facilities to be accredited and certified by the Department of Health and Human Services by October 1, 1994. ACR will continue providing certification while a coalition of agencies develops professional educational programs and quality assurance protocols.
They have their work cut out for them: there are currently no uniform standards for training the technologists who perform mammograms or the radiologists who interpret the films. Only half the states license radiological technicians. "In many states, anyone can perform mammography -- even a medical secretary," said Zinninger. "Most women's hairdressers are better regulated than radiological technologists."
When a doctor refers a woman to a mammography facility, she can find out if it is accredited by checking with the National Cancer Institute (1- 800-4-CANCER) or the American Cancer Society (1-800-ACS-2345). She can also look for an accreditation certificate on the wall or a sticker on the mammography unit.
Women should not have a mammogram in an unaccredited facility until they have gotten answers to the following questions.
A woman must undress from the waist up before the test. If she is wearing antiperspirant or talc, she will be asked to wash it off because aluminum and other minerals in these products can show up on the X-ray and may be mistaken for microcalcifications, tiny deposits of calcium in breast tissue. She then stands in front of the machine which has a camera positioned above the breasts. A technologist (usually female) positions one of her breasts on the lower of the two compression plates and then slowly brings the top plate down to flatten the breast. The most unpleasant part of the procedure is that the plates are usually cold. Although the pressure applied to the breast is uncomfortable, it typically isn't painful.
The technologist will take a side and front view of the breast, then repeat the procedure on the other side. Women with breast implants may require additional views. At some facilities, the radiologist will give the film a quick scan and ask for another picture if the image is unclear. The whole procedure takes about 15 minutes
The radiologist will usually wait until the end of the day to check the films for opaque white areas, the telltale sign of an abnormality. The woman or her doctor should be notified of the results within a day or two. Facilities used to tell women that "no news is good news," but that approach is unacceptable today, said Zinninger.
Until researchers develop blood tests that can detect molecular markers for breast cancer, mammography is the best way to spot the disease early enough to treat successfully.
One in 10 women who have a screening mammogram will go through the gut-wrenching experience of being notified that the X-ray picked up an abnormality. Fortunately, 90% of these "suspicious" areas turn out to be cysts, benign microcalcifications, or noncancerous growths. The ACR developed five classifications to describe mammography results:
If Category 2-4 abnormalities are found, you should get a second opinion from another radiologist, a breast surgeon, or a surgical oncologist, advises Janet Osuch associate professor of surgery at Michigan State University School of Medicine.
Your doctor will likely recommend a repeat mammogram to verify the first one. In the second procedure, the technologist may compress the suspicious-looking area to determine whether the abnormality is real or an artifact (such as necks of aluminum from deodorant), or he or she may take a magnified view of an area with microcalcifications .
If both films agree, follow-up tests are needed to determine whether the lesion is malignant. Depending on its size and characteristics, the doctor will opt for one of the following diagnostic procedures:
Ultrasound. This test is used "when a lump shows up on a mammogram but is too small for the doctor to feel," says Dr. Osuch. Ultrasound, which uses sound waves to create a picture, can reveal whether the lump is solid or is a fluid-filled cyst.
Needle Aspiration. "When the lump is large enough to be felt, needle aspiration will immediately tell the doctor if it is cystic or solid," says Dr. Osuch. In this procedure, fluid and tissue are withdrawn from the mass through a fine needle. If the fluid is clear, the doctor can drain the cyst on the spot by pulling out the rest of the fluid. Otherwise, the sample is sent to a pathologist for study.
Biopsy. This is used to remove tissue from a suspicious area so that it can be examined by a pathologist. With aspiration biopsy, a sample of cells is withdrawn through a needle; this can be done in a doctor's office. Surgical biopsy, in which part or all of the mass is re- moved through an incision, requires anesthesia and is performed in a surgical clinic or hospital on an outpatient basis. With an incisional biopsy, only part of the tumor is removed; excisional biopsy involves removing the entire mass plus a perimeter of normal- looking tissue. (If the tumor is malignant, the procedure becomes a lumpectomy). As with any other surgical procedure, biopsies carry a risk of bleeding, infection, and scarring.